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gpiolib: add a second blocking notifier to struct gpio_device

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Add a new blocking notifier to struct gpio_device and use it to notify
subscribers about the GPIO device being unregistered from the device
model.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
This commit is contained in:
Bartosz Golaszewski 2023-08-17 13:59:05 +02:00
parent e82bbd6761
commit a067419ba7
3 changed files with 5 additions and 0 deletions
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1
drivers/gpio/gpiolib-cdev.c
View File

@ -2748,4 +2748,5 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
void gpiolib_cdev_unregister(struct gpio_device *gdev)
{
cdev_device_del(&gdev->chrdev, &gdev->dev);
blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
}

1
drivers/gpio/gpiolib.c
View File

@ -848,6 +848,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
spin_unlock_irqrestore(&gpio_lock, flags);
BLOCKING_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
init_rwsem(&gdev->sem);
#ifdef CONFIG_PINCTRL

3
drivers/gpio/gpiolib.h
View File

@ -41,6 +41,8 @@
* @list: links gpio_device:s together for traversal
* @line_state_notifier: used to notify subscribers about lines being
* requested, released or reconfigured
* @device_notifier: used to notify character device wait queues about the GPIO
* device being unregistered
* @sem: protects the structure from a NULL-pointer dereference of @chip by
* user-space operations when the device gets unregistered during
* a hot-unplug event
@ -65,6 +67,7 @@ struct gpio_device {
void *data;
struct list_head list;
struct blocking_notifier_head line_state_notifier;
struct blocking_notifier_head device_notifier;
struct rw_semaphore sem;
#ifdef CONFIG_PINCTRL