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Commit 6a4b6b0a authored by Johan Hovold's avatar Johan Hovold Committed by Linus Walleij
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gpio: sysfs: clean up chip class-device handling 



Clean gpio-chip class device registration and deregistration.

The class device is registered when a gpio-chip is added (or from
gpiolib_sysfs_init post-core init call), and deregistered when the chip
is removed.

Store the class device in struct gpio_chip directly rather than do a
class-device lookup on deregistration. This also removes the need for
the exported flag.

Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 3ff74be5

drivers/gpio/gpiolib-sysfs.c

+13 −26
Original line number Diff line number Diff line
@@ -582,7 +582,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 
	mutex_lock(&sysfs_lock);



	/* check if chip is being removed */

	if (!chip || !chip->exported) {

	if (!chip || !chip->cdev) {

		status = -ENODEV;

		goto fail_unlock;

	}
@@ -767,7 +767,6 @@ EXPORT_SYMBOL_GPL(gpiod_unexport); 


int gpiochip_export(struct gpio_chip *chip)

{

	int		status;

	struct device	*dev;



	/* Many systems register gpio chips for SOC support very early,
@@ -783,41 +782,29 @@ int gpiochip_export(struct gpio_chip *chip) 
					chip, gpiochip_groups,

					"gpiochip%d", chip->base);

	if (IS_ERR(dev))

		status = PTR_ERR(dev);

	else

		status = 0;

		return PTR_ERR(dev);



	mutex_lock(&sysfs_lock);

	chip->exported = (status == 0);

	chip->cdev = dev;

	mutex_unlock(&sysfs_lock);



	if (status)

		chip_dbg(chip, "%s: status %d\n", __func__, status);



	return status;

	return 0;

}



void gpiochip_unexport(struct gpio_chip *chip)

{

	int			status;

	struct device		*dev;

	struct gpio_desc *desc;

	unsigned int i;



	dev = class_find_device(&gpio_class, NULL, chip, match_export);

	if (dev) {

		put_device(dev);

		device_unregister(dev);

	if (!chip->cdev)

		return;



	device_unregister(chip->cdev);



	/* prevent further gpiod exports */

	mutex_lock(&sysfs_lock);

		chip->exported = false;

	chip->cdev = NULL;

	mutex_unlock(&sysfs_lock);

		status = 0;

	} else

		status = -ENODEV;



	if (status)

		chip_dbg(chip, "%s: status %d\n", __func__, status);



	/* unregister gpiod class devices owned by sysfs */

	for (i = 0; i < chip->ngpio; i++) {
@@ -845,7 +832,7 @@ static int __init gpiolib_sysfs_init(void) 
	 */

	spin_lock_irqsave(&gpio_lock, flags);

	list_for_each_entry(chip, &gpio_chips, list) {

		if (chip->exported)

		if (chip->cdev)

			continue;



		/*

include/linux/gpio/driver.h

+2 −2
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ struct seq_file; 
 * struct gpio_chip - abstract a GPIO controller

 * @label: for diagnostics

 * @dev: optional device providing the GPIOs

 * @cdev: class device used by sysfs interface (may be NULL)

 * @owner: helps prevent removal of modules exporting active GPIOs

 * @list: links gpio_chips together for traversal

 * @request: optional hook for chip-specific activation, such as
@@ -57,7 +58,6 @@ struct seq_file; 
 *	implies that if the chip supports IRQs, these IRQs need to be threaded

 *	as the chip access may sleep when e.g. reading out the IRQ status

 *	registers.

 * @exported: flags if the gpiochip is exported for use from sysfs. Private.

 * @irq_not_threaded: flag must be set if @can_sleep is set but the

 *	IRQs don't need to be threaded

 *
@@ -74,6 +74,7 @@ struct seq_file; 
struct gpio_chip {

	const char		*label;

	struct device		*dev;

	struct device		*cdev;

	struct module		*owner;

	struct list_head        list;
@@ -109,7 +110,6 @@ struct gpio_chip { 
	const char		*const *names;

	bool			can_sleep;

	bool			irq_not_threaded;

	bool			exported;



#ifdef CONFIG_GPIOLIB_IRQCHIP

	/*