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authorGuennadi Liakhovetski <lg@denx.de>2009-01-10 21:54:39 +0300
committerRichard Purdie <rpurdie@linux.intel.com>2009-04-06 19:06:25 +0400
commit1bd465e6b0e2b559db47420fea686507a01cfab0 (patch)
tree623c7a906e4ce117873a33f5b1717e150d5f9e59 /drivers/leds/led-class.c
parenta7d878af94b223013a48078e0c8c0a654c24a057 (diff)
downloadlinux-1bd465e6b0e2b559db47420fea686507a01cfab0.tar.xz
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>
Diffstat (limited to 'drivers/leds/led-class.c')
-rw-r--r--drivers/leds/led-class.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 52f82e3ea13a..f2cc13d76810 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -64,7 +64,16 @@ static ssize_t led_brightness_store(struct device *dev,
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 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
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 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
#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 @@ EXPORT_SYMBOL_GPL(led_classdev_register);
*/
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);