Add mechanism for locking LED subsystem sysfs interface. This patch prepares ground for addition of LED Flash Class extension. Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> Cc: Bryan Wu <cooloney@xxxxxxxxx> Cc: Richard Purdie <rpurdie@xxxxxxxxx> --- drivers/leds/led-class.c | 13 +++++++++++-- drivers/leds/led-core.c | 18 ++++++++++++++++++ drivers/leds/led-triggers.c | 11 ++++++++--- include/linux/leds.h | 31 +++++++++++++++++++++++++++++++ 4 files changed, 68 insertions(+), 5 deletions(-) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index aa29198..ea04891 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -45,17 +45,23 @@ static ssize_t brightness_store(struct device *dev, { struct led_classdev *led_cdev = dev_get_drvdata(dev); unsigned long state; - ssize_t ret = -EINVAL; + ssize_t ret; + + mutex_lock(&led_cdev->led_lock); ret = kstrtoul(buf, 10, &state); if (ret) - return ret; + goto unlock; if (state == LED_OFF) led_trigger_remove(led_cdev); __led_set_brightness(led_cdev, state); return size; + ret = size; +unlock: + mutex_unlock(&led_cdev->led_lock); + return ret; } static DEVICE_ATTR_RW(brightness); @@ -219,6 +225,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) #ifdef CONFIG_LEDS_TRIGGERS init_rwsem(&led_cdev->trigger_lock); #endif + mutex_init(&led_cdev->led_lock); /* add to the list of leds */ down_write(&leds_list_lock); list_add_tail(&led_cdev->node, &leds_list); @@ -272,6 +279,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev) down_write(&leds_list_lock); list_del(&led_cdev->node); up_write(&leds_list_lock); + + mutex_destroy(&led_cdev->led_lock); } EXPORT_SYMBOL_GPL(led_classdev_unregister); diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index 71b40d3..4d7cb31 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -126,3 +126,21 @@ void led_set_brightness(struct led_classdev *led_cdev, __led_set_brightness(led_cdev, brightness); } EXPORT_SYMBOL(led_set_brightness); + +/* Caller must ensure led_cdev->led_lock held */ +void led_sysfs_lock(struct led_classdev *led_cdev) +{ + WARN_ON(!mutex_is_locked(&led_cdev->led_lock)); + + led_cdev->flags |= LED_SYSFS_LOCK; +} +EXPORT_SYMBOL_GPL(led_sysfs_lock); + +/* Caller must ensure led_cdev->led_lock held */ +void led_sysfs_unlock(struct led_classdev *led_cdev) +{ + WARN_ON(!mutex_is_locked(&led_cdev->led_lock)); + + led_cdev->flags &= ~LED_SYSFS_LOCK; +} +EXPORT_SYMBOL_GPL(led_sysfs_unlock); diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index c3734f1..0545530 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -37,6 +37,9 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, char trigger_name[TRIG_NAME_MAX]; struct led_trigger *trig; size_t len; + int ret = count; + + mutex_lock(&led_cdev->led_lock); trigger_name[sizeof(trigger_name) - 1] = '\0'; strncpy(trigger_name, buf, sizeof(trigger_name) - 1); @@ -47,7 +50,7 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, if (!strcmp(trigger_name, "none")) { led_trigger_remove(led_cdev); - return count; + goto exit_unlock; } down_read(&triggers_list_lock); @@ -58,12 +61,14 @@ ssize_t led_trigger_store(struct device *dev, struct device_attribute *attr, up_write(&led_cdev->trigger_lock); up_read(&triggers_list_lock); - return count; + goto exit_unlock; } } up_read(&triggers_list_lock); - return -EINVAL; +exit_unlock: + mutex_unlock(&led_cdev->led_lock); + return ret; } EXPORT_SYMBOL_GPL(led_trigger_store); diff --git a/include/linux/leds.h b/include/linux/leds.h index 995f933..da7c6b5 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -13,6 +13,7 @@ #define __LINUX_LEDS_H_INCLUDED #include <linux/list.h> +#include <linux/mutex.h> #include <linux/spinlock.h> #include <linux/rwsem.h> #include <linux/timer.h> @@ -42,6 +43,7 @@ struct led_classdev { #define LED_BLINK_ONESHOT (1 << 17) #define LED_BLINK_ONESHOT_STOP (1 << 18) #define LED_BLINK_INVERT (1 << 19) +#define LED_SYSFS_LOCK (1 << 20) /* Set LED brightness level */ /* Must not sleep, use a workqueue if needed */ @@ -85,6 +87,9 @@ struct led_classdev { /* true if activated - deactivate routine uses it to do cleanup */ bool activated; #endif + + /* Ensures consistent access to the LED Flash Class device */ + struct mutex led_lock; }; extern int led_classdev_register(struct device *parent, @@ -140,6 +145,32 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev, */ extern void led_set_brightness(struct led_classdev *led_cdev, enum led_brightness brightness); +/** + * led_sysfs_lock - lock LED sysfs interface + * @led_cdev: the LED to set + * + * Lock the LED's sysfs interface + */ +extern void led_sysfs_lock(struct led_classdev *led_cdev); + +/** + * led_sysfs_unlock - unlock LED sysfs interface + * @led_cdev: the LED to set + * + * Unlock the LED's sysfs interface + */ +extern void led_sysfs_unlock(struct led_classdev *led_cdev); + +/** + * led_sysfs_is_locked + * @led_cdev: the LED to query + * + * Returns: true if the sysfs interface of the led is locked + */ +static inline bool led_sysfs_is_locked(struct led_classdev *led_cdev) +{ + return led_cdev->flags & LED_SYSFS_LOCK; +} /* * LED Triggers -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html