linux-kernel - [PATCH 5/5] leds: core: Use set_brightness

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Message-id: <1442400464-27367-6-git-send-email-j.anaszewski@samsung.com>
Date:	Wed, 16 Sep 2015 12:47:44 +0200
From:	Jacek Anaszewski <j.anaszewski@...sung.com>
To:	linux-leds@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, andrew@...n.ch,
	sakari.ailus@...ux.intel.com, stsp@...rs.sourceforge.net,
	pavel@....cz, ospite@...denti.unina.it, davem@...emloft.net,
	linus.walleij@...aro.org, ricardo.ribalda@...il.com,
	p.meerwald@...-electronic.com,
	Jacek Anaszewski <j.anaszewski@...sung.com>
Subject: [PATCH 5/5] leds: core: Use set_brightness_work for the blocking op

This patch makes LED core capable of setting brightness for drivers
that implement brightness_set_blocking op. It removes from LED class
drivers responsibility for using work queues on their own.

In order to achieve this set_brightness_delayed callback is being
modified to call newly added __led_set_brightness helper instead of
led_set_brightness_async.

led_set_brightness_async function didn't set brightness in an
asynchronous way in all cases. It was mistakenly assuming that all
LED subsystem drivers used work queue in their brightness_set op,
whereas only half of them did that. Since it has no users now,
it is being removed.

Signed-off-by: Jacek Anaszewski <j.anaszewski@...sung.com>
---
 drivers/leds/led-core.c |   22 +++++++++++++++++++++-
 drivers/leds/leds.h     |   10 ----------
 include/linux/leds.h    |    2 +-
 3 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index fe6c2df..d8649f1 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -25,6 +25,22 @@ EXPORT_SYMBOL_GPL(leds_list_lock);
 LIST_HEAD(leds_list);
 EXPORT_SYMBOL_GPL(leds_list);
 
+static int __led_set_brightness(struct led_classdev *led_cdev,
+				enum led_brightness brightness)
+{
+	int ret = 0;
+
+	if (led_cdev->brightness_set)
+		led_cdev->brightness_set(led_cdev, led_cdev->brightness);
+	else if (led_cdev->brightness_set_blocking)
+		ret = led_cdev->brightness_set_blocking(led_cdev,
+							led_cdev->brightness);
+	else
+		return -EINVAL;
+
+	return ret;
+}
+
 static void led_timer_function(unsigned long data)
 {
 	struct led_classdev *led_cdev = (void *)data;
@@ -83,6 +99,7 @@ static void set_brightness_delayed(struct work_struct *ws)
 {
 	struct led_classdev *led_cdev =
 		container_of(ws, struct led_classdev, set_brightness_work);
+	int ret;
 
 	if (led_cdev->flags & LED_BLINK_DISABLE) {
 		led_cdev->delayed_set_value = LED_OFF;
@@ -90,7 +107,10 @@ static void set_brightness_delayed(struct work_struct *ws)
 		led_cdev->flags &= ~LED_BLINK_DISABLE;
 	}
 
-	led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
+	ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
+	if (ret < 0)
+		dev_err(led_cdev->dev,
+			"Setting an LED's brightness failed (%d)\n", ret);
 }
 
 static void led_set_software_blink(struct led_classdev *led_cdev,
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index 11520eb..04b8e41 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -16,16 +16,6 @@
 #include <linux/rwsem.h>
 #include <linux/leds.h>
 
-static inline void led_set_brightness_async(struct led_classdev *led_cdev,
-					enum led_brightness value)
-{
-	value = min(value, led_cdev->max_brightness);
-	led_cdev->brightness = value;
-
-	if (!(led_cdev->flags & LED_SUSPENDED))
-		led_cdev->brightness_set(led_cdev, value);
-}
-
 static inline int led_set_brightness_sync(struct led_classdev *led_cdev,
 					enum led_brightness value)
 {
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 9f850e6..ae3c178 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -155,7 +155,7 @@ extern void led_blink_set_oneshot(struct led_classdev *led_cdev,
  *
  * Set an LED's brightness, and, if necessary, cancel the
  * software blink timer that implements blinking when the
- * hardware doesn't.
+ * hardware doesn't. This function is guaranteed not to sleep.
  */
 extern void led_set_brightness(struct led_classdev *led_cdev,
 			       enum led_brightness brightness);
-- 
1.7.9.5

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