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Date: Thu, 20 Aug 2015 16:43:33 +0200
From: Jacek Anaszewski <j.anaszewski@...sung.com>
To: linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Jacek Anaszewski <j.anaszewski@...sung.com>,
Andrew Lunn <andrew@...n.ch>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
Pavel Machek <pavel@....cz>,
Stas Sergeev <stsp@...rs.sourceforge.net>
Subject: [PATCH/RFC v6 03/36] leds: Improve asynchronous path of setting
brightness
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. Modify the function to assure
setting brightness asynchronously in all cases by using existing
set_brightness_work.
Aforementioned modifications change the initial purpose of
set_brightness_work which was used for setting brightness only if blink
timer was active. In order to keep this functionality LED_BLINK_DISABLE
flag is being introduced, as well as a 'new_brightness_value' field is
being added to the struct led_classdev. set_brightness_delayed callback
now needs to use led_set_brightness_sync for setting brightness.
All these improvements entail changes in the led_brightness_set function.
Signed-off-by: Jacek Anaszewski <j.anaszewski@...sung.com>
Cc: Andrew Lunn <andrew@...n.ch>
Cc: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Pavel Machek <pavel@....cz>
Cc: Stas Sergeev <stsp@...rs.sourceforge.net>
---
drivers/leds/led-class.c | 13 ++++++++-----
drivers/leds/led-core.c | 20 ++++++++++++++++----
drivers/leds/leds.h | 9 +++------
include/linux/leds.h | 2 ++
4 files changed, 29 insertions(+), 15 deletions(-)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 93a2414..fe11ed8 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -121,10 +121,10 @@ 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) {
+ if (led_cdev->new_brightness_value) {
led_cdev->blink_brightness =
- led_cdev->delayed_set_value;
- led_cdev->delayed_set_value = 0;
+ led_cdev->new_brightness_value;
+ led_cdev->new_brightness_value = 0;
}
brightness = led_cdev->blink_brightness;
delay = led_cdev->blink_delay_on;
@@ -161,9 +161,12 @@ 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_stop_software_blink(led_cdev);
+ led_cdev->flags &= ~LED_BLINK_DISABLE;
+ }
- led_set_brightness_async(led_cdev, led_cdev->delayed_set_value);
+ led_set_brightness_sync(led_cdev, led_cdev->delayed_set_value);
}
/**
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index 3f3b71d..b69271f 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -119,11 +119,23 @@ 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)
- schedule_work(&led_cdev->set_brightness_work);
+ led_cdev->new_brightness_value = brightness;
+
+ /* New brightness will be set on next timer tick. */
+ if (brightness != LED_OFF)
+ return;
+ /*
+ * If need to disable soft blinking delegate this to the
+ * work queue task to avoid problems in case we are
+ * called from hard irq context.
+ */
+ led_cdev->flags |= LED_BLINK_DISABLE;
+ led_set_brightness_async(led_cdev, brightness);
return;
}
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index 1c026c9..ca38f6a 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -17,13 +17,10 @@
#include <linux/leds.h>
static inline void led_set_brightness_async(struct led_classdev *led_cdev,
- enum led_brightness value)
+ 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);
+ led_cdev->delayed_set_value = value;
+ schedule_work(&led_cdev->set_brightness_work);
}
static inline int led_get_brightness(struct led_classdev *led_cdev)
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 2377e0f..8fefe72 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -48,6 +48,7 @@ struct led_classdev {
#define SET_BRIGHTNESS_ASYNC (1 << 21)
#define SET_BRIGHTNESS_SYNC (1 << 22)
#define LED_DEV_CAP_FLASH (1 << 23)
+#define LED_BLINK_DISABLE (1 << 24)
/* Set LED brightness level */
/* Must not sleep, use a workqueue if needed */
@@ -93,6 +94,7 @@ struct led_classdev {
struct work_struct set_brightness_work;
int delayed_set_value;
+ int new_brightness_value;
#ifdef CONFIG_LEDS_TRIGGERS
/* Protects the trigger data below */
--
1.7.9.5
--
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