gpiolib.c 64.1 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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#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)
{
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	if (offset >= chip->ngpio)
		return ERR_PTR(-EINVAL);
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	return &chip->desc[offset];
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}
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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
#ifdef CONFIG_PINCTRL
1313

1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 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 1357 1358 1359 1360
/**
 * 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);
	if (ret < 0)
		return ret;

	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);

1361 1362 1363 1364
/**
 * 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
1365 1366
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
1367 1368 1369
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
1370
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
1371
			   unsigned int gpio_offset, unsigned int pin_offset,
1372
			   unsigned int npins)
1373 1374
{
	struct gpio_pin_range *pin_range;
1375
	int ret;
1376

1377
	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
1378 1379 1380
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
1381
		return -ENOMEM;
1382 1383
	}

1384
	/* Use local offset as range ID */
1385
	pin_range->range.id = gpio_offset;
1386
	pin_range->range.gc = chip;
1387
	pin_range->range.name = chip->label;
1388 1389
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
1390
	pin_range->range.npins = npins;
L
Linus Walleij 已提交
1391
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
1392
			&pin_range->range);
1393
	if (IS_ERR(pin_range->pctldev)) {
1394
		ret = PTR_ERR(pin_range->pctldev);
1395 1396 1397
		pr_err("%s: GPIO chip: could not create pin range\n",
		       chip->label);
		kfree(pin_range);
1398
		return ret;
1399
	}
1400 1401 1402 1403
	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);
1404 1405

	list_add_tail(&pin_range->node, &chip->pin_ranges);
1406 1407

	return 0;
1408
}
1409
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
1410

1411 1412 1413 1414
/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
1415 1416 1417 1418 1419 1420 1421 1422
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);
1423
		kfree(pin_range);
1424 1425
	}
}
1426 1427 1428
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */
1429

1430 1431 1432 1433
/* 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.
 */
1434
static int gpiod_request(struct gpio_desc *desc, const char *label)
1435
{
D
David Brownell 已提交
1436
	struct gpio_chip	*chip;
1437
	int			status = -EPROBE_DEFER;
1438 1439
	unsigned long		flags;

1440
	if (!desc) {
1441 1442
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
1443
	}
1444 1445 1446

	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1447
	chip = desc->chip;
1448 1449
	if (chip == NULL)
		goto done;
1450

D
David Brownell 已提交
1451
	if (!try_module_get(chip->owner))
1452 1453
		goto done;

1454
	/* NOTE:  gpio_request() can be called in early boot,
D
David Brownell 已提交
1455
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1456 1457 1458 1459 1460
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
1461
	} else {
1462
		status = -EBUSY;
D
David Brownell 已提交
1463
		module_put(chip->owner);
M
Magnus Damm 已提交
1464
		goto done;
D
David Brownell 已提交
1465 1466 1467 1468 1469
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1470
		status = chip->request(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1471 1472 1473 1474 1475 1476
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			module_put(chip->owner);
			clear_bit(FLAG_REQUESTED, &desc->flags);
1477
			goto done;
D
David Brownell 已提交
1478
		}
1479
	}
1480 1481 1482
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1483
		gpiod_get_direction(desc);
1484 1485
		spin_lock_irqsave(&gpio_lock, flags);
	}
1486 1487
done:
	if (status)
1488
		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1489
			 desc_to_gpio(desc), label ? : "?", status);
1490 1491 1492
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}
1493 1494 1495 1496 1497

int gpio_request(unsigned gpio, const char *label)
{
	return gpiod_request(gpio_to_desc(gpio), label);
}
1498 1499
EXPORT_SYMBOL_GPL(gpio_request);

1500
static void gpiod_free(struct gpio_desc *desc)
1501 1502
{
	unsigned long		flags;
D
David Brownell 已提交
1503
	struct gpio_chip	*chip;
1504

1505 1506
	might_sleep();

1507
	if (!desc) {
1508 1509 1510 1511
		WARN_ON(extra_checks);
		return;
	}

1512
	gpiod_unexport(desc);
D
David Brownell 已提交
1513

1514 1515
	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1516 1517 1518 1519
	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
1520
			might_sleep_if(chip->can_sleep);
1521
			chip->free(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1522 1523
			spin_lock_irqsave(&gpio_lock, flags);
		}
1524
		desc_set_label(desc, NULL);
1525
		module_put(desc->chip->owner);
1526
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
D
David Brownell 已提交
1527
		clear_bit(FLAG_REQUESTED, &desc->flags);
1528
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1529
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1530
	} else
1531 1532 1533 1534
		WARN_ON(extra_checks);

	spin_unlock_irqrestore(&gpio_lock, flags);
}
1535 1536 1537 1538 1539

void gpio_free(unsigned gpio)
{
	gpiod_free(gpio_to_desc(gpio));
}
1540 1541
EXPORT_SYMBOL_GPL(gpio_free);

1542 1543 1544 1545 1546 1547 1548 1549
/**
 * 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)
{
1550
	struct gpio_desc *desc;
1551 1552
	int err;

1553 1554 1555
	desc = gpio_to_desc(gpio);

	err = gpiod_request(desc, label);
1556 1557 1558
	if (err)
		return err;

1559
	if (flags & GPIOF_OPEN_DRAIN)
1560
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1561

1562
	if (flags & GPIOF_OPEN_SOURCE)
1563
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1564

1565
	if (flags & GPIOF_DIR_IN)
1566
		err = gpiod_direction_input(desc);
1567
	else
1568
		err = gpiod_direction_output(desc,
1569 1570
				(flags & GPIOF_INIT_HIGH) ? 1 : 0);

1571
	if (err)
1572 1573 1574
		goto free_gpio;

	if (flags & GPIOF_EXPORT) {
1575
		err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
1576 1577 1578 1579 1580
		if (err)
			goto free_gpio;
	}

	return 0;
1581

1582
 free_gpio:
1583
	gpiod_free(desc);
1584 1585 1586 1587 1588 1589 1590 1591 1592
	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
 */
1593
int gpio_request_array(const struct gpio *array, size_t num)
1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615
{
	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
 */
1616
void gpio_free_array(const struct gpio *array, size_t num)
1617 1618 1619 1620 1621
{
	while (num--)
		gpio_free((array++)->gpio);
}
EXPORT_SYMBOL_GPL(gpio_free_array);
1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637

/**
 * 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)
{
1638
	struct gpio_desc *desc;
1639

1640
	if (!GPIO_OFFSET_VALID(chip, offset))
1641
		return NULL;
1642 1643 1644

	desc = &chip->desc[offset];

1645
	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1646 1647
		return NULL;
#ifdef CONFIG_DEBUG_FS
1648
	return desc->label;
1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664
#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.
 */

1665 1666 1667 1668 1669 1670 1671 1672 1673 1674
/**
 * 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)
1675 1676 1677 1678
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1679
	int			offset;
1680

1681
	if (!desc || !desc->chip) {
1682 1683 1684 1685
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1686 1687
	chip = desc->chip;
	if (!chip->get || !chip->direction_input) {
1688 1689 1690
		gpiod_warn(desc,
			"%s: missing get() or direction_input() operations\n",
			 __func__);
1691 1692 1693
		return -EIO;
	}

1694 1695
	spin_lock_irqsave(&gpio_lock, flags);

1696
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1697 1698
	if (status < 0)
		goto fail;
1699 1700 1701 1702 1703

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1704
	might_sleep_if(chip->can_sleep);
1705

1706
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1707
	if (status) {
1708
		status = chip->request(chip, offset);
D
David Brownell 已提交
1709
		if (status < 0) {
1710
			gpiod_dbg(desc, "chip request fail, %d\n", status);
D
David Brownell 已提交
1711 1712 1713 1714 1715 1716 1717
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1718
	status = chip->direction_input(chip, offset);
1719 1720
	if (status == 0)
		clear_bit(FLAG_IS_OUT, &desc->flags);
1721

1722
	trace_gpio_direction(desc_to_gpio(desc), 1, status);
D
David Brownell 已提交
1723
lose:
1724 1725 1726
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1727
	if (status)
1728
		gpiod_dbg(desc, "%s status %d\n", __func__, status);
1729 1730
	return status;
}
1731
EXPORT_SYMBOL_GPL(gpiod_direction_input);
1732

1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743
/**
 * 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)
1744 1745 1746 1747
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1748
	int offset;
1749

1750
	if (!desc || !desc->chip) {
1751 1752 1753 1754
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1755 1756 1757 1758 1759 1760 1761 1762
	/* 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;
	}

1763 1764
	/* Open drain pin should not be driven to 1 */
	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
1765
		return gpiod_direction_input(desc);
1766

1767 1768
	/* Open source pin should not be driven to 0 */
	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
1769
		return gpiod_direction_input(desc);
1770

1771 1772
	chip = desc->chip;
	if (!chip->set || !chip->direction_output) {
1773 1774 1775
		gpiod_warn(desc,
		       "%s: missing set() or direction_output() operations\n",
		       __func__);
1776 1777 1778
		return -EIO;
	}

1779 1780
	spin_lock_irqsave(&gpio_lock, flags);

1781
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1782 1783
	if (status < 0)
		goto fail;
1784 1785 1786 1787 1788

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1789
	might_sleep_if(chip->can_sleep);
1790

1791
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1792
	if (status) {
1793
		status = chip->request(chip, offset);
D
David Brownell 已提交
1794
		if (status < 0) {
1795
			gpiod_dbg(desc, "chip request fail, %d\n", status);
D
David Brownell 已提交
1796 1797 1798 1799 1800 1801 1802
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1803
	status = chip->direction_output(chip, offset, value);
1804 1805
	if (status == 0)
		set_bit(FLAG_IS_OUT, &desc->flags);
1806 1807
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	trace_gpio_direction(desc_to_gpio(desc), 0, status);
D
David Brownell 已提交
1808
lose:
1809 1810 1811
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1812
	if (status)
1813
		gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
1814 1815
	return status;
}
1816
EXPORT_SYMBOL_GPL(gpiod_direction_output);
1817

1818
/**
1819
 * gpiod_set_debounce - sets @debounce time for a @gpio
1820 1821
 * @gpio: the gpio to set debounce time
 * @debounce: debounce time is microseconds
1822 1823 1824
 *
 * returns -ENOTSUPP if the controller does not support setting
 * debounce.
1825
 */
1826
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1827 1828 1829 1830
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1831
	int			offset;
1832

1833
	if (!desc || !desc->chip) {
1834 1835 1836 1837
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1838
	chip = desc->chip;
1839
	if (!chip->set || !chip->set_debounce) {
1840 1841 1842
		gpiod_dbg(desc,
			  "%s: missing set() or set_debounce() operations\n",
			  __func__);
1843
		return -ENOTSUPP;
1844 1845 1846
	}

	spin_lock_irqsave(&gpio_lock, flags);
1847 1848

	status = gpio_ensure_requested(desc);
1849 1850 1851 1852 1853 1854 1855
	if (status < 0)
		goto fail;

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1856
	might_sleep_if(chip->can_sleep);
1857

1858 1859
	offset = gpio_chip_hwgpio(desc);
	return chip->set_debounce(chip, offset, debounce);
1860 1861 1862

fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1863
	if (status)
1864
		gpiod_dbg(desc, "%s: status %d\n", __func__, status);
1865 1866 1867

	return status;
}
1868
EXPORT_SYMBOL_GPL(gpiod_set_debounce);
1869

1870 1871 1872 1873 1874 1875 1876
/**
 * 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)
1877
{
1878
	return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
1879
}
1880
EXPORT_SYMBOL_GPL(gpiod_is_active_low);
1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903

/* 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.
 */

1904
static int _gpiod_get_raw_value(const struct gpio_desc *desc)
1905 1906
{
	struct gpio_chip	*chip;
1907
	int value;
1908
	int offset;
1909

1910 1911 1912 1913
	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);
1914
	return value;
1915
}
1916

1917
/**
1918 1919
 * gpiod_get_raw_value() - return a gpio's raw value
 * @desc: gpio whose value will be returned
1920
 *
1921 1922 1923 1924 1925
 * 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.
1926
 */
1927
int gpiod_get_raw_value(const struct gpio_desc *desc)
1928
{
1929 1930
	if (!desc)
		return 0;
1931
	/* Should be using gpio_get_value_cansleep() */
1932
	WARN_ON(desc->chip->can_sleep);
1933
	return _gpiod_get_raw_value(desc);
1934
}
1935
EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
1936

1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947
/**
 * 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)
1948
{
1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959
	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;
1960
}
1961
EXPORT_SYMBOL_GPL(gpiod_get_value);
1962

1963 1964
/*
 *  _gpio_set_open_drain_value() - Set the open drain gpio's value.
1965
 * @desc: gpio descriptor whose state need to be set.
1966 1967
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
1968
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
1969 1970
{
	int err = 0;
1971 1972 1973
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

1974
	if (value) {
1975
		err = chip->direction_input(chip, offset);
1976
		if (!err)
1977
			clear_bit(FLAG_IS_OUT, &desc->flags);
1978
	} else {
1979
		err = chip->direction_output(chip, offset, 0);
1980
		if (!err)
1981
			set_bit(FLAG_IS_OUT, &desc->flags);
1982
	}
1983
	trace_gpio_direction(desc_to_gpio(desc), value, err);
1984
	if (err < 0)
1985 1986 1987
		gpiod_err(desc,
			  "%s: Error in set_value for open drain err %d\n",
			  __func__, err);
1988 1989
}

1990
/*
1991 1992
 *  _gpio_set_open_source_value() - Set the open source gpio's value.
 * @desc: gpio descriptor whose state need to be set.
1993 1994
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
1995
static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
1996 1997
{
	int err = 0;
1998 1999 2000
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

2001
	if (value) {
2002
		err = chip->direction_output(chip, offset, 1);
2003
		if (!err)
2004
			set_bit(FLAG_IS_OUT, &desc->flags);
2005
	} else {
2006
		err = chip->direction_input(chip, offset);
2007
		if (!err)
2008
			clear_bit(FLAG_IS_OUT, &desc->flags);
2009
	}
2010
	trace_gpio_direction(desc_to_gpio(desc), !value, err);
2011
	if (err < 0)
2012 2013 2014
		gpiod_err(desc,
			  "%s: Error in set_value for open source err %d\n",
			  __func__, err);
2015 2016
}

2017
static void _gpiod_set_raw_value(struct gpio_desc *desc, int value)
2018 2019 2020
{
	struct gpio_chip	*chip;

2021 2022 2023 2024 2025 2026
	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);
2027
	else
2028 2029 2030
		chip->set(chip, gpio_chip_hwgpio(desc), value);
}

2031
/**
2032 2033
 * gpiod_set_raw_value() - assign a gpio's raw value
 * @desc: gpio whose value will be assigned
2034 2035
 * @value: value to assign
 *
2036 2037 2038 2039 2040
 * 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.
2041
 */
2042
void gpiod_set_raw_value(struct gpio_desc *desc, int value)
2043
{
2044 2045
	if (!desc)
		return;
2046
	/* Should be using gpio_set_value_cansleep() */
2047
	WARN_ON(desc->chip->can_sleep);
2048
	_gpiod_set_raw_value(desc, value);
2049
}
2050
EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
2051 2052

/**
2053 2054 2055 2056 2057 2058
 * 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
2059
 *
2060 2061
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
2062
 */
2063
void gpiod_set_value(struct gpio_desc *desc, int value)
2064
{
2065
	if (!desc)
2066 2067 2068 2069 2070 2071
		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);
2072
}
2073
EXPORT_SYMBOL_GPL(gpiod_set_value);
2074 2075

/**
2076 2077
 * gpiod_cansleep() - report whether gpio value access may sleep
 * @desc: gpio to check
2078 2079
 *
 */
2080
int gpiod_cansleep(const struct gpio_desc *desc)
2081
{
2082 2083
	if (!desc)
		return 0;
2084
	return desc->chip->can_sleep;
2085
}
2086
EXPORT_SYMBOL_GPL(gpiod_cansleep);
2087

D
David Brownell 已提交
2088
/**
2089 2090
 * 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
2091
 *
2092 2093
 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
 * error.
D
David Brownell 已提交
2094
 */
2095
int gpiod_to_irq(const struct gpio_desc *desc)
D
David Brownell 已提交
2096 2097
{
	struct gpio_chip	*chip;
2098
	int			offset;
D
David Brownell 已提交
2099

2100 2101
	if (!desc)
		return -EINVAL;
2102 2103 2104
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
D
David Brownell 已提交
2105
}
2106
EXPORT_SYMBOL_GPL(gpiod_to_irq);
D
David Brownell 已提交
2107

2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
/**
 * 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.
 */
2118
int gpiod_lock_as_irq(struct gpio_desc *desc)
2119
{
2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131
	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;
2132
}
2133
EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);
2134

2135 2136 2137 2138 2139
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);
2140

2141 2142 2143 2144 2145 2146
/**
 * 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.
2147
 */
2148
void gpiod_unlock_as_irq(struct gpio_desc *desc)
2149 2150 2151
{
	if (!desc)
		return;
2152

2153 2154
	clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
}
2155
EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);
2156 2157 2158 2159 2160 2161

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);
2162

2163 2164 2165 2166 2167 2168 2169 2170
/**
 * 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.
2171
 */
2172
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
2173 2174
{
	might_sleep_if(extra_checks);
2175 2176
	if (!desc)
		return 0;
2177
	return _gpiod_get_raw_value(desc);
2178
}
2179
EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);
2180

2181 2182 2183 2184 2185 2186 2187 2188 2189 2190
/**
 * 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)
2191
{
2192
	int value;
2193 2194

	might_sleep_if(extra_checks);
2195 2196
	if (!desc)
		return 0;
2197 2198 2199 2200 2201

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

2202
	return value;
2203
}
2204
EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);
2205

2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216
/**
 * 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)
2217
{
2218
	might_sleep_if(extra_checks);
2219 2220
	if (!desc)
		return;
2221
	_gpiod_set_raw_value(desc, value);
2222
}
2223
EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
2224

2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
/**
 * 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)
2236 2237
{
	might_sleep_if(extra_checks);
2238 2239
	if (!desc)
		return;
2240 2241 2242 2243

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;
	_gpiod_set_raw_value(desc, value);
2244
}
2245
EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
2246

2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290
/**
 * 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);
}

/*
 * Caller must have a acquired gpio_lookup_lock
 */
static struct gpio_chip *find_chip_by_name(const char *name)
{
	struct gpio_chip *chip = NULL;

	list_for_each_entry(chip, &gpio_lookup_list, list) {
		if (chip->label == NULL)
			continue;
		if (!strcmp(chip->label, name))
			break;
	}

	return chip;
}

#ifdef CONFIG_OF
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
				      unsigned int idx, unsigned long *flags)
{
	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);
2291
	else
2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309
		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)
		*flags |= GPIOF_ACTIVE_LOW;

	return desc;
}
#else
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
				      unsigned int idx, unsigned long *flags)
{
	return ERR_PTR(-ENODEV);
2310
}
2311
#endif
2312

2313 2314
static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
					unsigned int idx, unsigned long *flags)
2315
{
2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326
	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)
		*flags |= GPIOF_ACTIVE_LOW;

	return desc;
2327 2328
}

2329 2330 2331 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 2371 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 2421 2422 2423 2424 2425 2426 2427 2428 2429
static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
				    unsigned int idx, unsigned long *flags)
{
	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;
			}

			if (chip->ngpio >= p->chip_hwnum) {
				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)
{
	struct gpio_desc *desc;
	int status;
	unsigned long flags = 0;

	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);
2430 2431 2432
	} 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);
2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463
	} else {
		dev_dbg(dev, "using lookup tables for GPIO lookup");
		desc = gpiod_find(dev, con_id, idx, &flags);
	}

	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);

	if (flags & GPIOF_ACTIVE_LOW)
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);

	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);
2464
}
2465
EXPORT_SYMBOL_GPL(gpiod_put);
2466 2467 2468 2469 2470 2471 2472

#ifdef CONFIG_DEBUG_FS

static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
	unsigned		i;
	unsigned		gpio = chip->base;
2473
	struct gpio_desc	*gdesc = &chip->desc[0];
2474
	int			is_out;
2475
	int			is_irq;
2476 2477 2478 2479 2480

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

2481
		gpiod_get_direction(gdesc);
2482
		is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2483 2484
		is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
		seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
2485 2486 2487 2488
			gpio, gdesc->label,
			is_out ? "out" : "in ",
			chip->get
				? (chip->get(chip, i) ? "hi" : "lo")
2489 2490
				: "?  ",
			is_irq ? "IRQ" : "   ");
2491 2492 2493 2494
		seq_printf(s, "\n");
	}
}

2495
static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2496
{
2497
	unsigned long flags;
2498
	struct gpio_chip *chip = NULL;
2499
	loff_t index = *pos;
2500

2501
	s->private = "";
2502

2503
	spin_lock_irqsave(&gpio_lock, flags);
2504
	list_for_each_entry(chip, &gpio_chips, list)
2505 2506
		if (index-- == 0) {
			spin_unlock_irqrestore(&gpio_lock, flags);
2507
			return chip;
2508
		}
2509
	spin_unlock_irqrestore(&gpio_lock, flags);
2510

2511
	return NULL;
2512 2513 2514 2515
}

static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
2516
	unsigned long flags;
2517 2518 2519
	struct gpio_chip *chip = v;
	void *ret = NULL;

2520
	spin_lock_irqsave(&gpio_lock, flags);
2521 2522 2523 2524
	if (list_is_last(&chip->list, &gpio_chips))
		ret = NULL;
	else
		ret = list_entry(chip->list.next, struct gpio_chip, list);
2525
	spin_unlock_irqrestore(&gpio_lock, flags);
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558

	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);

2559 2560 2561
	return 0;
}

2562 2563 2564 2565 2566 2567 2568
static const struct seq_operations gpiolib_seq_ops = {
	.start = gpiolib_seq_start,
	.next = gpiolib_seq_next,
	.stop = gpiolib_seq_stop,
	.show = gpiolib_seq_show,
};

2569 2570
static int gpiolib_open(struct inode *inode, struct file *file)
{
2571
	return seq_open(file, &gpiolib_seq_ops);
2572 2573
}

2574
static const struct file_operations gpiolib_operations = {
2575
	.owner		= THIS_MODULE,
2576 2577 2578
	.open		= gpiolib_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2579
	.release	= seq_release,
2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591
};

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 */