gpiolib.c 64.6 KB
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#include <linux/kernel.h>
#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/device.h>
#include <linux/err.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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#include <linux/acpi_gpio.h>
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#include <linux/idr.h>
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#include <linux/slab.h>
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#include <linux/acpi.h>
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#include <linux/gpio/driver.h>
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#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
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/* Implementation infrastructure for GPIO interfaces.
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 *
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 * The GPIO programming interface allows for inlining speed-critical
 * get/set operations for common cases, so that access to SOC-integrated
 * GPIOs can sometimes cost only an instruction or two per bit.
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 */


/* When debugging, extend minimal trust to callers and platform code.
 * Also emit diagnostic messages that may help initial bringup, when
 * board setup or driver bugs are most common.
 *
 * Otherwise, minimize overhead in what may be bitbanging codepaths.
 */
#ifdef	DEBUG
#define	extra_checks	1
#else
#define	extra_checks	0
#endif

/* gpio_lock prevents conflicts during gpio_desc[] table updates.
 * While any GPIO is requested, its gpio_chip is not removable;
 * each GPIO's "requested" flag serves as a lock and refcount.
 */
static DEFINE_SPINLOCK(gpio_lock);

struct gpio_desc {
	struct gpio_chip	*chip;
	unsigned long		flags;
/* flag symbols are bit numbers */
#define FLAG_REQUESTED	0
#define FLAG_IS_OUT	1
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#define FLAG_EXPORT	2	/* protected by sysfs_lock */
#define FLAG_SYSFS	3	/* exported via /sys/class/gpio/control */
#define FLAG_TRIG_FALL	4	/* trigger on falling edge */
#define FLAG_TRIG_RISE	5	/* trigger on rising edge */
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#define FLAG_ACTIVE_LOW	6	/* value has active low */
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#define FLAG_OPEN_DRAIN	7	/* Gpio is open drain type */
#define FLAG_OPEN_SOURCE 8	/* Gpio is open source type */
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#define FLAG_USED_AS_IRQ 9	/* GPIO is connected to an IRQ */
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#define ID_SHIFT	16	/* add new flags before this one */
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#define GPIO_FLAGS_MASK		((1 << ID_SHIFT) - 1)
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#define GPIO_TRIGGER_MASK	(BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
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#ifdef CONFIG_DEBUG_FS
	const char		*label;
#endif
};
static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];

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#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)

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static DEFINE_MUTEX(gpio_lookup_lock);
static LIST_HEAD(gpio_lookup_list);
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static LIST_HEAD(gpio_chips);

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#ifdef CONFIG_GPIO_SYSFS
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static DEFINE_IDR(dirent_idr);
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#endif

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static int gpiod_request(struct gpio_desc *desc, const char *label);
static void gpiod_free(struct gpio_desc *desc);

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#ifdef CONFIG_DEBUG_FS
#define gpiod_emerg(desc, fmt, ...)			                \
	pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label, \
                 ##__VA_ARGS__)
#define gpiod_crit(desc, fmt, ...)			                \
	pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                 ##__VA_ARGS__)
#define gpiod_err(desc, fmt, ...)				        \
	pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,   \
                 ##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...)				        \
	pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                 ##__VA_ARGS__)
#define gpiod_info(desc, fmt, ...)				        \
	pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                ##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...)				   \
	pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label, \
                 ##__VA_ARGS__)
#else
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#define gpiod_emerg(desc, fmt, ...)			           \
	pr_emerg("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_crit(desc, fmt, ...)			           \
	pr_crit("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_err(desc, fmt, ...)				   \
	pr_err("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...)				   \
	pr_warn("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_info(desc, fmt, ...)				   \
	pr_info("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...)				   \
	pr_debug("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
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#endif
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static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
#ifdef CONFIG_DEBUG_FS
	d->label = label;
#endif
}

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/*
 * Return the GPIO number of the passed descriptor relative to its chip
 */
static int gpio_chip_hwgpio(const struct gpio_desc *desc)
{
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	return desc - &desc->chip->desc[0];
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}

/**
 * Convert a GPIO number to its descriptor
 */
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struct gpio_desc *gpio_to_desc(unsigned gpio)
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{
	if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
		return NULL;
	else
		return &gpio_desc[gpio];
}
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EXPORT_SYMBOL_GPL(gpio_to_desc);
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/**
 * Convert an offset on a certain chip to a corresponding descriptor
 */
static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip,
						 unsigned int offset)
{
	unsigned int gpio = chip->base + offset;

	return gpio_to_desc(gpio);
}
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/**
 * Convert a GPIO descriptor to the integer namespace.
 * This should disappear in the future but is needed since we still
 * use GPIO numbers for error messages and sysfs nodes
 */
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int desc_to_gpio(const struct gpio_desc *desc)
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{
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	return desc - &gpio_desc[0];
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}
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EXPORT_SYMBOL_GPL(desc_to_gpio);
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/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
 * when setting direction, and otherwise illegal.  Until board setup code
 * and drivers use explicit requests everywhere (which won't happen when
 * those calls have no teeth) we can't avoid autorequesting.  This nag
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 * message should motivate switching to explicit requests... so should
 * the weaker cleanup after faults, compared to gpio_request().
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 *
 * NOTE: the autorequest mechanism is going away; at this point it's
 * only "legal" in the sense that (old) code using it won't break yet,
 * but instead only triggers a WARN() stack dump.
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 */
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static int gpio_ensure_requested(struct gpio_desc *desc)
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{
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	const struct gpio_chip *chip = desc->chip;
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	const int gpio = desc_to_gpio(desc);
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	if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
			"autorequest GPIO-%d\n", gpio)) {
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		if (!try_module_get(chip->owner)) {
			pr_err("GPIO-%d: module can't be gotten \n", gpio);
			clear_bit(FLAG_REQUESTED, &desc->flags);
			/* lose */
			return -EIO;
		}
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		desc_set_label(desc, "[auto]");
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		/* caller must chip->request() w/o spinlock */
		if (chip->request)
			return 1;
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	}
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	return 0;
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}

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/**
 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
 * @desc:	descriptor to return the chip of
 */
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
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{
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	return desc ? desc->chip : NULL;
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}
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EXPORT_SYMBOL_GPL(gpiod_to_chip);
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/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
{
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	struct gpio_chip *chip;
	int base = ARCH_NR_GPIOS - ngpio;
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	list_for_each_entry_reverse(chip, &gpio_chips, list) {
		/* found a free space? */
		if (chip->base + chip->ngpio <= base)
			break;
		else
			/* nope, check the space right before the chip */
			base = chip->base - ngpio;
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	}

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	if (gpio_is_valid(base)) {
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		pr_debug("%s: found new base at %d\n", __func__, base);
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		return base;
	} else {
		pr_err("%s: cannot find free range\n", __func__);
		return -ENOSPC;
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	}
}

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/**
 * gpiod_get_direction - return the current direction of a GPIO
 * @desc:	GPIO to get the direction of
 *
 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
 *
 * This function may sleep if gpiod_cansleep() is true.
 */
int gpiod_get_direction(const struct gpio_desc *desc)
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{
	struct gpio_chip	*chip;
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	unsigned		offset;
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	int			status = -EINVAL;

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	chip = gpiod_to_chip(desc);
	offset = gpio_chip_hwgpio(desc);
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	if (!chip->get_direction)
		return status;

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	status = chip->get_direction(chip, offset);
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	if (status > 0) {
		/* GPIOF_DIR_IN, or other positive */
		status = 1;
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		/* FLAG_IS_OUT is just a cache of the result of get_direction(),
		 * so it does not affect constness per se */
		clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
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	}
	if (status == 0) {
		/* GPIOF_DIR_OUT */
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		set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
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	}
	return status;
}
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EXPORT_SYMBOL_GPL(gpiod_get_direction);
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#ifdef CONFIG_GPIO_SYSFS

/* lock protects against unexport_gpio() being called while
 * sysfs files are active.
 */
static DEFINE_MUTEX(sysfs_lock);

/*
 * /sys/class/gpio/gpioN... only for GPIOs that are exported
 *   /direction
 *      * MAY BE OMITTED if kernel won't allow direction changes
 *      * is read/write as "in" or "out"
 *      * may also be written as "high" or "low", initializing
 *        output value as specified ("out" implies "low")
 *   /value
 *      * always readable, subject to hardware behavior
 *      * may be writable, as zero/nonzero
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 *   /edge
 *      * configures behavior of poll(2) on /value
 *      * available only if pin can generate IRQs on input
 *      * is read/write as "none", "falling", "rising", or "both"
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 *   /active_low
 *      * configures polarity of /value
 *      * is read/write as zero/nonzero
 *      * also affects existing and subsequent "falling" and "rising"
 *        /edge configuration
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 */

static ssize_t gpio_direction_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
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	const struct gpio_desc	*desc = dev_get_drvdata(dev);
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	ssize_t			status;

	mutex_lock(&sysfs_lock);

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	if (!test_bit(FLAG_EXPORT, &desc->flags)) {
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		status = -EIO;
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	} else {
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		gpiod_get_direction(desc);
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		status = sprintf(buf, "%s\n",
			test_bit(FLAG_IS_OUT, &desc->flags)
				? "out" : "in");
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	}
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	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_direction_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
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	struct gpio_desc	*desc = dev_get_drvdata(dev);
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	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else if (sysfs_streq(buf, "high"))
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		status = gpiod_direction_output(desc, 1);
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	else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
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		status = gpiod_direction_output(desc, 0);
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	else if (sysfs_streq(buf, "in"))
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		status = gpiod_direction_input(desc);
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	else
		status = -EINVAL;

	mutex_unlock(&sysfs_lock);
	return status ? : size;
}

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static /* const */ DEVICE_ATTR(direction, 0644,
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		gpio_direction_show, gpio_direction_store);

static ssize_t gpio_value_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
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	struct gpio_desc	*desc = dev_get_drvdata(dev);
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	ssize_t			status;

	mutex_lock(&sysfs_lock);

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	if (!test_bit(FLAG_EXPORT, &desc->flags))
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		status = -EIO;
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	else
		status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));
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	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_value_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
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	struct gpio_desc	*desc = dev_get_drvdata(dev);
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	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else if (!test_bit(FLAG_IS_OUT, &desc->flags))
		status = -EPERM;
	else {
		long		value;

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		status = kstrtol(buf, 0, &value);
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		if (status == 0) {
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			gpiod_set_value_cansleep(desc, value);
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			status = size;
		}
	}

	mutex_unlock(&sysfs_lock);
	return status;
}

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static const DEVICE_ATTR(value, 0644,
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		gpio_value_show, gpio_value_store);

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static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
{
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	struct sysfs_dirent	*value_sd = priv;
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	sysfs_notify_dirent(value_sd);
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	return IRQ_HANDLED;
}

static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
		unsigned long gpio_flags)
{
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	struct sysfs_dirent	*value_sd;
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	unsigned long		irq_flags;
	int			ret, irq, id;

	if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
		return 0;

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	irq = gpiod_to_irq(desc);
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	if (irq < 0)
		return -EIO;

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	id = desc->flags >> ID_SHIFT;
	value_sd = idr_find(&dirent_idr, id);
	if (value_sd)
		free_irq(irq, value_sd);
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	desc->flags &= ~GPIO_TRIGGER_MASK;

	if (!gpio_flags) {
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		gpiod_unlock_as_irq(desc);
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		ret = 0;
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		goto free_id;
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	}

	irq_flags = IRQF_SHARED;
	if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
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		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
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	if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
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		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
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	if (!value_sd) {
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		value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
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		if (!value_sd) {
			ret = -ENODEV;
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			goto err_out;
		}

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		ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
		if (ret < 0)
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			goto free_sd;
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		id = ret;
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		desc->flags &= GPIO_FLAGS_MASK;
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		desc->flags |= (unsigned long)id << ID_SHIFT;
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		if (desc->flags >> ID_SHIFT != id) {
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			ret = -ERANGE;
			goto free_id;
		}
	}

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	ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
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				"gpiolib", value_sd);
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	if (ret < 0)
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		goto free_id;
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	ret = gpiod_lock_as_irq(desc);
	if (ret < 0) {
		gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
		goto free_id;
	}

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	desc->flags |= gpio_flags;
	return 0;

free_id:
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	idr_remove(&dirent_idr, id);
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	desc->flags &= GPIO_FLAGS_MASK;
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free_sd:
	if (value_sd)
		sysfs_put(value_sd);
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err_out:
	return ret;
}

static const struct {
	const char *name;
	unsigned long flags;
} trigger_types[] = {
	{ "none",    0 },
	{ "falling", BIT(FLAG_TRIG_FALL) },
	{ "rising",  BIT(FLAG_TRIG_RISE) },
	{ "both",    BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
};

static ssize_t gpio_edge_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	const struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else {
		int i;

		status = 0;
		for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
			if ((desc->flags & GPIO_TRIGGER_MASK)
					== trigger_types[i].flags) {
				status = sprintf(buf, "%s\n",
						 trigger_types[i].name);
				break;
			}
	}

	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_edge_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;
	int			i;

	for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
		if (sysfs_streq(trigger_types[i].name, buf))
			goto found;
	return -EINVAL;

found:
	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else {
		status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
		if (!status)
			status = size;
	}

	mutex_unlock(&sysfs_lock);

	return status;
}

static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);

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static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
				int value)
{
	int			status = 0;

	if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
		return 0;

	if (value)
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
	else
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);

	/* reconfigure poll(2) support if enabled on one edge only */
	if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
				!!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
		unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;

		gpio_setup_irq(desc, dev, 0);
		status = gpio_setup_irq(desc, dev, trigger_flags);
	}

	return status;
}

static ssize_t gpio_active_low_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	const struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else
		status = sprintf(buf, "%d\n",
				!!test_bit(FLAG_ACTIVE_LOW, &desc->flags));

	mutex_unlock(&sysfs_lock);

	return status;
}

static ssize_t gpio_active_low_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags)) {
		status = -EIO;
	} else {
		long		value;

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		status = kstrtol(buf, 0, &value);
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		if (status == 0)
			status = sysfs_set_active_low(desc, dev, value != 0);
	}

	mutex_unlock(&sysfs_lock);

	return status ? : size;
}

static const DEVICE_ATTR(active_low, 0644,
		gpio_active_low_show, gpio_active_low_store);

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static const struct attribute *gpio_attrs[] = {
	&dev_attr_value.attr,
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	&dev_attr_active_low.attr,
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	NULL,
};

static const struct attribute_group gpio_attr_group = {
	.attrs = (struct attribute **) gpio_attrs,
};

/*
 * /sys/class/gpio/gpiochipN/
 *   /base ... matching gpio_chip.base (N)
 *   /label ... matching gpio_chip.label
 *   /ngpio ... matching gpio_chip.ngpio
 */

static ssize_t chip_base_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", chip->base);
}
static DEVICE_ATTR(base, 0444, chip_base_show, NULL);

static ssize_t chip_label_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", chip->label ? : "");
}
static DEVICE_ATTR(label, 0444, chip_label_show, NULL);

static ssize_t chip_ngpio_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", chip->ngpio);
}
static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);

static const struct attribute *gpiochip_attrs[] = {
	&dev_attr_base.attr,
	&dev_attr_label.attr,
	&dev_attr_ngpio.attr,
	NULL,
};

static const struct attribute_group gpiochip_attr_group = {
	.attrs = (struct attribute **) gpiochip_attrs,
};

/*
 * /sys/class/gpio/export ... write-only
 *	integer N ... number of GPIO to export (full access)
 * /sys/class/gpio/unexport ... write-only
 *	integer N ... number of GPIO to unexport
 */
680 681 682
static ssize_t export_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
D
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683
{
684 685 686
	long			gpio;
	struct gpio_desc	*desc;
	int			status;
D
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687

688
	status = kstrtol(buf, 0, &gpio);
D
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689 690 691
	if (status < 0)
		goto done;

692
	desc = gpio_to_desc(gpio);
693 694 695 696 697
	/* reject invalid GPIOs */
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}
698

D
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699 700 701 702 703
	/* No extra locking here; FLAG_SYSFS just signifies that the
	 * request and export were done by on behalf of userspace, so
	 * they may be undone on its behalf too.
	 */

704
	status = gpiod_request(desc, "sysfs");
705 706 707
	if (status < 0) {
		if (status == -EPROBE_DEFER)
			status = -ENODEV;
D
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708
		goto done;
709
	}
710
	status = gpiod_export(desc, true);
D
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711
	if (status < 0)
712
		gpiod_free(desc);
D
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713
	else
714
		set_bit(FLAG_SYSFS, &desc->flags);
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715 716 717 718 719 720 721

done:
	if (status)
		pr_debug("%s: status %d\n", __func__, status);
	return status ? : len;
}

722 723 724
static ssize_t unexport_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
D
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725
{
726 727 728
	long			gpio;
	struct gpio_desc	*desc;
	int			status;
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729

730
	status = kstrtol(buf, 0, &gpio);
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731 732 733
	if (status < 0)
		goto done;

734
	desc = gpio_to_desc(gpio);
D
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735
	/* reject bogus commands (gpio_unexport ignores them) */
736 737 738 739 740 741
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}

	status = -EINVAL;
D
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742 743 744 745 746

	/* No extra locking here; FLAG_SYSFS just signifies that the
	 * request and export were done by on behalf of userspace, so
	 * they may be undone on its behalf too.
	 */
747
	if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
D
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748
		status = 0;
749
		gpiod_free(desc);
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750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
	}
done:
	if (status)
		pr_debug("%s: status %d\n", __func__, status);
	return status ? : len;
}

static struct class_attribute gpio_class_attrs[] = {
	__ATTR(export, 0200, NULL, export_store),
	__ATTR(unexport, 0200, NULL, unexport_store),
	__ATTR_NULL,
};

static struct class gpio_class = {
	.name =		"gpio",
	.owner =	THIS_MODULE,

	.class_attrs =	gpio_class_attrs,
};


/**
772
 * gpiod_export - export a GPIO through sysfs
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773 774 775 776 777 778 779 780 781 782 783 784 785
 * @gpio: gpio to make available, already requested
 * @direction_may_change: true if userspace may change gpio direction
 * Context: arch_initcall or later
 *
 * When drivers want to make a GPIO accessible to userspace after they
 * have requested it -- perhaps while debugging, or as part of their
 * public interface -- they may use this routine.  If the GPIO can
 * change direction (some can't) and the caller allows it, userspace
 * will see "direction" sysfs attribute which may be used to change
 * the gpio's direction.  A "value" attribute will always be provided.
 *
 * Returns zero on success, else an error.
 */
786
int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
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787 788
{
	unsigned long		flags;
R
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789
	int			status;
790
	const char		*ioname = NULL;
R
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791
	struct device		*dev;
792
	int			offset;
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793 794 795 796 797 798 799

	/* can't export until sysfs is available ... */
	if (!gpio_class.p) {
		pr_debug("%s: called too early!\n", __func__);
		return -ENOENT;
	}

800 801
	if (!desc) {
		pr_debug("%s: invalid gpio descriptor\n", __func__);
R
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802 803
		return -EINVAL;
	}
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804 805 806 807

	mutex_lock(&sysfs_lock);

	spin_lock_irqsave(&gpio_lock, flags);
R
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808 809 810 811
	if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
	     test_bit(FLAG_EXPORT, &desc->flags)) {
		spin_unlock_irqrestore(&gpio_lock, flags);
		pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
812
				__func__, desc_to_gpio(desc),
R
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813 814
				test_bit(FLAG_REQUESTED, &desc->flags),
				test_bit(FLAG_EXPORT, &desc->flags));
815 816
		status = -EPERM;
		goto fail_unlock;
D
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817
	}
R
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818 819 820

	if (!desc->chip->direction_input || !desc->chip->direction_output)
		direction_may_change = false;
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821 822
	spin_unlock_irqrestore(&gpio_lock, flags);

823 824 825
	offset = gpio_chip_hwgpio(desc);
	if (desc->chip->names && desc->chip->names[offset])
		ioname = desc->chip->names[offset];
826

R
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827
	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
828 829
			    desc, ioname ? ioname : "gpio%u",
			    desc_to_gpio(desc));
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830 831 832
	if (IS_ERR(dev)) {
		status = PTR_ERR(dev);
		goto fail_unlock;
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833 834
	}

R
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835
	status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
D
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836
	if (status)
R
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837
		goto fail_unregister_device;
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838

R
Ryan Mallon 已提交
839 840 841 842 843 844
	if (direction_may_change) {
		status = device_create_file(dev, &dev_attr_direction);
		if (status)
			goto fail_unregister_device;
	}

845
	if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
R
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846 847 848 849 850
				       !test_bit(FLAG_IS_OUT, &desc->flags))) {
		status = device_create_file(dev, &dev_attr_edge);
		if (status)
			goto fail_unregister_device;
	}
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R
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852 853 854 855 856 857 858 859
	set_bit(FLAG_EXPORT, &desc->flags);
	mutex_unlock(&sysfs_lock);
	return 0;

fail_unregister_device:
	device_unregister(dev);
fail_unlock:
	mutex_unlock(&sysfs_lock);
860 861
	pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
		 status);
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	return status;
}
864
EXPORT_SYMBOL_GPL(gpiod_export);
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865

866
static int match_export(struct device *dev, const void *data)
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{
	return dev_get_drvdata(dev) == data;
}

871
/**
872
 * gpiod_export_link - create a sysfs link to an exported GPIO node
873 874 875 876 877 878 879 880 881
 * @dev: device under which to create symlink
 * @name: name of the symlink
 * @gpio: gpio to create symlink to, already exported
 *
 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
 * node. Caller is responsible for unlinking.
 *
 * Returns zero on success, else an error.
 */
882 883
int gpiod_export_link(struct device *dev, const char *name,
		      struct gpio_desc *desc)
884 885 886
{
	int			status = -EINVAL;

887 888 889 890
	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}
891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {
		struct device *tdev;

		tdev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (tdev != NULL) {
			status = sysfs_create_link(&dev->kobj, &tdev->kobj,
						name);
		} else {
			status = -ENODEV;
		}
	}

	mutex_unlock(&sysfs_lock);

	if (status)
909 910
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
911 912 913

	return status;
}
914
EXPORT_SYMBOL_GPL(gpiod_export_link);
915 916

/**
917
 * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
918 919 920 921 922 923 924 925 926 927
 * @gpio: gpio to change
 * @value: non-zero to use active low, i.e. inverted values
 *
 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
 * The GPIO does not have to be exported yet.  If poll(2) support has
 * been enabled for either rising or falling edge, it will be
 * reconfigured to follow the new polarity.
 *
 * Returns zero on success, else an error.
 */
928
int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
929 930 931 932
{
	struct device		*dev = NULL;
	int			status = -EINVAL;

933 934 935 936
	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}
937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {
		dev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (dev == NULL) {
			status = -ENODEV;
			goto unlock;
		}
	}

	status = sysfs_set_active_low(desc, dev, value);

unlock:
	mutex_unlock(&sysfs_lock);

	if (status)
954 955
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
956 957 958

	return status;
}
959
EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);
960

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961
/**
962
 * gpiod_unexport - reverse effect of gpio_export()
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 * @gpio: gpio to make unavailable
 *
 * This is implicit on gpio_free().
 */
967
void gpiod_unexport(struct gpio_desc *desc)
D
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968
{
969
	int			status = 0;
970
	struct device		*dev = NULL;
D
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971

972
	if (!desc) {
973 974
		pr_warn("%s: invalid GPIO\n", __func__);
		return;
975
	}
D
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976 977 978 979 980 981 982

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {

		dev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (dev) {
983
			gpio_setup_irq(desc, dev, 0);
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984 985 986 987 988 989
			clear_bit(FLAG_EXPORT, &desc->flags);
		} else
			status = -ENODEV;
	}

	mutex_unlock(&sysfs_lock);
990

991 992 993 994
	if (dev) {
		device_unregister(dev);
		put_device(dev);
	}
995

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996
	if (status)
997 998 999
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
}
1000
EXPORT_SYMBOL_GPL(gpiod_unexport);
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1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018

static int gpiochip_export(struct gpio_chip *chip)
{
	int		status;
	struct device	*dev;

	/* Many systems register gpio chips for SOC support very early,
	 * before driver model support is available.  In those cases we
	 * export this later, in gpiolib_sysfs_init() ... here we just
	 * verify that _some_ field of gpio_class got initialized.
	 */
	if (!gpio_class.p)
		return 0;

	/* use chip->base for the ID; it's already known to be unique */
	mutex_lock(&sysfs_lock);
	dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
				"gpiochip%d", chip->base);
1019
	if (!IS_ERR(dev)) {
D
David Brownell 已提交
1020 1021 1022
		status = sysfs_create_group(&dev->kobj,
				&gpiochip_attr_group);
	} else
1023
		status = PTR_ERR(dev);
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1024 1025 1026 1027 1028 1029 1030 1031
	chip->exported = (status == 0);
	mutex_unlock(&sysfs_lock);

	if (status) {
		unsigned long	flags;
		unsigned	gpio;

		spin_lock_irqsave(&gpio_lock, flags);
1032 1033 1034
		gpio = 0;
		while (gpio < chip->ngpio)
			chip->desc[gpio++].chip = NULL;
D
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1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
		spin_unlock_irqrestore(&gpio_lock, flags);

		pr_debug("%s: chip %s status %d\n", __func__,
				chip->label, status);
	}

	return status;
}

static void gpiochip_unexport(struct gpio_chip *chip)
{
	int			status;
	struct device		*dev;

	mutex_lock(&sysfs_lock);
	dev = class_find_device(&gpio_class, NULL, chip, match_export);
	if (dev) {
		put_device(dev);
		device_unregister(dev);
		chip->exported = 0;
		status = 0;
	} else
		status = -ENODEV;
	mutex_unlock(&sysfs_lock);

	if (status)
		pr_debug("%s: chip %s status %d\n", __func__,
				chip->label, status);
}

static int __init gpiolib_sysfs_init(void)
{
	int		status;
	unsigned long	flags;
1069
	struct gpio_chip *chip;
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David Brownell 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081

	status = class_register(&gpio_class);
	if (status < 0)
		return status;

	/* Scan and register the gpio_chips which registered very
	 * early (e.g. before the class_register above was called).
	 *
	 * We run before arch_initcall() so chip->dev nodes can have
	 * registered, and so arch_initcall() can always gpio_export().
	 */
	spin_lock_irqsave(&gpio_lock, flags);
1082
	list_for_each_entry(chip, &gpio_chips, list) {
D
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1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108
		if (!chip || chip->exported)
			continue;

		spin_unlock_irqrestore(&gpio_lock, flags);
		status = gpiochip_export(chip);
		spin_lock_irqsave(&gpio_lock, flags);
	}
	spin_unlock_irqrestore(&gpio_lock, flags);


	return status;
}
postcore_initcall(gpiolib_sysfs_init);

#else
static inline int gpiochip_export(struct gpio_chip *chip)
{
	return 0;
}

static inline void gpiochip_unexport(struct gpio_chip *chip)
{
}

#endif /* CONFIG_GPIO_SYSFS */

1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145
/*
 * Add a new chip to the global chips list, keeping the list of chips sorted
 * by base order.
 *
 * Return -EBUSY if the new chip overlaps with some other chip's integer
 * space.
 */
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
	struct list_head *pos = &gpio_chips;
	struct gpio_chip *_chip;
	int err = 0;

	/* find where to insert our chip */
	list_for_each(pos, &gpio_chips) {
		_chip = list_entry(pos, struct gpio_chip, list);
		/* shall we insert before _chip? */
		if (_chip->base >= chip->base + chip->ngpio)
			break;
	}

	/* are we stepping on the chip right before? */
	if (pos != &gpio_chips && pos->prev != &gpio_chips) {
		_chip = list_entry(pos->prev, struct gpio_chip, list);
		if (_chip->base + _chip->ngpio > chip->base) {
			dev_err(chip->dev,
			       "GPIO integer space overlap, cannot add chip\n");
			err = -EBUSY;
		}
	}

	if (!err)
		list_add_tail(&chip->list, pos);

	return err;
}

1146 1147 1148 1149 1150 1151 1152 1153
/**
 * gpiochip_add() - register a gpio_chip
 * @chip: the chip to register, with chip->base initialized
 * Context: potentially before irqs or kmalloc will work
 *
 * Returns a negative errno if the chip can't be registered, such as
 * because the chip->base is invalid or already associated with a
 * different chip.  Otherwise it returns zero as a success code.
1154
 *
D
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1155 1156 1157 1158 1159
 * When gpiochip_add() is called very early during boot, so that GPIOs
 * can be freely used, the chip->dev device must be registered before
 * the gpio framework's arch_initcall().  Otherwise sysfs initialization
 * for GPIOs will fail rudely.
 *
1160 1161
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
1162 1163 1164 1165 1166 1167
 */
int gpiochip_add(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;
1168
	int		base = chip->base;
1169

T
Trent Piepho 已提交
1170
	if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1171
			&& base >= 0) {
1172 1173 1174 1175 1176 1177
		status = -EINVAL;
		goto fail;
	}

	spin_lock_irqsave(&gpio_lock, flags);

1178 1179 1180 1181
	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
D
David Brownell 已提交
1182
			goto unlock;
1183 1184 1185 1186
		}
		chip->base = base;
	}

1187 1188
	status = gpiochip_add_to_list(chip);

1189
	if (status == 0) {
1190 1191 1192 1193 1194
		chip->desc = &gpio_desc[chip->base];

		for (id = 0; id < chip->ngpio; id++) {
			struct gpio_desc *desc = &chip->desc[id];
			desc->chip = chip;
D
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1195 1196 1197 1198 1199

			/* REVISIT:  most hardware initializes GPIOs as
			 * inputs (often with pullups enabled) so power
			 * usage is minimized.  Linux code should set the
			 * gpio direction first thing; but until it does,
1200
			 * and in case chip->get_direction is not set,
D
David Brownell 已提交
1201 1202
			 * we may expose the wrong direction in sysfs.
			 */
1203
			desc->flags = !chip->direction_input
D
David Brownell 已提交
1204 1205
				? (1 << FLAG_IS_OUT)
				: 0;
1206 1207 1208
		}
	}

1209 1210
	spin_unlock_irqrestore(&gpio_lock, flags);

1211 1212 1213 1214
#ifdef CONFIG_PINCTRL
	INIT_LIST_HEAD(&chip->pin_ranges);
#endif

1215 1216
	of_gpiochip_add(chip);

1217 1218 1219 1220 1221 1222 1223
	if (status)
		goto fail;

	status = gpiochip_export(chip);
	if (status)
		goto fail;

1224
	pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1225 1226 1227
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");

1228
	return 0;
1229 1230 1231

unlock:
	spin_unlock_irqrestore(&gpio_lock, flags);
1232 1233
fail:
	/* failures here can mean systems won't boot... */
1234 1235 1236
	pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");
1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254
	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_add);

/**
 * gpiochip_remove() - unregister a gpio_chip
 * @chip: the chip to unregister
 *
 * A gpio_chip with any GPIOs still requested may not be removed.
 */
int gpiochip_remove(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;

	spin_lock_irqsave(&gpio_lock, flags);

1255
	gpiochip_remove_pin_ranges(chip);
1256 1257
	of_gpiochip_remove(chip);

1258 1259
	for (id = 0; id < chip->ngpio; id++) {
		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
1260 1261 1262 1263 1264
			status = -EBUSY;
			break;
		}
	}
	if (status == 0) {
1265 1266
		for (id = 0; id < chip->ngpio; id++)
			chip->desc[id].chip = NULL;
1267 1268

		list_del(&chip->list);
1269 1270 1271
	}

	spin_unlock_irqrestore(&gpio_lock, flags);
D
David Brownell 已提交
1272 1273 1274 1275

	if (status == 0)
		gpiochip_unexport(chip);

1276 1277 1278 1279
	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290
/**
 * gpiochip_find() - iterator for locating a specific gpio_chip
 * @data: data to pass to match function
 * @callback: Callback function to check gpio_chip
 *
 * Similar to bus_find_device.  It returns a reference to a gpio_chip as
 * determined by a user supplied @match callback.  The callback should return
 * 0 if the device doesn't match and non-zero if it does.  If the callback is
 * non-zero, this function will return to the caller and not iterate over any
 * more gpio_chips.
 */
1291
struct gpio_chip *gpiochip_find(void *data,
1292
				int (*match)(struct gpio_chip *chip,
1293
					     void *data))
1294
{
1295
	struct gpio_chip *chip;
1296 1297 1298
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);
1299 1300
	list_for_each_entry(chip, &gpio_chips, list)
		if (match(chip, data))
1301
			break;
1302 1303 1304 1305

	/* No match? */
	if (&chip->list == &gpio_chips)
		chip = NULL;
1306 1307 1308 1309
	spin_unlock_irqrestore(&gpio_lock, flags);

	return chip;
}
J
Jean Delvare 已提交
1310
EXPORT_SYMBOL_GPL(gpiochip_find);
1311

1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323
static int gpiochip_match_name(struct gpio_chip *chip, void *data)
{
	const char *name = data;

	return !strcmp(chip->label, name);
}

static struct gpio_chip *find_chip_by_name(const char *name)
{
	return gpiochip_find((void *)name, gpiochip_match_name);
}

1324
#ifdef CONFIG_PINCTRL
1325

1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356
/**
 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
 * @pinctrl: the dev_name() of the pin controller to map to
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_group: name of the pin group inside the pin controller
 */
int gpiochip_add_pingroup_range(struct gpio_chip *chip,
			struct pinctrl_dev *pctldev,
			unsigned int gpio_offset, const char *pin_group)
{
	struct gpio_pin_range *pin_range;
	int ret;

	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
		return -ENOMEM;
	}

	/* Use local offset as range ID */
	pin_range->range.id = gpio_offset;
	pin_range->range.gc = chip;
	pin_range->range.name = chip->label;
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->pctldev = pctldev;

	ret = pinctrl_get_group_pins(pctldev, pin_group,
					&pin_range->range.pins,
					&pin_range->range.npins);
1357 1358
	if (ret < 0) {
		kfree(pin_range);
1359
		return ret;
1360
	}
1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374

	pinctrl_add_gpio_range(pctldev, &pin_range->range);

	pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PINGRP %s\n",
		 chip->label, gpio_offset,
		 gpio_offset + pin_range->range.npins - 1,
		 pinctrl_dev_get_devname(pctldev), pin_group);

	list_add_tail(&pin_range->node, &chip->pin_ranges);

	return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);

1375 1376 1377 1378
/**
 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
 * @pinctrl_name: the dev_name() of the pin controller to map to
1379 1380
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
1381 1382 1383
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
1384
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
1385
			   unsigned int gpio_offset, unsigned int pin_offset,
1386
			   unsigned int npins)
1387 1388
{
	struct gpio_pin_range *pin_range;
1389
	int ret;
1390

1391
	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
1392 1393 1394
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
1395
		return -ENOMEM;
1396 1397
	}

1398
	/* Use local offset as range ID */
1399
	pin_range->range.id = gpio_offset;
1400
	pin_range->range.gc = chip;
1401
	pin_range->range.name = chip->label;
1402 1403
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
1404
	pin_range->range.npins = npins;
L
Linus Walleij 已提交
1405
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
1406
			&pin_range->range);
1407
	if (IS_ERR(pin_range->pctldev)) {
1408
		ret = PTR_ERR(pin_range->pctldev);
1409 1410 1411
		pr_err("%s: GPIO chip: could not create pin range\n",
		       chip->label);
		kfree(pin_range);
1412
		return ret;
1413
	}
1414 1415 1416 1417
	pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
		 chip->label, gpio_offset, gpio_offset + npins - 1,
		 pinctl_name,
		 pin_offset, pin_offset + npins - 1);
1418 1419

	list_add_tail(&pin_range->node, &chip->pin_ranges);
1420 1421

	return 0;
1422
}
1423
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
1424

1425 1426 1427 1428
/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
1429 1430 1431 1432 1433 1434 1435 1436
void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
{
	struct gpio_pin_range *pin_range, *tmp;

	list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
		list_del(&pin_range->node);
		pinctrl_remove_gpio_range(pin_range->pctldev,
				&pin_range->range);
1437
		kfree(pin_range);
1438 1439
	}
}
1440 1441 1442
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */
1443

1444 1445 1446 1447
/* These "optional" allocation calls help prevent drivers from stomping
 * on each other, and help provide better diagnostics in debugfs.
 * They're called even less than the "set direction" calls.
 */
1448
static int gpiod_request(struct gpio_desc *desc, const char *label)
1449
{
D
David Brownell 已提交
1450
	struct gpio_chip	*chip;
1451
	int			status = -EPROBE_DEFER;
1452 1453
	unsigned long		flags;

1454
	if (!desc) {
1455 1456
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
1457
	}
1458 1459 1460

	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1461
	chip = desc->chip;
1462 1463
	if (chip == NULL)
		goto done;
1464

D
David Brownell 已提交
1465
	if (!try_module_get(chip->owner))
1466 1467
		goto done;

1468
	/* NOTE:  gpio_request() can be called in early boot,
D
David Brownell 已提交
1469
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1470 1471 1472 1473 1474
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
1475
	} else {
1476
		status = -EBUSY;
D
David Brownell 已提交
1477
		module_put(chip->owner);
M
Magnus Damm 已提交
1478
		goto done;
D
David Brownell 已提交
1479 1480 1481 1482 1483
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1484
		status = chip->request(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1485 1486 1487 1488 1489 1490
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			module_put(chip->owner);
			clear_bit(FLAG_REQUESTED, &desc->flags);
1491
			goto done;
D
David Brownell 已提交
1492
		}
1493
	}
1494 1495 1496
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1497
		gpiod_get_direction(desc);
1498 1499
		spin_lock_irqsave(&gpio_lock, flags);
	}
1500 1501
done:
	if (status)
1502
		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1503
			 desc_to_gpio(desc), label ? : "?", status);
1504 1505 1506
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}
1507 1508 1509 1510 1511

int gpio_request(unsigned gpio, const char *label)
{
	return gpiod_request(gpio_to_desc(gpio), label);
}
1512 1513
EXPORT_SYMBOL_GPL(gpio_request);

1514
static void gpiod_free(struct gpio_desc *desc)
1515 1516
{
	unsigned long		flags;
D
David Brownell 已提交
1517
	struct gpio_chip	*chip;
1518

1519 1520
	might_sleep();

1521
	if (!desc) {
1522 1523 1524 1525
		WARN_ON(extra_checks);
		return;
	}

1526
	gpiod_unexport(desc);
D
David Brownell 已提交
1527

1528 1529
	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1530 1531 1532 1533
	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
1534
			might_sleep_if(chip->can_sleep);
1535
			chip->free(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1536 1537
			spin_lock_irqsave(&gpio_lock, flags);
		}
1538
		desc_set_label(desc, NULL);
1539
		module_put(desc->chip->owner);
1540
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
D
David Brownell 已提交
1541
		clear_bit(FLAG_REQUESTED, &desc->flags);
1542
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1543
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1544
	} else
1545 1546 1547 1548
		WARN_ON(extra_checks);

	spin_unlock_irqrestore(&gpio_lock, flags);
}
1549 1550 1551 1552 1553

void gpio_free(unsigned gpio)
{
	gpiod_free(gpio_to_desc(gpio));
}
1554 1555
EXPORT_SYMBOL_GPL(gpio_free);

1556 1557 1558 1559 1560 1561 1562 1563
/**
 * gpio_request_one - request a single GPIO with initial configuration
 * @gpio:	the GPIO number
 * @flags:	GPIO configuration as specified by GPIOF_*
 * @label:	a literal description string of this GPIO
 */
int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
{
1564
	struct gpio_desc *desc;
1565 1566
	int err;

1567 1568 1569
	desc = gpio_to_desc(gpio);

	err = gpiod_request(desc, label);
1570 1571 1572
	if (err)
		return err;

1573
	if (flags & GPIOF_OPEN_DRAIN)
1574
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1575

1576
	if (flags & GPIOF_OPEN_SOURCE)
1577
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1578

1579
	if (flags & GPIOF_DIR_IN)
1580
		err = gpiod_direction_input(desc);
1581
	else
1582
		err = gpiod_direction_output(desc,
1583 1584
				(flags & GPIOF_INIT_HIGH) ? 1 : 0);

1585
	if (err)
1586 1587 1588
		goto free_gpio;

	if (flags & GPIOF_EXPORT) {
1589
		err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
1590 1591 1592 1593 1594
		if (err)
			goto free_gpio;
	}

	return 0;
1595

1596
 free_gpio:
1597
	gpiod_free(desc);
1598 1599 1600 1601 1602 1603 1604 1605 1606
	return err;
}
EXPORT_SYMBOL_GPL(gpio_request_one);

/**
 * gpio_request_array - request multiple GPIOs in a single call
 * @array:	array of the 'struct gpio'
 * @num:	how many GPIOs in the array
 */
1607
int gpio_request_array(const struct gpio *array, size_t num)
1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629
{
	int i, err;

	for (i = 0; i < num; i++, array++) {
		err = gpio_request_one(array->gpio, array->flags, array->label);
		if (err)
			goto err_free;
	}
	return 0;

err_free:
	while (i--)
		gpio_free((--array)->gpio);
	return err;
}
EXPORT_SYMBOL_GPL(gpio_request_array);

/**
 * gpio_free_array - release multiple GPIOs in a single call
 * @array:	array of the 'struct gpio'
 * @num:	how many GPIOs in the array
 */
1630
void gpio_free_array(const struct gpio *array, size_t num)
1631 1632 1633 1634 1635
{
	while (num--)
		gpio_free((array++)->gpio);
}
EXPORT_SYMBOL_GPL(gpio_free_array);
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651

/**
 * gpiochip_is_requested - return string iff signal was requested
 * @chip: controller managing the signal
 * @offset: of signal within controller's 0..(ngpio - 1) range
 *
 * Returns NULL if the GPIO is not currently requested, else a string.
 * If debugfs support is enabled, the string returned is the label passed
 * to gpio_request(); otherwise it is a meaningless constant.
 *
 * This function is for use by GPIO controller drivers.  The label can
 * help with diagnostics, and knowing that the signal is used as a GPIO
 * can help avoid accidentally multiplexing it to another controller.
 */
const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
{
1652
	struct gpio_desc *desc;
1653

1654
	if (!GPIO_OFFSET_VALID(chip, offset))
1655
		return NULL;
1656 1657 1658

	desc = &chip->desc[offset];

1659
	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1660 1661
		return NULL;
#ifdef CONFIG_DEBUG_FS
1662
	return desc->label;
1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678
#else
	return "?";
#endif
}
EXPORT_SYMBOL_GPL(gpiochip_is_requested);


/* Drivers MUST set GPIO direction before making get/set calls.  In
 * some cases this is done in early boot, before IRQs are enabled.
 *
 * As a rule these aren't called more than once (except for drivers
 * using the open-drain emulation idiom) so these are natural places
 * to accumulate extra debugging checks.  Note that we can't (yet)
 * rely on gpio_request() having been called beforehand.
 */

1679 1680 1681 1682 1683 1684 1685 1686 1687 1688
/**
 * gpiod_direction_input - set the GPIO direction to input
 * @desc:	GPIO to set to input
 *
 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
 * be called safely on it.
 *
 * Return 0 in case of success, else an error code.
 */
int gpiod_direction_input(struct gpio_desc *desc)
1689 1690 1691 1692
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1693
	int			offset;
1694

1695
	if (!desc || !desc->chip) {
1696 1697 1698 1699
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1700 1701
	chip = desc->chip;
	if (!chip->get || !chip->direction_input) {
1702 1703 1704
		gpiod_warn(desc,
			"%s: missing get() or direction_input() operations\n",
			 __func__);
1705 1706 1707
		return -EIO;
	}

1708 1709
	spin_lock_irqsave(&gpio_lock, flags);

1710
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1711 1712
	if (status < 0)
		goto fail;
1713 1714 1715 1716 1717

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

1718
	might_sleep_if(chip->can_sleep);
1719

1720
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1721
	if (status) {
1722
		status = chip->request(chip, offset);
D
David Brownell 已提交
1723
		if (status < 0) {
1724
			gpiod_dbg(desc, "chip request fail, %d\n", status);
D
David Brownell 已提交
1725 1726 1727 1728 1729 1730 1731
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1732
	status = chip->direction_input(chip, offset);
1733 1734
	if (status == 0)
		clear_bit(FLAG_IS_OUT, &desc->flags);
1735

1736
	trace_gpio_direction(desc_to_gpio(desc), 1, status);
D
David Brownell 已提交
1737
lose:
1738 1739 1740
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1741
	if (status)
1742
		gpiod_dbg(desc, "%s status %d\n", __func__, status);
1743 1744
	return status;
}
1745
EXPORT_SYMBOL_GPL(gpiod_direction_input);
1746

1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757
/**
 * gpiod_direction_output - set the GPIO direction to input
 * @desc:	GPIO to set to output
 * @value:	initial output value of the GPIO
 *
 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
 * be called safely on it. The initial value of the output must be specified.
 *
 * Return 0 in case of success, else an error code.
 */
int gpiod_direction_output(struct gpio_desc *desc, int value)
1758 1759 1760 1761
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1762
	int offset;
1763

1764
	if (!desc || !desc->chip) {
1765 1766 1767 1768
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1769 1770 1771 1772 1773 1774 1775 1776
	/* GPIOs used for IRQs shall not be set as output */
	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
		gpiod_err(desc,
			  "%s: tried to set a GPIO tied to an IRQ as output\n",
			  __func__);
		return -EIO;
	}

1777 1778
	/* Open drain pin should not be driven to 1 */
	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
1779
		return gpiod_direction_input(desc);
1780

1781 1782
	/* Open source pin should not be driven to 0 */
	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
1783
		return gpiod_direction_input(desc);
1784

1785 1786
	chip = desc->chip;
	if (!chip->set || !chip->direction_output) {
1787 1788 1789
		gpiod_warn(desc,
		       "%s: missing set() or direction_output() operations\n",
		       __func__);
1790 1791 1792
		return -EIO;
	}

1793 1794
	spin_lock_irqsave(&gpio_lock, flags);

1795
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1796 1797
	if (status < 0)
		goto fail;
1798 1799 1800 1801 1802

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

1803
	might_sleep_if(chip->can_sleep);
1804

1805
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1806
	if (status) {
1807
		status = chip->request(chip, offset);
D
David Brownell 已提交
1808
		if (status < 0) {
1809
			gpiod_dbg(desc, "chip request fail, %d\n", status);
D
David Brownell 已提交
1810 1811 1812 1813 1814 1815 1816
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1817
	status = chip->direction_output(chip, offset, value);
1818 1819
	if (status == 0)
		set_bit(FLAG_IS_OUT, &desc->flags);
1820 1821
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	trace_gpio_direction(desc_to_gpio(desc), 0, status);
D
David Brownell 已提交
1822
lose:
1823 1824 1825
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1826
	if (status)
1827
		gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
1828 1829
	return status;
}
1830
EXPORT_SYMBOL_GPL(gpiod_direction_output);
1831

1832
/**
1833
 * gpiod_set_debounce - sets @debounce time for a @gpio
1834 1835
 * @gpio: the gpio to set debounce time
 * @debounce: debounce time is microseconds
1836 1837 1838
 *
 * returns -ENOTSUPP if the controller does not support setting
 * debounce.
1839
 */
1840
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1841 1842 1843 1844
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1845
	int			offset;
1846

1847
	if (!desc || !desc->chip) {
1848 1849 1850 1851
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1852
	chip = desc->chip;
1853
	if (!chip->set || !chip->set_debounce) {
1854 1855 1856
		gpiod_dbg(desc,
			  "%s: missing set() or set_debounce() operations\n",
			  __func__);
1857
		return -ENOTSUPP;
1858 1859 1860
	}

	spin_lock_irqsave(&gpio_lock, flags);
1861 1862

	status = gpio_ensure_requested(desc);
1863 1864 1865 1866 1867 1868 1869
	if (status < 0)
		goto fail;

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

1870
	might_sleep_if(chip->can_sleep);
1871

1872 1873
	offset = gpio_chip_hwgpio(desc);
	return chip->set_debounce(chip, offset, debounce);
1874 1875 1876

fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1877
	if (status)
1878
		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
1879 1880 1881

	return status;
}
1882
EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1883

1884 1885 1886 1887 1888 1889 1890
/**
 * gpiod_is_active_low - test whether a GPIO is active-low or not
 * @desc: the gpio descriptor to test
 *
 * Returns 1 if the GPIO is active-low, 0 otherwise.
 */
int gpiod_is_active_low(const struct gpio_desc *desc)
1891
{
1892
	return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1893
}
1894
EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917

/* I/O calls are only valid after configuration completed; the relevant
 * "is this a valid GPIO" error checks should already have been done.
 *
 * "Get" operations are often inlinable as reading a pin value register,
 * and masking the relevant bit in that register.
 *
 * When "set" operations are inlinable, they involve writing that mask to
 * one register to set a low value, or a different register to set it high.
 * Otherwise locking is needed, so there may be little value to inlining.
 *
 *------------------------------------------------------------------------
 *
 * IMPORTANT!!!  The hot paths -- get/set value -- assume that callers
 * have requested the GPIO.  That can include implicit requesting by
 * a direction setting call.  Marking a gpio as requested locks its chip
 * in memory, guaranteeing that these table lookups need no more locking
 * and that gpiochip_remove() will fail.
 *
 * REVISIT when debugging, consider adding some instrumentation to ensure
 * that the GPIO was actually requested.
 */

1918
static int _gpiod_get_raw_value(const struct gpio_desc *desc)
1919 1920
{
	struct gpio_chip	*chip;
1921
	int value;
1922
	int offset;
1923

1924 1925 1926 1927
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	value = chip->get ? chip->get(chip, offset) : 0;
	trace_gpio_value(desc_to_gpio(desc), 1, value);
1928
	return value;
1929
}
1930

1931
/**
1932 1933
 * gpiod_get_raw_value() - return a gpio's raw value
 * @desc: gpio whose value will be returned
1934
 *
1935 1936 1937 1938 1939
 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
 * its ACTIVE_LOW status.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
1940
 */
1941
int gpiod_get_raw_value(const struct gpio_desc *desc)
1942
{
1943 1944
	if (!desc)
		return 0;
1945
	/* Should be using gpio_get_value_cansleep() */
1946
	WARN_ON(desc->chip->can_sleep);
1947
	return _gpiod_get_raw_value(desc);
1948
}
1949
EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1950

1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961
/**
 * gpiod_get_value() - return a gpio's value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
 * account.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
 */
int gpiod_get_value(const struct gpio_desc *desc)
1962
{
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973
	int value;
	if (!desc)
		return 0;
	/* Should be using gpio_get_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);

	value = _gpiod_get_raw_value(desc);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;

	return value;
1974
}
1975
EXPORT_SYMBOL_GPL(gpiod_get_value);
1976

1977 1978
/*
 *  _gpio_set_open_drain_value() - Set the open drain gpio's value.
1979
 * @desc: gpio descriptor whose state need to be set.
1980 1981
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
1982
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
1983 1984
{
	int err = 0;
1985 1986 1987
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

1988
	if (value) {
1989
		err = chip->direction_input(chip, offset);
1990
		if (!err)
1991
			clear_bit(FLAG_IS_OUT, &desc->flags);
1992
	} else {
1993
		err = chip->direction_output(chip, offset, 0);
1994
		if (!err)
1995
			set_bit(FLAG_IS_OUT, &desc->flags);
1996
	}
1997
	trace_gpio_direction(desc_to_gpio(desc), value, err);
1998
	if (err < 0)
1999 2000 2001
		gpiod_err(desc,
			  "%s: Error in set_value for open drain err %d\n",
			  __func__, err);
2002 2003
}

2004
/*
2005 2006
 *  _gpio_set_open_source_value() - Set the open source gpio's value.
 * @desc: gpio descriptor whose state need to be set.
2007 2008
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
2009
static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
2010 2011
{
	int err = 0;
2012 2013 2014
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

2015
	if (value) {
2016
		err = chip->direction_output(chip, offset, 1);
2017
		if (!err)
2018
			set_bit(FLAG_IS_OUT, &desc->flags);
2019
	} else {
2020
		err = chip->direction_input(chip, offset);
2021
		if (!err)
2022
			clear_bit(FLAG_IS_OUT, &desc->flags);
2023
	}
2024
	trace_gpio_direction(desc_to_gpio(desc), !value, err);
2025
	if (err < 0)
2026 2027 2028
		gpiod_err(desc,
			  "%s: Error in set_value for open source err %d\n",
			  __func__, err);
2029 2030
}

2031
static void _gpiod_set_raw_value(struct gpio_desc *desc, int value)
2032 2033 2034
{
	struct gpio_chip	*chip;

2035 2036 2037 2038 2039 2040
	chip = desc->chip;
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
		_gpio_set_open_drain_value(desc, value);
	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
		_gpio_set_open_source_value(desc, value);
2041
	else
2042 2043 2044
		chip->set(chip, gpio_chip_hwgpio(desc), value);
}

2045
/**
2046 2047
 * gpiod_set_raw_value() - assign a gpio's raw value
 * @desc: gpio whose value will be assigned
2048 2049
 * @value: value to assign
 *
2050 2051 2052 2053 2054
 * Set the raw value of the GPIO, i.e. the value of its physical line without
 * regard for its ACTIVE_LOW status.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
2055
 */
2056
void gpiod_set_raw_value(struct gpio_desc *desc, int value)
2057
{
2058 2059
	if (!desc)
		return;
2060
	/* Should be using gpio_set_value_cansleep() */
2061
	WARN_ON(desc->chip->can_sleep);
2062
	_gpiod_set_raw_value(desc, value);
2063
}
2064
EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
2065 2066

/**
2067 2068 2069 2070 2071 2072
 * gpiod_set_value() - assign a gpio's value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
 * account
2073
 *
2074 2075
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
2076
 */
2077
void gpiod_set_value(struct gpio_desc *desc, int value)
2078
{
2079
	if (!desc)
2080 2081 2082 2083 2084 2085
		return;
	/* Should be using gpio_set_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;
	_gpiod_set_raw_value(desc, value);
2086
}
2087
EXPORT_SYMBOL_GPL(gpiod_set_value);
2088 2089

/**
2090 2091
 * gpiod_cansleep() - report whether gpio value access may sleep
 * @desc: gpio to check
2092 2093
 *
 */
2094
int gpiod_cansleep(const struct gpio_desc *desc)
2095
{
2096 2097
	if (!desc)
		return 0;
2098
	return desc->chip->can_sleep;
2099
}
2100
EXPORT_SYMBOL_GPL(gpiod_cansleep);
2101

D
David Brownell 已提交
2102
/**
2103 2104
 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
 * @desc: gpio whose IRQ will be returned (already requested)
D
David Brownell 已提交
2105
 *
2106 2107
 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
 * error.
D
David Brownell 已提交
2108
 */
2109
int gpiod_to_irq(const struct gpio_desc *desc)
D
David Brownell 已提交
2110 2111
{
	struct gpio_chip	*chip;
2112
	int			offset;
D
David Brownell 已提交
2113

2114 2115
	if (!desc)
		return -EINVAL;
2116 2117 2118
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
D
David Brownell 已提交
2119
}
2120
EXPORT_SYMBOL_GPL(gpiod_to_irq);
D
David Brownell 已提交
2121

2122 2123 2124 2125 2126 2127 2128 2129 2130 2131
/**
 * gpiod_lock_as_irq() - lock a GPIO to be used as IRQ
 * @gpio: the GPIO line to lock as used for IRQ
 *
 * This is used directly by GPIO drivers that want to lock down
 * a certain GPIO line to be used as IRQs, for example in the
 * .to_irq() callback of their gpio_chip, or in the .irq_enable()
 * of its irq_chip implementation if the GPIO is known from that
 * code.
 */
2132
int gpiod_lock_as_irq(struct gpio_desc *desc)
2133
{
2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
	if (!desc)
		return -EINVAL;

	if (test_bit(FLAG_IS_OUT, &desc->flags)) {
		gpiod_err(desc,
			  "%s: tried to flag a GPIO set as output for IRQ\n",
			  __func__);
		return -EIO;
	}

	set_bit(FLAG_USED_AS_IRQ, &desc->flags);
	return 0;
2146
}
2147
EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);
2148

2149 2150 2151 2152 2153
int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
	return gpiod_lock_as_irq(gpiochip_offset_to_desc(chip, offset));
}
EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
2154

2155 2156 2157 2158 2159 2160
/**
 * gpiod_unlock_as_irq() - unlock a GPIO used as IRQ
 * @gpio: the GPIO line to unlock from IRQ usage
 *
 * This is used directly by GPIO drivers that want to indicate
 * that a certain GPIO is no longer used exclusively for IRQ.
2161
 */
2162
void gpiod_unlock_as_irq(struct gpio_desc *desc)
2163 2164 2165
{
	if (!desc)
		return;
2166

2167 2168
	clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
}
2169
EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);
2170 2171 2172 2173 2174 2175

void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
	return gpiod_unlock_as_irq(gpiochip_offset_to_desc(chip, offset));
}
EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
2176

2177 2178 2179 2180 2181 2182 2183 2184
/**
 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
 * its ACTIVE_LOW status.
 *
 * This function is to be called from contexts that can sleep.
2185
 */
2186
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
2187 2188
{
	might_sleep_if(extra_checks);
2189 2190
	if (!desc)
		return 0;
2191
	return _gpiod_get_raw_value(desc);
2192
}
2193
EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
2194

2195 2196 2197 2198 2199 2200 2201 2202 2203 2204
/**
 * gpiod_get_value_cansleep() - return a gpio's value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
 * account.
 *
 * This function is to be called from contexts that can sleep.
 */
int gpiod_get_value_cansleep(const struct gpio_desc *desc)
2205
{
2206
	int value;
2207 2208

	might_sleep_if(extra_checks);
2209 2210
	if (!desc)
		return 0;
2211 2212 2213 2214 2215

	value = _gpiod_get_raw_value(desc);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;

2216
	return value;
2217
}
2218
EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
2219

2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230
/**
 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the raw value of the GPIO, i.e. the value of its physical line without
 * regard for its ACTIVE_LOW status.
 *
 * This function is to be called from contexts that can sleep.
 */
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
2231
{
2232
	might_sleep_if(extra_checks);
2233 2234
	if (!desc)
		return;
2235
	_gpiod_set_raw_value(desc, value);
2236
}
2237
EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
2238

2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249
/**
 * gpiod_set_value_cansleep() - assign a gpio's value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
 * account
 *
 * This function is to be called from contexts that can sleep.
 */
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
2250 2251
{
	might_sleep_if(extra_checks);
2252 2253
	if (!desc)
		return;
2254 2255 2256 2257

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;
	_gpiod_set_raw_value(desc, value);
2258
}
2259
EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
2260

2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
/**
 * gpiod_add_table() - register GPIO device consumers
 * @table: array of consumers to register
 * @num: number of consumers in table
 */
void gpiod_add_table(struct gpiod_lookup *table, size_t size)
{
	mutex_lock(&gpio_lookup_lock);

	while (size--) {
		list_add_tail(&table->list, &gpio_lookup_list);
		table++;
	}

	mutex_unlock(&gpio_lookup_lock);
}

#ifdef CONFIG_OF
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
2280 2281
				      unsigned int idx,
				      enum gpio_lookup_flags *flags)
2282 2283 2284 2285 2286 2287 2288
{
	char prop_name[32]; /* 32 is max size of property name */
	enum of_gpio_flags of_flags;
	struct gpio_desc *desc;

	if (con_id)
		snprintf(prop_name, 32, "%s-gpios", con_id);
2289
	else
2290 2291 2292 2293 2294 2295 2296 2297 2298
		snprintf(prop_name, 32, "gpios");

	desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
					&of_flags);

	if (IS_ERR(desc))
		return desc;

	if (of_flags & OF_GPIO_ACTIVE_LOW)
2299
		*flags |= GPIO_ACTIVE_LOW;
2300 2301 2302 2303 2304

	return desc;
}
#else
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
2305 2306
				      unsigned int idx,
				      enum gpio_lookup_flags *flags)
2307 2308
{
	return ERR_PTR(-ENODEV);
2309
}
2310
#endif
2311

2312
static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
2313 2314
					unsigned int idx,
					enum gpio_lookup_flags *flags)
2315
{
2316 2317 2318 2319 2320 2321 2322 2323
	struct acpi_gpio_info info;
	struct gpio_desc *desc;

	desc = acpi_get_gpiod_by_index(dev, idx, &info);
	if (IS_ERR(desc))
		return desc;

	if (info.gpioint && info.active_low)
2324
		*flags |= GPIO_ACTIVE_LOW;
2325 2326

	return desc;
2327 2328
}

2329
static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
2330 2331
				    unsigned int idx,
				    enum gpio_lookup_flags *flags)
2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370
{
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct gpio_desc *desc = ERR_PTR(-ENODEV);
	unsigned int match, best = 0;
	struct gpiod_lookup *p;

	mutex_lock(&gpio_lookup_lock);

	list_for_each_entry(p, &gpio_lookup_list, list) {
		match = 0;

		if (p->dev_id) {
			if (!dev_id || strcmp(p->dev_id, dev_id))
				continue;

			match += 2;
		}

		if (p->con_id) {
			if (!con_id || strcmp(p->con_id, con_id))
				continue;

			match += 1;
		}

		if (p->idx != idx)
			continue;

		if (match > best) {
			struct gpio_chip *chip;

			chip = find_chip_by_name(p->chip_label);

			if (!chip) {
				dev_warn(dev, "cannot find GPIO chip %s\n",
					 p->chip_label);
				continue;
			}

2371
			if (chip->ngpio <= p->chip_hwnum) {
2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420
				dev_warn(dev, "GPIO chip %s has %d GPIOs\n",
					 chip->label, chip->ngpio);
				continue;
			}

			desc = gpio_to_desc(chip->base + p->chip_hwnum);
			*flags = p->flags;

			if (match != 3)
				best = match;
			else
				break;
		}
	}

	mutex_unlock(&gpio_lookup_lock);

	return desc;
}

/**
 * gpio_get - obtain a GPIO for a given GPIO function
 * @dev:	GPIO consumer
 * @con_id:	function within the GPIO consumer
 *
 * Return the GPIO descriptor corresponding to the function con_id of device
 * dev, or an IS_ERR() condition if an error occured.
 */
struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id)
{
	return gpiod_get_index(dev, con_id, 0);
}
EXPORT_SYMBOL_GPL(gpiod_get);

/**
 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
 * @dev:	GPIO consumer
 * @con_id:	function within the GPIO consumer
 * @idx:	index of the GPIO to obtain in the consumer
 *
 * This variant of gpiod_get() allows to access GPIOs other than the first
 * defined one for functions that define several GPIOs.
 *
 * Return a valid GPIO descriptor, or an IS_ERR() condition in case of error.
 */
struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
					       const char *con_id,
					       unsigned int idx)
{
2421
	struct gpio_desc *desc = NULL;
2422
	int status;
2423
	enum gpio_lookup_flags flags = 0;
2424 2425 2426 2427 2428 2429 2430

	dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);

	/* Using device tree? */
	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
		dev_dbg(dev, "using device tree for GPIO lookup\n");
		desc = of_find_gpio(dev, con_id, idx, &flags);
2431 2432 2433
	} else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
		dev_dbg(dev, "using ACPI for GPIO lookup\n");
		desc = acpi_find_gpio(dev, con_id, idx, &flags);
2434 2435 2436 2437 2438 2439 2440 2441
	}

	/*
	 * Either we are not using DT or ACPI, or their lookup did not return
	 * a result. In that case, use platform lookup as a fallback.
	 */
	if (!desc || IS_ERR(desc)) {
		struct gpio_desc *pdesc;
2442
		dev_dbg(dev, "using lookup tables for GPIO lookup");
2443 2444 2445 2446
		pdesc = gpiod_find(dev, con_id, idx, &flags);
		/* If used as fallback, do not replace the previous error */
		if (!IS_ERR(pdesc) || !desc)
			desc = pdesc;
2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458
	}

	if (IS_ERR(desc)) {
		dev_warn(dev, "lookup for GPIO %s failed\n", con_id);
		return desc;
	}

	status = gpiod_request(desc, con_id);

	if (status < 0)
		return ERR_PTR(status);

2459
	if (flags & GPIO_ACTIVE_LOW)
2460
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
2461 2462 2463 2464
	if (flags & GPIO_OPEN_DRAIN)
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
	if (flags & GPIO_OPEN_SOURCE)
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478

	return desc;
}
EXPORT_SYMBOL_GPL(gpiod_get_index);

/**
 * gpiod_put - dispose of a GPIO descriptor
 * @desc:	GPIO descriptor to dispose of
 *
 * No descriptor can be used after gpiod_put() has been called on it.
 */
void gpiod_put(struct gpio_desc *desc)
{
	gpiod_free(desc);
2479
}
2480
EXPORT_SYMBOL_GPL(gpiod_put);
2481 2482 2483 2484 2485 2486 2487

#ifdef CONFIG_DEBUG_FS

static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
	unsigned		i;
	unsigned		gpio = chip->base;
2488
	struct gpio_desc	*gdesc = &chip->desc[0];
2489
	int			is_out;
2490
	int			is_irq;
2491 2492 2493 2494 2495

	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
		if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
			continue;

2496
		gpiod_get_direction(gdesc);
2497
		is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2498 2499
		is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
		seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
2500 2501 2502 2503
			gpio, gdesc->label,
			is_out ? "out" : "in ",
			chip->get
				? (chip->get(chip, i) ? "hi" : "lo")
2504 2505
				: "?  ",
			is_irq ? "IRQ" : "   ");
2506 2507 2508 2509
		seq_printf(s, "\n");
	}
}

2510
static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2511
{
2512
	unsigned long flags;
2513
	struct gpio_chip *chip = NULL;
2514
	loff_t index = *pos;
2515

2516
	s->private = "";
2517

2518
	spin_lock_irqsave(&gpio_lock, flags);
2519
	list_for_each_entry(chip, &gpio_chips, list)
2520 2521
		if (index-- == 0) {
			spin_unlock_irqrestore(&gpio_lock, flags);
2522
			return chip;
2523
		}
2524
	spin_unlock_irqrestore(&gpio_lock, flags);
2525

2526
	return NULL;
2527 2528 2529 2530
}

static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
2531
	unsigned long flags;
2532 2533 2534
	struct gpio_chip *chip = v;
	void *ret = NULL;

2535
	spin_lock_irqsave(&gpio_lock, flags);
2536 2537 2538 2539
	if (list_is_last(&chip->list, &gpio_chips))
		ret = NULL;
	else
		ret = list_entry(chip->list.next, struct gpio_chip, list);
2540
	spin_unlock_irqrestore(&gpio_lock, flags);
2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573

	s->private = "\n";
	++*pos;

	return ret;
}

static void gpiolib_seq_stop(struct seq_file *s, void *v)
{
}

static int gpiolib_seq_show(struct seq_file *s, void *v)
{
	struct gpio_chip *chip = v;
	struct device *dev;

	seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
			chip->base, chip->base + chip->ngpio - 1);
	dev = chip->dev;
	if (dev)
		seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
			dev_name(dev));
	if (chip->label)
		seq_printf(s, ", %s", chip->label);
	if (chip->can_sleep)
		seq_printf(s, ", can sleep");
	seq_printf(s, ":\n");

	if (chip->dbg_show)
		chip->dbg_show(s, chip);
	else
		gpiolib_dbg_show(s, chip);

2574 2575 2576
	return 0;
}

2577 2578 2579 2580 2581 2582 2583
static const struct seq_operations gpiolib_seq_ops = {
	.start = gpiolib_seq_start,
	.next = gpiolib_seq_next,
	.stop = gpiolib_seq_stop,
	.show = gpiolib_seq_show,
};

2584 2585
static int gpiolib_open(struct inode *inode, struct file *file)
{
2586
	return seq_open(file, &gpiolib_seq_ops);
2587 2588
}

2589
static const struct file_operations gpiolib_operations = {
2590
	.owner		= THIS_MODULE,
2591 2592 2593
	.open		= gpiolib_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2594
	.release	= seq_release,
2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606
};

static int __init gpiolib_debugfs_init(void)
{
	/* /sys/kernel/debug/gpio */
	(void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
				NULL, NULL, &gpiolib_operations);
	return 0;
}
subsys_initcall(gpiolib_debugfs_init);

#endif	/* DEBUG_FS */