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>
diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index 431dcb6..47d90db 100644
--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -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 @@
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 @@
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 @@
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 @@
gpio_free(leds_data[i].gpio);
}
}
+
+ flush_scheduled_work();
kfree(leds_data);
return ret;