[PATCH 1/2] leds: use workqueue in led_set_brightness() API internally

From: Bryan Wu
Date: Fri Sep 14 2012 - 03:53:13 EST

The API function led_set_brightness() and __led_set_brightness will
call .brightness_set() function provided by led class drivers. So
.brightness_set() function will run in atomic context, which requires
led class drivers use workqueue in .brightness_set().

Finally, all the led class driver implemented their own workqueue in
.brightness_set(). For those missing this, we will face runtime warning
or error when running it in atomic context.

This patch adds a workqueue in led_set_brightness() internally. LED
class driver doesn't need to care about duplicated workqueue stuff in
their own driver.

Also this patch unified the led_set_brightness() and __led_set_brightness()

Signed-off-by: Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
---
drivers/leds/led-class.c | 23 ++++++++++++-----------
drivers/leds/led-core.c | 15 +++++++--------
drivers/leds/leds.h | 11 ++---------
drivers/leds/ledtrig-backlight.c | 8 ++++----
drivers/leds/ledtrig-default-on.c | 2 +-
drivers/leds/ledtrig-gpio.c | 6 +++---
drivers/leds/ledtrig-heartbeat.c | 2 +-
drivers/leds/ledtrig-oneshot.c | 4 ++--
drivers/leds/ledtrig-transient.c | 8 ++++----
include/linux/leds.h | 12 +++++++-----
10 files changed, 43 insertions(+), 48 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 48cce18..7a3e886 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -53,7 +53,7 @@ static ssize_t led_brightness_store(struct device *dev,

if (state == LED_OFF)
led_trigger_remove(led_cdev);
- __led_set_brightness(led_cdev, state);
+ led_set_brightness(led_cdev, state);

return size;
}
@@ -82,7 +82,7 @@ static void led_timer_function(unsigned long data)
unsigned long delay;

if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
- __led_set_brightness(led_cdev, LED_OFF);
+ led_set_brightness(led_cdev, LED_OFF);
return;
}

@@ -105,7 +105,7 @@ static void led_timer_function(unsigned long data)
delay = led_cdev->blink_delay_off;
}

- __led_set_brightness(led_cdev, brightness);
+ led_set_brightness(led_cdev, brightness);

/* Return in next iteration if led is in one-shot mode and we are in
* the final blink state so that the led is toggled each delay_on +
@@ -124,14 +124,15 @@ static void led_timer_function(unsigned long data)
mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
}

-static void set_brightness_delayed(struct work_struct *ws)
+static void led_set_brightness_work(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->blink_delay_on || led_cdev->blink_delay_off)
+ led_stop_software_blink(led_cdev);

- __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
+ led_cdev->brightness_set(led_cdev, led_cdev->brightness);
}

/**
@@ -141,7 +142,7 @@ static void set_brightness_delayed(struct work_struct *ws)
void led_classdev_suspend(struct led_classdev *led_cdev)
{
led_cdev->flags |= LED_SUSPENDED;
- led_cdev->brightness_set(led_cdev, 0);
+ led_set_brightness(led_cdev, 0);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

@@ -151,7 +152,7 @@ EXPORT_SYMBOL_GPL(led_classdev_suspend);
*/
void led_classdev_resume(struct led_classdev *led_cdev)
{
- led_cdev->brightness_set(led_cdev, led_cdev->brightness);
+ led_set_brightness(led_cdev, led_cdev->brightness);
led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);
@@ -201,7 +202,7 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)

led_update_brightness(led_cdev);

- INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
+ INIT_WORK(&led_cdev->set_brightness_work, led_set_brightness_work);

init_timer(&led_cdev->blink_timer);
led_cdev->blink_timer.function = led_timer_function;
@@ -233,12 +234,12 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
up_write(&led_cdev->trigger_lock);
#endif

- cancel_work_sync(&led_cdev->set_brightness_work);
-
/* Stop blinking */
led_stop_software_blink(led_cdev);
led_set_brightness(led_cdev, LED_OFF);

+ flush_work(&led_cdev->set_brightness_work);
+
device_unregister(led_cdev->dev);

down_write(&leds_list_lock);
diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index ce8921a..c212262 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -45,7 +45,7 @@ static void led_set_software_blink(struct led_classdev *led_cdev,

/* never off - just set to brightness */
if (!delay_off) {
- __led_set_brightness(led_cdev, led_cdev->blink_brightness);
+ led_set_brightness(led_cdev, led_cdev->blink_brightness);
return;
}

@@ -114,13 +114,12 @@ EXPORT_SYMBOL_GPL(led_stop_software_blink);
void led_set_brightness(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
- /* delay brightness setting if need to stop soft-blink timer */
- if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) {
- led_cdev->delayed_set_value = brightness;
- schedule_work(&led_cdev->set_brightness_work);
- return;
- }
+ if (brightness > led_cdev->max_brightness)
+ brightness = led_cdev->max_brightness;

- __led_set_brightness(led_cdev, brightness);
+ led_cdev->brightness = brightness;
+
+ if (!(led_cdev->flags & LED_SUSPENDED))
+ schedule_work(&led_cdev->set_brightness_work);
}
EXPORT_SYMBOL(led_set_brightness);
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index 4c50365..745bf06 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -17,15 +17,8 @@
#include <linux/rwsem.h>
#include <linux/leds.h>

-static inline void __led_set_brightness(struct led_classdev *led_cdev,
- enum led_brightness value)
-{
- if (value > led_cdev->max_brightness)
- value = led_cdev->max_brightness;
- led_cdev->brightness = value;
- if (!(led_cdev->flags & LED_SUSPENDED))
- led_cdev->brightness_set(led_cdev, value);
-}
+void led_set_brightness(struct led_classdev *led_cdev,
+ enum led_brightness value);

static inline int led_get_brightness(struct led_classdev *led_cdev)
{
diff --git a/drivers/leds/ledtrig-backlight.c b/drivers/leds/ledtrig-backlight.c
index b941685..e272686 100644
--- a/drivers/leds/ledtrig-backlight.c
+++ b/drivers/leds/ledtrig-backlight.c
@@ -46,9 +46,9 @@ static int fb_notifier_callback(struct notifier_block *p,

if ((n->old_status == UNBLANK) ^ n->invert) {
n->brightness = led->brightness;
- __led_set_brightness(led, LED_OFF);
+ led_set_brightness(led, LED_OFF);
} else {
- __led_set_brightness(led, n->brightness);
+ led_set_brightness(led, n->brightness);
}

n->old_status = new_status;
@@ -87,9 +87,9 @@ static ssize_t bl_trig_invert_store(struct device *dev,

/* After inverting, we need to update the LED. */
if ((n->old_status == BLANK) ^ n->invert)
- __led_set_brightness(led, LED_OFF);
+ led_set_brightness(led, LED_OFF);
else
- __led_set_brightness(led, n->brightness);
+ led_set_brightness(led, n->brightness);

return num;
}
diff --git a/drivers/leds/ledtrig-default-on.c b/drivers/leds/ledtrig-default-on.c
index eac1f1b..a4ef54b 100644
--- a/drivers/leds/ledtrig-default-on.c
+++ b/drivers/leds/ledtrig-default-on.c
@@ -19,7 +19,7 @@

static void defon_trig_activate(struct led_classdev *led_cdev)
{
- __led_set_brightness(led_cdev, led_cdev->max_brightness);
+ led_set_brightness(led_cdev, led_cdev->max_brightness);
}

static struct led_trigger defon_led_trigger = {
diff --git a/drivers/leds/ledtrig-gpio.c b/drivers/leds/ledtrig-gpio.c
index ba215dc..f057c10 100644
--- a/drivers/leds/ledtrig-gpio.c
+++ b/drivers/leds/ledtrig-gpio.c
@@ -54,12 +54,12 @@ static void gpio_trig_work(struct work_struct *work)

if (tmp) {
if (gpio_data->desired_brightness)
- __led_set_brightness(gpio_data->led,
+ led_set_brightness(gpio_data->led,
gpio_data->desired_brightness);
else
- __led_set_brightness(gpio_data->led, LED_FULL);
+ led_set_brightness(gpio_data->led, LED_FULL);
} else {
- __led_set_brightness(gpio_data->led, LED_OFF);
+ led_set_brightness(gpio_data->led, LED_OFF);
}
}

diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
index 1edc746..a019fbb 100644
--- a/drivers/leds/ledtrig-heartbeat.c
+++ b/drivers/leds/ledtrig-heartbeat.c
@@ -74,7 +74,7 @@ static void led_heartbeat_function(unsigned long data)
break;
}

- __led_set_brightness(led_cdev, brightness);
+ led_set_brightness(led_cdev, brightness);
mod_timer(&heartbeat_data->timer, jiffies + delay);
}

diff --git a/drivers/leds/ledtrig-oneshot.c b/drivers/leds/ledtrig-oneshot.c
index 2c029aa..2b10b28 100644
--- a/drivers/leds/ledtrig-oneshot.c
+++ b/drivers/leds/ledtrig-oneshot.c
@@ -63,9 +63,9 @@ static ssize_t led_invert_store(struct device *dev,
oneshot_data->invert = !!state;

if (oneshot_data->invert)
- __led_set_brightness(led_cdev, LED_FULL);
+ led_set_brightness(led_cdev, LED_FULL);
else
- __led_set_brightness(led_cdev, LED_OFF);
+ led_set_brightness(led_cdev, LED_OFF);

return size;
}
diff --git a/drivers/leds/ledtrig-transient.c b/drivers/leds/ledtrig-transient.c
index 398f104..83179f4 100644
--- a/drivers/leds/ledtrig-transient.c
+++ b/drivers/leds/ledtrig-transient.c
@@ -41,7 +41,7 @@ static void transient_timer_function(unsigned long data)
struct transient_trig_data *transient_data = led_cdev->trigger_data;

transient_data->activate = 0;
- __led_set_brightness(led_cdev, transient_data->restore_state);
+ led_set_brightness(led_cdev, transient_data->restore_state);
}

static ssize_t transient_activate_show(struct device *dev,
@@ -72,7 +72,7 @@ static ssize_t transient_activate_store(struct device *dev,
if (state == 0 && transient_data->activate == 1) {
del_timer(&transient_data->timer);
transient_data->activate = state;
- __led_set_brightness(led_cdev, transient_data->restore_state);
+ led_set_brightness(led_cdev, transient_data->restore_state);
return size;
}

@@ -80,7 +80,7 @@ static ssize_t transient_activate_store(struct device *dev,
if (state == 1 && transient_data->activate == 0 &&
transient_data->duration != 0) {
transient_data->activate = state;
- __led_set_brightness(led_cdev, transient_data->state);
+ led_set_brightness(led_cdev, transient_data->state);
transient_data->restore_state =
(transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
mod_timer(&transient_data->timer,
@@ -203,7 +203,7 @@ static void transient_trig_deactivate(struct led_classdev *led_cdev)

if (led_cdev->activated) {
del_timer_sync(&transient_data->timer);
- __led_set_brightness(led_cdev, transient_data->restore_state);
+ led_set_brightness(led_cdev, transient_data->restore_state);
device_remove_file(led_cdev->dev, &dev_attr_activate);
device_remove_file(led_cdev->dev, &dev_attr_duration);
device_remove_file(led_cdev->dev, &dev_attr_state);
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 5676197..d7f5697 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -43,10 +43,15 @@ struct led_classdev {
#define LED_BLINK_ONESHOT_STOP (1 << 18)
#define LED_BLINK_INVERT (1 << 19)

- /* Set LED brightness level */
- /* Must not sleep, use a workqueue if needed */
+ /*
+ * Set LED brightness level
+ * use a workqueue internally, so driver writer doesn't need to
+ * care about using duplicated workqueue in brightness_set()
+ */
void (*brightness_set)(struct led_classdev *led_cdev,
enum led_brightness brightness);
+ struct work_struct set_brightness_work;
+
/* Get LED brightness level */
enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);

@@ -70,9 +75,6 @@ struct led_classdev {
struct timer_list blink_timer;
int blink_brightness;

- struct work_struct set_brightness_work;
- int delayed_set_value;
-
#ifdef CONFIG_LEDS_TRIGGERS
/* Protects the trigger data below */
struct rw_semaphore trigger_lock;
--
1.7.11.4

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