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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: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
This commit is contained in:
David Brownell 2007-05-10 10:51:41 +01:00 committed by Richard Purdie
parent 22e03f3b58
commit 00852279af
1 changed files with 26 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/leds/leds-gpio.c
View File

@ -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)
@ -37,7 +49,15 @@ static void gpio_led_set(struct led_classdev *led_cdev,
if (led_dat->active_low)
level = !level;
gpio_set_value(led_dat->gpio, 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);
}
static int __init gpio_led_probe(struct platform_device *pdev)
@ -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 @@ err:
gpio_free(leds_data[i].gpio);
}
}
flush_scheduled_work();
kfree(leds_data);
return ret;