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Commit 00852279 authored by David Brownell's avatar David Brownell Committed by Richard Purdie
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leds: Teach leds-gpio to handle timer-unsafe GPIOs 



Teach the new leds-gpio driver that some GPIOs can't be accessed from
timer callbacks ... which is how all today's standard triggers use them.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarRichard Purdie <rpurdie@rpsys.net>
parent 22e03f3b

drivers/leds/leds-gpio.c

+26 −1
Original line number Diff line number Diff line
@@ -13,14 +13,26 @@ 
#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/leds.h>

#include <linux/workqueue.h>



#include <asm/gpio.h>



struct gpio_led_data {

	struct led_classdev cdev;

	unsigned gpio;

	struct work_struct work;

	u8 new_level;

	u8 can_sleep;

	u8 active_low;

};



static void gpio_led_work(struct work_struct *work)

{

	struct gpio_led_data	*led_dat =

		container_of(work, struct gpio_led_data, work);



	gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);

}



static void gpio_led_set(struct led_classdev *led_cdev,

	enum led_brightness value)
@@ -37,6 +49,14 @@ static void gpio_led_set(struct led_classdev *led_cdev, 
	if (led_dat->active_low)

		level = !level;



	/* setting GPIOs with I2C/etc requires a preemptible task context */

	if (led_dat->can_sleep) {

		if (preempt_count()) {

			led_dat->new_level = level;

			schedule_work(&led_dat->work);

		} else

			gpio_set_value_cansleep(led_dat->gpio, level);

	} else

		gpio_set_value(led_dat->gpio, level);

}
@@ -62,6 +82,7 @@ static int __init gpio_led_probe(struct platform_device *pdev) 
		led_dat->cdev.name = cur_led->name;

		led_dat->cdev.default_trigger = cur_led->default_trigger;

		led_dat->gpio = cur_led->gpio;

		led_dat->can_sleep = gpio_cansleep(cur_led->gpio);

		led_dat->active_low = cur_led->active_low;

		led_dat->cdev.brightness_set = gpio_led_set;

		led_dat->cdev.brightness = cur_led->active_low ? LED_FULL : LED_OFF;
@@ -77,6 +98,8 @@ static int __init gpio_led_probe(struct platform_device *pdev) 
			gpio_free(led_dat->gpio);

			goto err;

		}



		INIT_WORK(&led_dat->work, gpio_led_work);

	}



	platform_set_drvdata(pdev, leds_data);
@@ -90,6 +113,8 @@ static int __init gpio_led_probe(struct platform_device *pdev) 
			gpio_free(leds_data[i].gpio);

		}

	}



	flush_scheduled_work();

	kfree(leds_data);



	return ret;