gpiolib.c 53.8 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/idr.h>
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#include <linux/slab.h>
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#define CREATE_TRACE_POINTS
#include <trace/events/gpio.h>
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/* Optional implementation infrastructure for GPIO interfaces.
 *
 * Platforms may want to use this if they tend to use very many GPIOs
 * that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
 *
 * When kernel footprint or instruction count is an issue, simpler
 * implementations may be preferred.  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.
 */


/* 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 */
#define FLAG_ACTIVE_LOW	6	/* sysfs value has active low */
#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 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 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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/*
 * Internal gpiod_* API using descriptors instead of the integer namespace.
 * Most of this should eventually go public.
 */
static int gpiod_request(struct gpio_desc *desc, const char *label);
static void gpiod_free(struct gpio_desc *desc);
static int gpiod_direction_input(struct gpio_desc *desc);
static int gpiod_direction_output(struct gpio_desc *desc, int value);
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static int gpiod_get_direction(const struct gpio_desc *desc);
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static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
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static int gpiod_get_value_cansleep(const struct gpio_desc *desc);
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static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
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static int gpiod_get_value(const struct gpio_desc *desc);
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static void gpiod_set_value(struct gpio_desc *desc, int value);
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static int gpiod_cansleep(const struct gpio_desc *desc);
static int gpiod_to_irq(const struct gpio_desc *desc);
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static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
static int gpiod_export_link(struct device *dev, const char *name,
			     struct gpio_desc *desc);
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value);
static void gpiod_unexport(struct gpio_desc *desc);


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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
 */
static struct gpio_desc *gpio_to_desc(unsigned gpio)
{
	if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
		return NULL;
	else
		return &gpio_desc[gpio];
}

/**
 * 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
 */
static int desc_to_gpio(const struct gpio_desc *desc)
{
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	return desc - &gpio_desc[0];
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}


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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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static 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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/* caller holds gpio_lock *OR* gpio is marked as requested */
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struct gpio_chip *gpio_to_chip(unsigned gpio)
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{
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	return gpiod_to_chip(gpio_to_desc(gpio));
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}

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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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/* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
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static 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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#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 {
		int value;

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

		status = sprintf(buf, "%d\n", value);
	}
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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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			if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
				value = !value;
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			gpiod_set_value_cansleep(desc, value != 0);
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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) {
		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) {
		value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
		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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	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
 */
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static ssize_t export_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
D
David Brownell 已提交
650
{
651 652 653
	long			gpio;
	struct gpio_desc	*desc;
	int			status;
D
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654

655
	status = kstrtol(buf, 0, &gpio);
D
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656 657 658
	if (status < 0)
		goto done;

659
	desc = gpio_to_desc(gpio);
660 661 662 663 664
	/* reject invalid GPIOs */
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}
665

D
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666 667 668 669 670
	/* 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.
	 */

671
	status = gpiod_request(desc, "sysfs");
672 673 674
	if (status < 0) {
		if (status == -EPROBE_DEFER)
			status = -ENODEV;
D
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675
		goto done;
676
	}
677
	status = gpiod_export(desc, true);
D
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678
	if (status < 0)
679
		gpiod_free(desc);
D
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680
	else
681
		set_bit(FLAG_SYSFS, &desc->flags);
D
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682 683 684 685 686 687 688

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

689 690 691
static ssize_t unexport_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
D
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692
{
693 694 695
	long			gpio;
	struct gpio_desc	*desc;
	int			status;
D
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696

697
	status = kstrtol(buf, 0, &gpio);
D
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698 699 700
	if (status < 0)
		goto done;

701
	desc = gpio_to_desc(gpio);
D
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702
	/* reject bogus commands (gpio_unexport ignores them) */
703 704 705 706 707 708
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}

	status = -EINVAL;
D
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709 710 711 712 713

	/* 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.
	 */
714
	if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
D
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		status = 0;
716
		gpiod_free(desc);
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717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752
	}
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,
};


/**
 * gpio_export - export a GPIO through sysfs
 * @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.
 */
753
static int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
D
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754 755
{
	unsigned long		flags;
R
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756
	int			status;
757
	const char		*ioname = NULL;
R
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758
	struct device		*dev;
759
	int			offset;
D
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760 761 762 763 764 765 766

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

767 768
	if (!desc) {
		pr_debug("%s: invalid gpio descriptor\n", __func__);
R
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769 770
		return -EINVAL;
	}
D
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771 772 773 774

	mutex_lock(&sysfs_lock);

	spin_lock_irqsave(&gpio_lock, flags);
R
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775 776 777 778
	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",
779
				__func__, desc_to_gpio(desc),
R
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780 781
				test_bit(FLAG_REQUESTED, &desc->flags),
				test_bit(FLAG_EXPORT, &desc->flags));
782 783
		status = -EPERM;
		goto fail_unlock;
D
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784
	}
R
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785 786 787

	if (!desc->chip->direction_input || !desc->chip->direction_output)
		direction_may_change = false;
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788 789
	spin_unlock_irqrestore(&gpio_lock, flags);

790 791 792
	offset = gpio_chip_hwgpio(desc);
	if (desc->chip->names && desc->chip->names[offset])
		ioname = desc->chip->names[offset];
793

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	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
795 796
			    desc, ioname ? ioname : "gpio%u",
			    desc_to_gpio(desc));
R
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797 798 799
	if (IS_ERR(dev)) {
		status = PTR_ERR(dev);
		goto fail_unlock;
D
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800 801
	}

R
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802
	status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
D
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803
	if (status)
R
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804
		goto fail_unregister_device;
D
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805

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806 807 808 809 810 811
	if (direction_may_change) {
		status = device_create_file(dev, &dev_attr_direction);
		if (status)
			goto fail_unregister_device;
	}

812
	if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
R
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813 814 815 816 817
				       !test_bit(FLAG_IS_OUT, &desc->flags))) {
		status = device_create_file(dev, &dev_attr_edge);
		if (status)
			goto fail_unregister_device;
	}
D
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818

R
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819 820 821 822 823 824 825 826
	set_bit(FLAG_EXPORT, &desc->flags);
	mutex_unlock(&sysfs_lock);
	return 0;

fail_unregister_device:
	device_unregister(dev);
fail_unlock:
	mutex_unlock(&sysfs_lock);
827 828
	pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
		 status);
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829 830
	return status;
}
831 832 833 834 835

int gpio_export(unsigned gpio, bool direction_may_change)
{
	return gpiod_export(gpio_to_desc(gpio), direction_may_change);
}
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836 837
EXPORT_SYMBOL_GPL(gpio_export);

838
static int match_export(struct device *dev, const void *data)
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839 840 841 842
{
	return dev_get_drvdata(dev) == data;
}

843 844 845 846 847 848 849 850 851 852 853
/**
 * gpio_export_link - create a sysfs link to an exported GPIO node
 * @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.
 */
854 855
static int gpiod_export_link(struct device *dev, const char *name,
			     struct gpio_desc *desc)
856 857 858
{
	int			status = -EINVAL;

859 860 861 862
	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}
863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880

	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)
881 882
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
883 884 885 886

	return status;
}

887 888 889 890 891
int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
{
	return gpiod_export_link(dev, name, gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_export_link);
892 893 894 895 896 897 898 899 900 901 902 903 904

/**
 * gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
 * @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.
 */
905
static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
906 907 908 909
{
	struct device		*dev = NULL;
	int			status = -EINVAL;

910 911 912 913
	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}
914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930

	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)
931 932
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
933 934 935

	return status;
}
936 937 938 939 940

int gpio_sysfs_set_active_low(unsigned gpio, int value)
{
	return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
}
941 942
EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);

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943 944 945 946 947 948
/**
 * gpio_unexport - reverse effect of gpio_export()
 * @gpio: gpio to make unavailable
 *
 * This is implicit on gpio_free().
 */
949
static void gpiod_unexport(struct gpio_desc *desc)
D
David Brownell 已提交
950
{
951
	int			status = 0;
952
	struct device		*dev = NULL;
D
David Brownell 已提交
953

954
	if (!desc) {
955 956
		pr_warn("%s: invalid GPIO\n", __func__);
		return;
957
	}
D
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958 959 960 961 962 963 964

	mutex_lock(&sysfs_lock);

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

		dev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (dev) {
965
			gpio_setup_irq(desc, dev, 0);
D
David Brownell 已提交
966 967 968 969 970 971
			clear_bit(FLAG_EXPORT, &desc->flags);
		} else
			status = -ENODEV;
	}

	mutex_unlock(&sysfs_lock);
972

973 974 975 976
	if (dev) {
		device_unregister(dev);
		put_device(dev);
	}
977

D
David Brownell 已提交
978
	if (status)
979 980 981 982 983 984 985
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
}

void gpio_unexport(unsigned gpio)
{
	gpiod_unexport(gpio_to_desc(gpio));
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986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005
}
EXPORT_SYMBOL_GPL(gpio_unexport);

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);
1006
	if (!IS_ERR(dev)) {
D
David Brownell 已提交
1007 1008 1009
		status = sysfs_create_group(&dev->kobj,
				&gpiochip_attr_group);
	} else
1010
		status = PTR_ERR(dev);
D
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1011 1012 1013 1014 1015 1016 1017 1018
	chip->exported = (status == 0);
	mutex_unlock(&sysfs_lock);

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

		spin_lock_irqsave(&gpio_lock, flags);
1019 1020 1021
		gpio = 0;
		while (gpio < chip->ngpio)
			chip->desc[gpio++].chip = NULL;
D
David Brownell 已提交
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
		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;
1056
	struct gpio_chip *chip;
D
David Brownell 已提交
1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068

	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);
1069
	list_for_each_entry(chip, &gpio_chips, list) {
D
David Brownell 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
		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)
{
}

1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114
static inline int gpiod_export(struct gpio_desc *desc,
			       bool direction_may_change)
{
	return -ENOSYS;
}

static inline int gpiod_export_link(struct device *dev, const char *name,
				    struct gpio_desc *desc)
{
	return -ENOSYS;
}

static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
	return -ENOSYS;
}

static inline void gpiod_unexport(struct gpio_desc *desc)
{
}

D
David Brownell 已提交
1115 1116
#endif /* CONFIG_GPIO_SYSFS */

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 1146 1147 1148 1149 1150 1151 1152 1153
/*
 * 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;
}

1154 1155 1156 1157 1158 1159 1160 1161
/**
 * 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.
1162
 *
D
David Brownell 已提交
1163 1164 1165 1166 1167
 * 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.
 *
1168 1169
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
1170 1171 1172 1173 1174 1175
 */
int gpiochip_add(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;
1176
	int		base = chip->base;
1177

T
Trent Piepho 已提交
1178
	if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
1179
			&& base >= 0) {
1180 1181 1182 1183 1184 1185
		status = -EINVAL;
		goto fail;
	}

	spin_lock_irqsave(&gpio_lock, flags);

1186 1187 1188 1189
	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
D
David Brownell 已提交
1190
			goto unlock;
1191 1192 1193 1194
		}
		chip->base = base;
	}

1195 1196
	status = gpiochip_add_to_list(chip);

1197
	if (status == 0) {
1198 1199 1200 1201 1202
		chip->desc = &gpio_desc[chip->base];

		for (id = 0; id < chip->ngpio; id++) {
			struct gpio_desc *desc = &chip->desc[id];
			desc->chip = chip;
D
David Brownell 已提交
1203 1204 1205 1206 1207

			/* 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,
1208
			 * and in case chip->get_direction is not set,
D
David Brownell 已提交
1209 1210
			 * we may expose the wrong direction in sysfs.
			 */
1211
			desc->flags = !chip->direction_input
D
David Brownell 已提交
1212 1213
				? (1 << FLAG_IS_OUT)
				: 0;
1214 1215 1216
		}
	}

1217 1218
	spin_unlock_irqrestore(&gpio_lock, flags);

1219 1220 1221 1222
#ifdef CONFIG_PINCTRL
	INIT_LIST_HEAD(&chip->pin_ranges);
#endif

1223 1224
	of_gpiochip_add(chip);

1225 1226 1227 1228 1229 1230 1231
	if (status)
		goto fail;

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

1232
	pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
1233 1234 1235
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");

1236
	return 0;
1237 1238 1239

unlock:
	spin_unlock_irqrestore(&gpio_lock, flags);
1240 1241
fail:
	/* failures here can mean systems won't boot... */
1242 1243 1244
	pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");
1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262
	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);

1263
	gpiochip_remove_pin_ranges(chip);
1264 1265
	of_gpiochip_remove(chip);

1266 1267
	for (id = 0; id < chip->ngpio; id++) {
		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
1268 1269 1270 1271 1272
			status = -EBUSY;
			break;
		}
	}
	if (status == 0) {
1273 1274
		for (id = 0; id < chip->ngpio; id++)
			chip->desc[id].chip = NULL;
1275 1276

		list_del(&chip->list);
1277 1278 1279
	}

	spin_unlock_irqrestore(&gpio_lock, flags);
D
David Brownell 已提交
1280 1281 1282 1283

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

1284 1285 1286 1287
	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298
/**
 * 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.
 */
1299
struct gpio_chip *gpiochip_find(void *data,
1300
				int (*match)(struct gpio_chip *chip,
1301
					     void *data))
1302
{
1303
	struct gpio_chip *chip;
1304 1305 1306
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);
1307 1308
	list_for_each_entry(chip, &gpio_chips, list)
		if (match(chip, data))
1309
			break;
1310 1311 1312 1313

	/* No match? */
	if (&chip->list == &gpio_chips)
		chip = NULL;
1314 1315 1316 1317
	spin_unlock_irqrestore(&gpio_lock, flags);

	return chip;
}
J
Jean Delvare 已提交
1318
EXPORT_SYMBOL_GPL(gpiochip_find);
1319

1320
#ifdef CONFIG_PINCTRL
1321

1322 1323 1324 1325
/**
 * 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
1326 1327
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
1328 1329 1330
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
1331
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
1332
			   unsigned int gpio_offset, unsigned int pin_offset,
1333
			   unsigned int npins)
1334 1335
{
	struct gpio_pin_range *pin_range;
1336
	int ret;
1337

1338
	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
1339 1340 1341
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
1342
		return -ENOMEM;
1343 1344
	}

1345
	/* Use local offset as range ID */
1346
	pin_range->range.id = gpio_offset;
1347
	pin_range->range.gc = chip;
1348
	pin_range->range.name = chip->label;
1349 1350
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
1351
	pin_range->range.npins = npins;
L
Linus Walleij 已提交
1352
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
1353
			&pin_range->range);
1354
	if (IS_ERR(pin_range->pctldev)) {
1355
		ret = PTR_ERR(pin_range->pctldev);
1356 1357 1358
		pr_err("%s: GPIO chip: could not create pin range\n",
		       chip->label);
		kfree(pin_range);
1359
		return ret;
1360
	}
1361 1362 1363 1364
	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);
1365 1366

	list_add_tail(&pin_range->node, &chip->pin_ranges);
1367 1368

	return 0;
1369
}
1370
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);
1371

1372 1373 1374 1375
/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
1376 1377 1378 1379 1380 1381 1382 1383
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);
1384
		kfree(pin_range);
1385 1386
	}
}
1387 1388 1389
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */
1390

1391 1392 1393 1394
/* 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.
 */
1395
static int gpiod_request(struct gpio_desc *desc, const char *label)
1396
{
D
David Brownell 已提交
1397
	struct gpio_chip	*chip;
1398
	int			status = -EPROBE_DEFER;
1399 1400
	unsigned long		flags;

1401
	if (!desc) {
1402 1403
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
1404
	}
1405 1406 1407

	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1408
	chip = desc->chip;
1409 1410
	if (chip == NULL)
		goto done;
1411

D
David Brownell 已提交
1412
	if (!try_module_get(chip->owner))
1413 1414
		goto done;

1415
	/* NOTE:  gpio_request() can be called in early boot,
D
David Brownell 已提交
1416
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
1417 1418 1419 1420 1421
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
1422
	} else {
1423
		status = -EBUSY;
D
David Brownell 已提交
1424
		module_put(chip->owner);
M
Magnus Damm 已提交
1425
		goto done;
D
David Brownell 已提交
1426 1427 1428 1429 1430
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1431
		status = chip->request(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1432 1433 1434 1435 1436 1437
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			module_put(chip->owner);
			clear_bit(FLAG_REQUESTED, &desc->flags);
1438
			goto done;
D
David Brownell 已提交
1439
		}
1440
	}
1441 1442 1443
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
1444
		gpiod_get_direction(desc);
1445 1446
		spin_lock_irqsave(&gpio_lock, flags);
	}
1447 1448
done:
	if (status)
1449
		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
1450
			 desc_to_gpio(desc), label ? : "?", status);
1451 1452 1453
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}
1454 1455 1456 1457 1458

int gpio_request(unsigned gpio, const char *label)
{
	return gpiod_request(gpio_to_desc(gpio), label);
}
1459 1460
EXPORT_SYMBOL_GPL(gpio_request);

1461
static void gpiod_free(struct gpio_desc *desc)
1462 1463
{
	unsigned long		flags;
D
David Brownell 已提交
1464
	struct gpio_chip	*chip;
1465

1466 1467
	might_sleep();

1468
	if (!desc) {
1469 1470 1471 1472
		WARN_ON(extra_checks);
		return;
	}

1473
	gpiod_unexport(desc);
D
David Brownell 已提交
1474

1475 1476
	spin_lock_irqsave(&gpio_lock, flags);

D
David Brownell 已提交
1477 1478 1479 1480
	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
1481
			might_sleep_if(chip->can_sleep);
1482
			chip->free(chip, gpio_chip_hwgpio(desc));
D
David Brownell 已提交
1483 1484
			spin_lock_irqsave(&gpio_lock, flags);
		}
1485
		desc_set_label(desc, NULL);
1486
		module_put(desc->chip->owner);
1487
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
D
David Brownell 已提交
1488
		clear_bit(FLAG_REQUESTED, &desc->flags);
1489
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
1490
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
1491
	} else
1492 1493 1494 1495
		WARN_ON(extra_checks);

	spin_unlock_irqrestore(&gpio_lock, flags);
}
1496 1497 1498 1499 1500

void gpio_free(unsigned gpio)
{
	gpiod_free(gpio_to_desc(gpio));
}
1501 1502
EXPORT_SYMBOL_GPL(gpio_free);

1503 1504 1505 1506 1507 1508 1509 1510
/**
 * 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)
{
1511
	struct gpio_desc *desc;
1512 1513
	int err;

1514 1515 1516
	desc = gpio_to_desc(gpio);

	err = gpiod_request(desc, label);
1517 1518 1519
	if (err)
		return err;

1520
	if (flags & GPIOF_OPEN_DRAIN)
1521
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
1522

1523
	if (flags & GPIOF_OPEN_SOURCE)
1524
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
1525

1526
	if (flags & GPIOF_DIR_IN)
1527
		err = gpiod_direction_input(desc);
1528
	else
1529
		err = gpiod_direction_output(desc,
1530 1531
				(flags & GPIOF_INIT_HIGH) ? 1 : 0);

1532
	if (err)
1533 1534 1535
		goto free_gpio;

	if (flags & GPIOF_EXPORT) {
1536
		err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
1537 1538 1539 1540 1541
		if (err)
			goto free_gpio;
	}

	return 0;
1542

1543
 free_gpio:
1544
	gpiod_free(desc);
1545 1546 1547 1548 1549 1550 1551 1552 1553
	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
 */
1554
int gpio_request_array(const struct gpio *array, size_t num)
1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
{
	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
 */
1577
void gpio_free_array(const struct gpio *array, size_t num)
1578 1579 1580 1581 1582
{
	while (num--)
		gpio_free((array++)->gpio);
}
EXPORT_SYMBOL_GPL(gpio_free_array);
1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598

/**
 * 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)
{
1599
	struct gpio_desc *desc;
1600

1601
	if (!GPIO_OFFSET_VALID(chip, offset))
1602
		return NULL;
1603 1604 1605

	desc = &chip->desc[offset];

1606
	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
1607 1608
		return NULL;
#ifdef CONFIG_DEBUG_FS
1609
	return desc->label;
1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
#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.
 */

1626
static int gpiod_direction_input(struct gpio_desc *desc)
1627 1628 1629 1630
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1631
	int			offset;
1632

1633
	if (!desc || !desc->chip) {
1634 1635 1636 1637
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1638 1639 1640 1641 1642 1643 1644
	chip = desc->chip;
	if (!chip->get || !chip->direction_input) {
		pr_warn("%s: missing get() or direction_input() operations\n",
			__func__);
		return -EIO;
	}

1645 1646
	spin_lock_irqsave(&gpio_lock, flags);

1647
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1648 1649
	if (status < 0)
		goto fail;
1650 1651 1652 1653 1654

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1655
	might_sleep_if(chip->can_sleep);
1656

1657
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1658
	if (status) {
1659
		status = chip->request(chip, offset);
D
David Brownell 已提交
1660 1661
		if (status < 0) {
			pr_debug("GPIO-%d: chip request fail, %d\n",
1662
				desc_to_gpio(desc), status);
D
David Brownell 已提交
1663 1664 1665 1666 1667 1668 1669
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1670
	status = chip->direction_input(chip, offset);
1671 1672
	if (status == 0)
		clear_bit(FLAG_IS_OUT, &desc->flags);
1673

1674
	trace_gpio_direction(desc_to_gpio(desc), 1, status);
D
David Brownell 已提交
1675
lose:
1676 1677 1678
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1679 1680 1681
	if (status)
		pr_debug("%s: gpio-%d status %d\n", __func__,
			 desc_to_gpio(desc), status);
1682 1683
	return status;
}
1684 1685 1686 1687 1688

int gpio_direction_input(unsigned gpio)
{
	return gpiod_direction_input(gpio_to_desc(gpio));
}
1689 1690
EXPORT_SYMBOL_GPL(gpio_direction_input);

1691
static int gpiod_direction_output(struct gpio_desc *desc, int value)
1692 1693 1694 1695
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1696
	int offset;
1697

1698
	if (!desc || !desc->chip) {
1699 1700 1701 1702
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1703 1704
	/* Open drain pin should not be driven to 1 */
	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
1705
		return gpiod_direction_input(desc);
1706

1707 1708
	/* Open source pin should not be driven to 0 */
	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
1709
		return gpiod_direction_input(desc);
1710

1711 1712 1713 1714 1715 1716 1717
	chip = desc->chip;
	if (!chip->set || !chip->direction_output) {
		pr_warn("%s: missing set() or direction_output() operations\n",
			__func__);
		return -EIO;
	}

1718 1719
	spin_lock_irqsave(&gpio_lock, flags);

1720
	status = gpio_ensure_requested(desc);
D
David Brownell 已提交
1721 1722
	if (status < 0)
		goto fail;
1723 1724 1725 1726 1727

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1728
	might_sleep_if(chip->can_sleep);
1729

1730
	offset = gpio_chip_hwgpio(desc);
D
David Brownell 已提交
1731
	if (status) {
1732
		status = chip->request(chip, offset);
D
David Brownell 已提交
1733 1734
		if (status < 0) {
			pr_debug("GPIO-%d: chip request fail, %d\n",
1735
				desc_to_gpio(desc), status);
D
David Brownell 已提交
1736 1737 1738 1739 1740 1741 1742
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

1743
	status = chip->direction_output(chip, offset, value);
1744 1745
	if (status == 0)
		set_bit(FLAG_IS_OUT, &desc->flags);
1746 1747
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	trace_gpio_direction(desc_to_gpio(desc), 0, status);
D
David Brownell 已提交
1748
lose:
1749 1750 1751
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1752 1753 1754
	if (status)
		pr_debug("%s: gpio-%d status %d\n", __func__,
			 desc_to_gpio(desc), status);
1755 1756
	return status;
}
1757 1758 1759 1760 1761

int gpio_direction_output(unsigned gpio, int value)
{
	return gpiod_direction_output(gpio_to_desc(gpio), value);
}
1762 1763
EXPORT_SYMBOL_GPL(gpio_direction_output);

1764 1765 1766 1767
/**
 * gpio_set_debounce - sets @debounce time for a @gpio
 * @gpio: the gpio to set debounce time
 * @debounce: debounce time is microseconds
1768 1769 1770
 *
 * returns -ENOTSUPP if the controller does not support setting
 * debounce.
1771
 */
1772
static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
1773 1774 1775 1776
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
1777
	int			offset;
1778

1779
	if (!desc || !desc->chip) {
1780 1781 1782 1783
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

1784
	chip = desc->chip;
1785
	if (!chip->set || !chip->set_debounce) {
1786
		pr_debug("%s: missing set() or set_debounce() operations\n",
1787
			__func__);
1788
		return -ENOTSUPP;
1789 1790 1791
	}

	spin_lock_irqsave(&gpio_lock, flags);
1792 1793

	status = gpio_ensure_requested(desc);
1794 1795 1796 1797 1798 1799 1800
	if (status < 0)
		goto fail;

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

	spin_unlock_irqrestore(&gpio_lock, flags);

1801
	might_sleep_if(chip->can_sleep);
1802

1803 1804
	offset = gpio_chip_hwgpio(desc);
	return chip->set_debounce(chip, offset, debounce);
1805 1806 1807

fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
1808 1809 1810
	if (status)
		pr_debug("%s: gpio-%d status %d\n", __func__,
			 desc_to_gpio(desc), status);
1811 1812 1813

	return status;
}
1814 1815 1816 1817 1818

int gpio_set_debounce(unsigned gpio, unsigned debounce)
{
	return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
}
1819
EXPORT_SYMBOL_GPL(gpio_set_debounce);
1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851

/* 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.
 */

/**
 * __gpio_get_value() - return a gpio's value
 * @gpio: gpio whose value will be returned
 * Context: any
 *
 * This is used directly or indirectly to implement gpio_get_value().
 * It returns the zero or nonzero value provided by the associated
 * gpio_chip.get() method; or zero if no such method is provided.
 */
1852
static int gpiod_get_value(const struct gpio_desc *desc)
1853 1854
{
	struct gpio_chip	*chip;
1855
	int value;
1856
	int offset;
1857

1858 1859
	if (!desc)
		return 0;
1860 1861
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
1862
	/* Should be using gpio_get_value_cansleep() */
1863
	WARN_ON(chip->can_sleep);
1864 1865
	value = chip->get ? chip->get(chip, offset) : 0;
	trace_gpio_value(desc_to_gpio(desc), 1, value);
1866
	return value;
1867
}
1868 1869 1870 1871 1872

int __gpio_get_value(unsigned gpio)
{
	return gpiod_get_value(gpio_to_desc(gpio));
}
1873 1874
EXPORT_SYMBOL_GPL(__gpio_get_value);

1875 1876 1877 1878 1879 1880
/*
 *  _gpio_set_open_drain_value() - Set the open drain gpio's value.
 * @gpio: Gpio whose state need to be set.
 * @chip: Gpio chip.
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
1881
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
1882 1883
{
	int err = 0;
1884 1885 1886
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

1887
	if (value) {
1888
		err = chip->direction_input(chip, offset);
1889
		if (!err)
1890
			clear_bit(FLAG_IS_OUT, &desc->flags);
1891
	} else {
1892
		err = chip->direction_output(chip, offset, 0);
1893
		if (!err)
1894
			set_bit(FLAG_IS_OUT, &desc->flags);
1895
	}
1896
	trace_gpio_direction(desc_to_gpio(desc), value, err);
1897 1898
	if (err < 0)
		pr_err("%s: Error in set_value for open drain gpio%d err %d\n",
1899
					__func__, desc_to_gpio(desc), err);
1900 1901
}

1902 1903 1904 1905 1906 1907
/*
 *  _gpio_set_open_source() - Set the open source gpio's value.
 * @gpio: Gpio whose state need to be set.
 * @chip: Gpio chip.
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
1908
static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
1909 1910
{
	int err = 0;
1911 1912 1913
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

1914
	if (value) {
1915
		err = chip->direction_output(chip, offset, 1);
1916
		if (!err)
1917
			set_bit(FLAG_IS_OUT, &desc->flags);
1918
	} else {
1919
		err = chip->direction_input(chip, offset);
1920
		if (!err)
1921
			clear_bit(FLAG_IS_OUT, &desc->flags);
1922
	}
1923
	trace_gpio_direction(desc_to_gpio(desc), !value, err);
1924 1925
	if (err < 0)
		pr_err("%s: Error in set_value for open source gpio%d err %d\n",
1926
					__func__, desc_to_gpio(desc), err);
1927 1928
}

1929 1930 1931 1932 1933 1934 1935 1936 1937
/**
 * __gpio_set_value() - assign a gpio's value
 * @gpio: gpio whose value will be assigned
 * @value: value to assign
 * Context: any
 *
 * This is used directly or indirectly to implement gpio_set_value().
 * It invokes the associated gpio_chip.set() method.
 */
1938
static void gpiod_set_value(struct gpio_desc *desc, int value)
1939 1940 1941
{
	struct gpio_chip	*chip;

1942 1943
	if (!desc)
		return;
1944
	chip = desc->chip;
1945
	/* Should be using gpio_set_value_cansleep() */
1946
	WARN_ON(chip->can_sleep);
1947 1948 1949 1950 1951
	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);
1952
	else
1953 1954 1955 1956 1957 1958
		chip->set(chip, gpio_chip_hwgpio(desc), value);
}

void __gpio_set_value(unsigned gpio, int value)
{
	return gpiod_set_value(gpio_to_desc(gpio), value);
1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
}
EXPORT_SYMBOL_GPL(__gpio_set_value);

/**
 * __gpio_cansleep() - report whether gpio value access will sleep
 * @gpio: gpio in question
 * Context: any
 *
 * This is used directly or indirectly to implement gpio_cansleep().  It
 * returns nonzero if access reading or writing the GPIO value can sleep.
 */
1970
static int gpiod_cansleep(const struct gpio_desc *desc)
1971
{
1972 1973
	if (!desc)
		return 0;
1974
	/* only call this on GPIOs that are valid! */
1975 1976
	return desc->chip->can_sleep;
}
1977

1978 1979 1980
int __gpio_cansleep(unsigned gpio)
{
	return gpiod_cansleep(gpio_to_desc(gpio));
1981 1982 1983
}
EXPORT_SYMBOL_GPL(__gpio_cansleep);

D
David Brownell 已提交
1984 1985 1986 1987 1988 1989 1990 1991 1992
/**
 * __gpio_to_irq() - return the IRQ corresponding to a GPIO
 * @gpio: gpio whose IRQ will be returned (already requested)
 * Context: any
 *
 * This is used directly or indirectly to implement gpio_to_irq().
 * It returns the number of the IRQ signaled by this (input) GPIO,
 * or a negative errno.
 */
1993
static int gpiod_to_irq(const struct gpio_desc *desc)
D
David Brownell 已提交
1994 1995
{
	struct gpio_chip	*chip;
1996
	int			offset;
D
David Brownell 已提交
1997

1998 1999
	if (!desc)
		return -EINVAL;
2000 2001 2002
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
D
David Brownell 已提交
2003 2004
}

2005 2006 2007 2008 2009
int __gpio_to_irq(unsigned gpio)
{
	return gpiod_to_irq(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(__gpio_to_irq);
2010 2011 2012 2013 2014 2015


/* There's no value in making it easy to inline GPIO calls that may sleep.
 * Common examples include ones connected to I2C or SPI chips.
 */

2016
static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
2017 2018
{
	struct gpio_chip	*chip;
2019
	int value;
2020
	int offset;
2021 2022

	might_sleep_if(extra_checks);
2023 2024
	if (!desc)
		return 0;
2025 2026 2027 2028
	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);
2029
	return value;
2030
}
2031 2032 2033 2034 2035

int gpio_get_value_cansleep(unsigned gpio)
{
	return gpiod_get_value_cansleep(gpio_to_desc(gpio));
}
2036 2037
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);

2038
static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
2039 2040 2041 2042
{
	struct gpio_chip	*chip;

	might_sleep_if(extra_checks);
2043 2044
	if (!desc)
		return;
2045 2046 2047 2048 2049 2050
	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);
2051
	else
2052
		chip->set(chip, gpio_chip_hwgpio(desc), value);
2053 2054
}

2055 2056 2057 2058 2059
void gpio_set_value_cansleep(unsigned gpio, int value)
{
	return gpiod_set_value_cansleep(gpio_to_desc(gpio), value);
}
EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
2060 2061 2062 2063 2064 2065 2066

#ifdef CONFIG_DEBUG_FS

static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
	unsigned		i;
	unsigned		gpio = chip->base;
2067
	struct gpio_desc	*gdesc = &chip->desc[0];
2068 2069 2070 2071 2072 2073
	int			is_out;

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

2074
		gpiod_get_direction(gdesc);
2075
		is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
2076
		seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
2077 2078 2079 2080 2081 2082 2083 2084 2085
			gpio, gdesc->label,
			is_out ? "out" : "in ",
			chip->get
				? (chip->get(chip, i) ? "hi" : "lo")
				: "?  ");
		seq_printf(s, "\n");
	}
}

2086
static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
2087
{
2088
	unsigned long flags;
2089
	struct gpio_chip *chip = NULL;
2090
	loff_t index = *pos;
2091

2092
	s->private = "";
2093

2094
	spin_lock_irqsave(&gpio_lock, flags);
2095
	list_for_each_entry(chip, &gpio_chips, list)
2096 2097
		if (index-- == 0) {
			spin_unlock_irqrestore(&gpio_lock, flags);
2098
			return chip;
2099
		}
2100
	spin_unlock_irqrestore(&gpio_lock, flags);
2101

2102
	return NULL;
2103 2104 2105 2106
}

static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
2107
	unsigned long flags;
2108 2109 2110
	struct gpio_chip *chip = v;
	void *ret = NULL;

2111
	spin_lock_irqsave(&gpio_lock, flags);
2112 2113 2114 2115
	if (list_is_last(&chip->list, &gpio_chips))
		ret = NULL;
	else
		ret = list_entry(chip->list.next, struct gpio_chip, list);
2116
	spin_unlock_irqrestore(&gpio_lock, flags);
2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149

	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);

2150 2151 2152
	return 0;
}

2153 2154 2155 2156 2157 2158 2159
static const struct seq_operations gpiolib_seq_ops = {
	.start = gpiolib_seq_start,
	.next = gpiolib_seq_next,
	.stop = gpiolib_seq_stop,
	.show = gpiolib_seq_show,
};

2160 2161
static int gpiolib_open(struct inode *inode, struct file *file)
{
2162
	return seq_open(file, &gpiolib_seq_ops);
2163 2164
}

2165
static const struct file_operations gpiolib_operations = {
2166
	.owner		= THIS_MODULE,
2167 2168 2169
	.open		= gpiolib_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
2170
	.release	= seq_release,
2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182
};

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 */