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

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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: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250704-gpio-sysfs-chip-export-v4-7-9289d8758243@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2025-07-04 14:58:54 +02:00
parent f7d4fb62d0
commit 1cd53df733
1 changed files with 44 additions and 16 deletions
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60
drivers/gpio/gpiolib-sysfs.c
View file

@ -42,7 +42,10 @@ enum {
}; };
struct gpiod_data { struct gpiod_data {
struct list_head list;
struct gpio_desc *desc; struct gpio_desc *desc;
struct device *dev;
struct mutex mutex; struct mutex mutex;
struct kernfs_node *value_kn; struct kernfs_node *value_kn;
@ -62,6 +65,7 @@ struct gpiod_data {
}; };
struct gpiodev_data { struct gpiodev_data {
struct list_head exported_lines;
struct gpio_device *gdev; struct gpio_device *gdev;
struct device *cdev_id; /* Class device by GPIO device ID */ struct device *cdev_id; /* Class device by GPIO device ID */
struct device *cdev_base; /* Class device by GPIO base */ 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) int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
{ {
struct gpiodev_data *gdev_data;
struct gpiod_data *desc_data; struct gpiod_data *desc_data;
struct gpio_device *gdev; struct gpio_device *gdev;
struct attribute **attrs; struct attribute **attrs;
struct device *dev;
int status; int status;
/* can't export until sysfs is available ... */ /* 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_group.attrs = desc_data->class_attrs;
desc_data->class_attr_groups[0] = &desc_data->class_attr_group; desc_data->class_attr_groups[0] = &desc_data->class_attr_group;
dev = device_create_with_groups(&gpio_class, &gdev->dev, /*
MKDEV(0, 0), desc_data, * Note: we need to continue passing desc_data here as there's still
desc_data->class_attr_groups, * at least one known user of gpiod_export_link() in the tree. This
"gpio%u", desc_to_gpio(desc)); * function still uses class_find_device() internally.
if (IS_ERR(dev)) { */
status = PTR_ERR(dev); 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(desc_data->dev)) {
status = PTR_ERR(desc_data->dev);
goto err_free_data; 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) { if (!desc_data->value_kn) {
status = -ENODEV; status = -ENODEV;
goto err_unregister_device; 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; return 0;
err_unregister_device: err_unregister_device:
device_unregister(dev); device_unregister(desc_data->dev);
err_free_data: err_free_data:
kfree(desc_data); kfree(desc_data);
err_clear_bit: err_clear_bit:
@ -828,8 +847,9 @@ EXPORT_SYMBOL_GPL(gpiod_export_link);
*/ */
void gpiod_unexport(struct gpio_desc *desc) void gpiod_unexport(struct gpio_desc *desc)
{ {
struct gpiod_data *desc_data; struct gpiod_data *desc_data = NULL;
struct device *dev; struct gpiodev_data *gdev_data;
struct gpio_device *gdev;
if (!desc) { if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__); 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)) if (!test_bit(FLAG_EXPORT, &desc->flags))
return; return;
dev = class_find_device(&gpio_class, NULL, desc, match_export); gdev = gpiod_to_gpio_device(desc);
if (!dev) gdev_data = gdev_get_data(gdev);
if (!gdev_data)
return; return;
desc_data = dev_get_drvdata(dev); list_for_each_entry(desc_data, &gdev_data->exported_lines, list)
if (gpiod_is_equal(desc, desc_data->desc))
break;
if (!desc_data)
return;
list_del(&desc_data->list);
clear_bit(FLAG_EXPORT, &desc->flags); clear_bit(FLAG_EXPORT, &desc->flags);
sysfs_put(desc_data->value_kn); sysfs_put(desc_data->value_kn);
device_unregister(dev); device_unregister(desc_data->dev);
/* /*
* Release irq after deregistration to prevent race with * 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); gpio_sysfs_free_irq(desc_data);
} }
put_device(dev);
mutex_destroy(&desc_data->mutex); mutex_destroy(&desc_data->mutex);
kfree(desc_data); kfree(desc_data);
} }
@ -899,6 +926,7 @@ int gpiochip_sysfs_register(struct gpio_device *gdev)
return -ENOMEM; return -ENOMEM;
data->gdev = gdev; data->gdev = gdev;
INIT_LIST_HEAD(&data->exported_lines);
guard(mutex)(&sysfs_lock); guard(mutex)(&sysfs_lock);