[PATCH v2 03/12] leds: core: Add two new LED_BLINK_ flags

From: Jacek Anaszewski
Date: Mon Sep 28 2015 - 09:07:44 EST


This patch adds LED_BLINK_BRIGHTNESS_CHANGE flag to indicate that blink
brightness has changed, and LED_BLINK_DISABLE flag to indicate that
blinking deactivation has been requested. In order to use the flags
led_timer_function and set_brightness_delayed callbacks as well as
led_set_brightness function are being modified. The main goal of these
modifications is to prepare set_brightness_work for extension of the
scope of its responsibilities.

Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
---
drivers/leds/led-core.c | 36 ++++++++++++++++++++++++++----------
include/linux/leds.h | 10 ++++++----
2 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index ee9309e..7cf5924 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -44,18 +44,18 @@ static void led_timer_function(unsigned long data)
brightness = led_get_brightness(led_cdev);
if (!brightness) {
/* Time to switch the LED on. */
- if (led_cdev->delayed_set_value) {
- led_cdev->blink_brightness =
- led_cdev->delayed_set_value;
- led_cdev->delayed_set_value = 0;
- }
brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
} else {
/* Store the current brightness value to be able
* to restore it when the delay_off period is over.
+ * Do it only if there is no pending blink brightness
+ * change, to avoid overwriting the new value.
*/
- led_cdev->blink_brightness = brightness;
+ if (!(led_cdev->flags & LED_BLINK_BRIGHTNESS_CHANGE))
+ led_cdev->blink_brightness = brightness;
+ else
+ led_cdev->flags &= ~LED_BLINK_BRIGHTNESS_CHANGE;
brightness = LED_OFF;
delay = led_cdev->blink_delay_off;
}
@@ -84,7 +84,11 @@ static void set_brightness_delayed(struct work_struct *ws)
struct led_classdev *led_cdev =
container_of(ws, struct led_classdev, set_brightness_work);

- led_stop_software_blink(led_cdev);
+ if (led_cdev->flags & LED_BLINK_DISABLE) {
+ led_cdev->delayed_set_value = LED_OFF;
+ led_stop_software_blink(led_cdev);
+ led_cdev->flags &= ~LED_BLINK_DISABLE;
+ }

led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
}
@@ -192,11 +196,23 @@ void led_set_brightness(struct led_classdev *led_cdev,
{
int ret = 0;

- /* delay brightness if soft-blink is active */
+ /*
+ * In case blinking is on delay brightness setting
+ * until the next timer tick.
+ */
if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
- led_cdev->delayed_set_value = brightness;
- if (brightness == LED_OFF)
+ /*
+ * If we need to disable soft blinking delegate this to the
+ * work queue task to avoid problems in case we are called
+ * from hard irq context.
+ */
+ if (brightness == LED_OFF) {
+ led_cdev->flags |= LED_BLINK_DISABLE;
schedule_work(&led_cdev->set_brightness_work);
+ } else {
+ led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE;
+ led_cdev->blink_brightness = brightness;
+ }
return;
}

diff --git a/include/linux/leds.h b/include/linux/leds.h
index b122eea..84521e5 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -44,10 +44,12 @@ 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_DISABLE (1 << 20)
-#define SET_BRIGHTNESS_ASYNC (1 << 21)
-#define SET_BRIGHTNESS_SYNC (1 << 22)
-#define LED_DEV_CAP_FLASH (1 << 23)
+#define LED_BLINK_BRIGHTNESS_CHANGE (1 << 20)
+#define LED_BLINK_DISABLE (1 << 21)
+#define LED_SYSFS_DISABLE (1 << 22)
+#define SET_BRIGHTNESS_ASYNC (1 << 23)
+#define SET_BRIGHTNESS_SYNC (1 << 24)
+#define LED_DEV_CAP_FLASH (1 << 25)

/* Set LED brightness level */
/* Must not sleep, use a workqueue if needed */
--
1.7.9.5

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