leds: allow led-drivers to use a variable range of brightness values
This patch allows drivers to override the default maximum brightness value
of 255. We take care to preserve backwards-compatibility as much as
possible, so that user-space ABI doesn't change for existing drivers.
LED trigger code has also been updated to use the per-LED maximum.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 52f82e3..f2cc13d 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -64,7 +64,16 @@
return ret;
}
+static ssize_t led_max_brightness_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", led_cdev->max_brightness);
+}
+
static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store);
+static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL);
#ifdef CONFIG_LEDS_TRIGGERS
static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
#endif
@@ -138,6 +147,13 @@
list_add_tail(&led_cdev->node, &leds_list);
up_write(&leds_list_lock);
+ if (!led_cdev->max_brightness)
+ led_cdev->max_brightness = LED_FULL;
+
+ rc = device_create_file(led_cdev->dev, &dev_attr_max_brightness);
+ if (rc)
+ goto err_out_attr_max;
+
led_update_brightness(led_cdev);
#ifdef CONFIG_LEDS_TRIGGERS
@@ -155,9 +171,11 @@
#ifdef CONFIG_LEDS_TRIGGERS
err_out_led_list:
+ device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
+#endif
+err_out_attr_max:
device_remove_file(led_cdev->dev, &dev_attr_brightness);
list_del(&led_cdev->node);
-#endif
err_out:
device_unregister(led_cdev->dev);
return rc;
@@ -172,6 +190,7 @@
*/
void led_classdev_unregister(struct led_classdev *led_cdev)
{
+ device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
device_remove_file(led_cdev->dev, &dev_attr_brightness);
#ifdef CONFIG_LEDS_TRIGGERS
device_remove_file(led_cdev->dev, &dev_attr_trigger);
