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authorBartosz Golaszewski <bartosz.golaszewski@linaro.org>2024-10-18 11:10:13 +0200
committerBartosz Golaszewski <bartosz.golaszewski@linaro.org>2024-10-22 08:59:08 +0200
commit7b9b77a8bba9c1fd7bad3310dbf2cf382e1f8c25 (patch)
treee12d5111533a4371ab5f5010d5d4de02cb507a34 /drivers/gpio
parent8c44447bd76109e33a69fccda89c84715fbd5658 (diff)
gpiolib: add a per-gpio_device line state notification workqueue
In order to prepare the line state notification mechanism for working in atomic context as well, add a dedicated, high-priority, ordered workqueue to GPIO device which will be used to queue the events fron any context for them to be emitted always in process context. Reviewed-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20241018-gpio-notify-in-kernel-events-v5-5-c79135e58a1c@linaro.org Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpiolib-cdev.c6
-rw-r--r--drivers/gpio/gpiolib.h4
2 files changed, 10 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 0cba74381687..b242fdb1ad28 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2749,6 +2749,11 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
gdev->chrdev.owner = THIS_MODULE;
gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);
+ gdev->line_state_wq = alloc_ordered_workqueue(dev_name(&gdev->dev),
+ WQ_HIGHPRI);
+ if (!gdev->line_state_wq)
+ return -ENOMEM;
+
ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
if (ret)
return ret;
@@ -2765,6 +2770,7 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
void gpiolib_cdev_unregister(struct gpio_device *gdev)
{
+ destroy_workqueue(gdev->line_state_wq);
cdev_device_del(&gdev->chrdev, &gdev->dev);
blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
}
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 8daba06eb472..8737e1641278 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/srcu.h>
+#include <linux/workqueue.h>
#define GPIOCHIP_NAME "gpiochip"
@@ -44,6 +45,8 @@
* @list: links gpio_device:s together for traversal
* @line_state_notifier: used to notify subscribers about lines being
* requested, released or reconfigured
+ * @line_state_wq: used to emit line state events from a separate thread in
+ * process context
* @device_notifier: used to notify character device wait queues about the GPIO
* device being unregistered
* @srcu: protects the pointer to the underlying GPIO chip
@@ -70,6 +73,7 @@ struct gpio_device {
void *data;
struct list_head list;
struct blocking_notifier_head line_state_notifier;
+ struct workqueue_struct *line_state_wq;
struct blocking_notifier_head device_notifier;
struct srcu_struct srcu;