leds: core: avoid error message when a USB LED device is unplugged

When a USB LED device is unplugged the remove call chain calls
led_classdev_unregister which tries to switch the LED off.
As the device has been removed already this results in a ENODEV
error message in dmesg.
Avoid this error message by ignoring ENODEV in calls from
led_classdev_unregister if the LED device is flagged as pluggable.

Therefore a new flag LED_HW_PLUGGABLE was introduced which should be set by
all LED drivers handling pluggable LED devices (mainly USB LED devices).

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 14139c337312c574c82a98bee4c163834cad6bc5..aa84e5b375931825e71b23f6e2d1eefc7c3bea17 100644 (file)
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -245,6 +245,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
        up_write(&led_cdev->trigger_lock);
 #endif
 
+       led_cdev->flags |= LED_UNREGISTERING;
+
        /* Stop blinking */
        led_stop_software_blink(led_cdev);
 

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 19e1e60dfaa354585ca01e2ffdc2a47f29c49c3b..ad684b6d0b724bc4b249102879c12202f6e6be50 100644 (file)
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -98,7 +98,10 @@ static void set_brightness_delayed(struct work_struct *ws)
                                                led_cdev->delayed_set_value);
        else
                ret = -ENOTSUPP;
-       if (ret < 0)
+       if (ret < 0 &&
+           /* LED HW might have been unplugged, therefore don't warn */
+           !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
+           (led_cdev->flags & LED_HW_PLUGGABLE)))
                dev_err(led_cdev->dev,
                        "Setting an LED's brightness failed (%d)\n", ret);
 }

diff --git a/include/linux/leds.h b/include/linux/leds.h
index e3470e732ede8a99125b8407c06428d97c8a7af6..f203a8f89d30d0f3e214b43d2c72efea1bdad9f9 100644 (file)
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -39,6 +39,7 @@ struct led_classdev {
 
        /* Lower 16 bits reflect status */
 #define LED_SUSPENDED          (1 << 0)
+#define LED_UNREGISTERING      (1 << 1)
        /* Upper 16 bits reflect control information */
 #define LED_CORE_SUSPENDRESUME (1 << 16)
 #define LED_BLINK_ONESHOT      (1 << 17)
@@ -48,6 +49,7 @@ struct led_classdev {
 #define LED_BLINK_DISABLE      (1 << 21)
 #define LED_SYSFS_DISABLE      (1 << 22)
 #define LED_DEV_CAP_FLASH      (1 << 23)
+#define LED_HW_PLUGGABLE       (1 << 24)
 
        /* Set LED brightness level
         * Must not sleep. Use brightness_set_blocking for drivers