Commit 1cd53df7 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpio: sysfs: don't look up exported lines as class devices 



In preparation for adding a parallel, per-chip attribute group for
exported GPIO lines, stop using class device APIs to refer to it in the
code. When unregistering the chip, don't call class_find_device() but
instead store exported lines in a linked list inside the GPIO chip data
object and look it up there.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250704-gpio-sysfs-chip-export-v4-7-9289d8758243@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent f7d4fb62

drivers/gpio/gpiolib-sysfs.c

+44 −16
Original line number Diff line number Diff line
@@ -42,7 +42,10 @@ enum { 
};



struct gpiod_data {

	struct list_head list;



	struct gpio_desc *desc;

	struct device *dev;



	struct mutex mutex;

	struct kernfs_node *value_kn;
@@ -62,6 +65,7 @@ struct gpiod_data { 
};



struct gpiodev_data {

	struct list_head exported_lines;

	struct gpio_device *gdev;

	struct device *cdev_id; /* Class device by GPIO device ID */

	struct device *cdev_base; /* Class device by GPIO base */
@@ -687,10 +691,10 @@ static void gpiod_attr_init(struct device_attribute *dev_attr, const char *name, 
 */

int gpiod_export(struct gpio_desc *desc, bool direction_may_change)

{

	struct gpiodev_data *gdev_data;

	struct gpiod_data *desc_data;

	struct gpio_device *gdev;

	struct attribute **attrs;

	struct device *dev;

	int status;



	/* can't export until sysfs is available ... */
@@ -751,25 +755,40 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 
	desc_data->class_attr_group.attrs = desc_data->class_attrs;

	desc_data->class_attr_groups[0] = &desc_data->class_attr_group;



	dev = device_create_with_groups(&gpio_class, &gdev->dev,

	/*

	 * Note: we need to continue passing desc_data here as there's still

	 * at least one known user of gpiod_export_link() in the tree. This

	 * function still uses class_find_device() internally.

	 */

	desc_data->dev = device_create_with_groups(&gpio_class, &gdev->dev,

						   MKDEV(0, 0), desc_data,

						   desc_data->class_attr_groups,

					"gpio%u", desc_to_gpio(desc));

	if (IS_ERR(dev)) {

		status = PTR_ERR(dev);

						   "gpio%u",

						   desc_to_gpio(desc));

	if (IS_ERR(desc_data->dev)) {

		status = PTR_ERR(desc_data->dev);

		goto err_free_data;

	}



	desc_data->value_kn = sysfs_get_dirent(dev->kobj.sd, "value");

	desc_data->value_kn = sysfs_get_dirent(desc_data->dev->kobj.sd,

						       "value");

	if (!desc_data->value_kn) {

		status = -ENODEV;

		goto err_unregister_device;

	}



	gdev_data = gdev_get_data(gdev);

	if (!gdev_data) {

		status = -ENODEV;

		goto err_unregister_device;

	}



	list_add(&desc_data->list, &gdev_data->exported_lines);



	return 0;



err_unregister_device:

	device_unregister(dev);

	device_unregister(desc_data->dev);

err_free_data:

	kfree(desc_data);

err_clear_bit:
@@ -828,8 +847,9 @@ EXPORT_SYMBOL_GPL(gpiod_export_link); 
 */

void gpiod_unexport(struct gpio_desc *desc)

{

	struct gpiod_data *desc_data;

	struct device *dev;

	struct gpiod_data *desc_data = NULL;

	struct gpiodev_data *gdev_data;

	struct gpio_device *gdev;



	if (!desc) {

		pr_warn("%s: invalid GPIO\n", __func__);
@@ -840,14 +860,22 @@ void gpiod_unexport(struct gpio_desc *desc) 
		if (!test_bit(FLAG_EXPORT, &desc->flags))

			return;



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

		if (!dev)

		gdev = gpiod_to_gpio_device(desc);

		gdev_data = gdev_get_data(gdev);

		if (!gdev_data)

			return;



		list_for_each_entry(desc_data, &gdev_data->exported_lines, list)

			if (gpiod_is_equal(desc, desc_data->desc))

				break;



		if (!desc_data)

			return;



		desc_data = dev_get_drvdata(dev);

		list_del(&desc_data->list);

		clear_bit(FLAG_EXPORT, &desc->flags);

		sysfs_put(desc_data->value_kn);

		device_unregister(dev);

		device_unregister(desc_data->dev);



		/*

		 * Release irq after deregistration to prevent race with
@@ -857,7 +885,6 @@ void gpiod_unexport(struct gpio_desc *desc) 
			gpio_sysfs_free_irq(desc_data);

	}



	put_device(dev);

	mutex_destroy(&desc_data->mutex);

	kfree(desc_data);

}
@@ -899,6 +926,7 @@ int gpiochip_sysfs_register(struct gpio_device *gdev) 
		return -ENOMEM;



	data->gdev = gdev;

	INIT_LIST_HEAD(&data->exported_lines);



	guard(mutex)(&sysfs_lock);