Commit 2a9101e8 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpio: sysfs: use gpio_device_find() to iterate over existing devices 



With the list of GPIO devices now protected with SRCU we can use
gpio_device_find() to traverse it from sysfs.

Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 1f2bcb8c

drivers/gpio/gpiolib-sysfs.c

+23 −23
Original line number Diff line number Diff line
@@ -790,11 +790,29 @@ void gpiochip_sysfs_unregister(struct gpio_device *gdev) 
	}

}



/*

 * We're not really looking for a device - we just want to iterate over the

 * list and call this callback for each GPIO device. This is why this function

 * always returns 0.

 */

static int gpiofind_sysfs_register(struct gpio_chip *gc, const void *data)

{

	struct gpio_device *gdev = gc->gpiodev;

	int ret;



	if (gdev->mockdev)

		return 0;



	ret = gpiochip_sysfs_register(gdev);

	if (ret)

		chip_err(gc, "failed to register the sysfs entry: %d\n", ret);



	return 0;

}



static int __init gpiolib_sysfs_init(void)

{

	int status;

	unsigned long	flags;

	struct gpio_device *gdev;



	status = class_register(&gpio_class);

	if (status < 0)
@@ -806,26 +824,8 @@ static int __init gpiolib_sysfs_init(void) 
	 * We run before arch_initcall() so chip->dev nodes can have

	 * registered, and so arch_initcall() can always gpiod_export().

	 */

	spin_lock_irqsave(&gpio_lock, flags);

	list_for_each_entry(gdev, &gpio_devices, list) {

		if (gdev->mockdev)

			continue;

	(void)gpio_device_find(NULL, gpiofind_sysfs_register);



		/*

		 * TODO we yield gpio_lock here because

		 * gpiochip_sysfs_register() acquires a mutex. This is unsafe

		 * and needs to be fixed.

		 *

		 * Also it would be nice to use gpio_device_find() here so we

		 * can keep gpio_chips local to gpiolib.c, but the yield of

		 * gpio_lock prevents us from doing this.

		 */

		spin_unlock_irqrestore(&gpio_lock, flags);

		status = gpiochip_sysfs_register(gdev);

		spin_lock_irqsave(&gpio_lock, flags);

	}

	spin_unlock_irqrestore(&gpio_lock, flags);



	return status;

	return 0;

}

postcore_initcall(gpiolib_sysfs_init);

drivers/gpio/gpiolib.c

+1 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ DEFINE_SPINLOCK(gpio_lock); 
static DEFINE_MUTEX(gpio_lookup_lock);

static LIST_HEAD(gpio_lookup_list);



LIST_HEAD(gpio_devices);

static LIST_HEAD(gpio_devices);

/* Protects the GPIO device list against concurrent modifications. */

static DEFINE_MUTEX(gpio_devices_lock);

/* Ensures coherence during read-only accesses to the list of GPIO devices. */

drivers/gpio/gpiolib.h

+0 −1
Original line number Diff line number Diff line
@@ -136,7 +136,6 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, 
int gpiod_set_transitory(struct gpio_desc *desc, bool transitory);



extern spinlock_t gpio_lock;

extern struct list_head gpio_devices;



void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action);