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-rw-r--r--Documentation/ABI/testing/sysfs-class-led9
-rw-r--r--drivers/leds/ledtrig-backlight.c61
2 files changed, 66 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 9e4541d71cb6..edff6630c805 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -26,3 +26,12 @@ Description:
scheduler is chosen. Trigger specific parameters can appear in
/sys/class/leds/<led> once a given trigger is selected.
+What: /sys/class/leds/<led>/inverted
+Date: January 2011
+KernelVersion: 2.6.38
+Contact: Richard Purdie <rpurdie@rpsys.net>
+Description:
+ Invert the LED on/off state. This parameter is specific to
+ gpio and backlight triggers. In case of the backlight trigger,
+ it is usefull when driving a LED which is intended to indicate
+ a device in a standby like state.
diff --git a/drivers/leds/ledtrig-backlight.c b/drivers/leds/ledtrig-backlight.c
index f948e57bd9b8..2b513a2ad7de 100644
--- a/drivers/leds/ledtrig-backlight.c
+++ b/drivers/leds/ledtrig-backlight.c
@@ -26,6 +26,7 @@ struct bl_trig_notifier {
int brightness;
int old_status;
struct notifier_block notifier;
+ unsigned invert;
};
static int fb_notifier_callback(struct notifier_block *p,
@@ -36,23 +37,64 @@ static int fb_notifier_callback(struct notifier_block *p,
struct led_classdev *led = n->led;
struct fb_event *fb_event = data;
int *blank = fb_event->data;
+ int new_status = *blank ? BLANK : UNBLANK;
switch (event) {
case FB_EVENT_BLANK :
- if (*blank && n->old_status == UNBLANK) {
+ if (new_status == n->old_status)
+ break;
+
+ if ((n->old_status == UNBLANK) ^ n->invert) {
n->brightness = led->brightness;
led_set_brightness(led, LED_OFF);
- n->old_status = BLANK;
- } else if (!*blank && n->old_status == BLANK) {
+ } else {
led_set_brightness(led, n->brightness);
- n->old_status = UNBLANK;
}
+
+ n->old_status = new_status;
+
break;
}
return 0;
}
+static ssize_t bl_trig_invert_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led = dev_get_drvdata(dev);
+ struct bl_trig_notifier *n = led->trigger_data;
+
+ return sprintf(buf, "%u\n", n->invert);
+}
+
+static ssize_t bl_trig_invert_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t num)
+{
+ struct led_classdev *led = dev_get_drvdata(dev);
+ struct bl_trig_notifier *n = led->trigger_data;
+ unsigned long invert;
+ int ret;
+
+ ret = strict_strtoul(buf, 10, &invert);
+ if (ret < 0)
+ return ret;
+
+ if (invert > 1)
+ return -EINVAL;
+
+ n->invert = invert;
+
+ /* After inverting, we need to update the LED. */
+ if ((n->old_status == BLANK) ^ n->invert)
+ led_set_brightness(led, LED_OFF);
+ else
+ led_set_brightness(led, n->brightness);
+
+ return num;
+}
+static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store);
+
static void bl_trig_activate(struct led_classdev *led)
{
int ret;
@@ -66,6 +108,10 @@ static void bl_trig_activate(struct led_classdev *led)
return;
}
+ ret = device_create_file(led->dev, &dev_attr_inverted);
+ if (ret)
+ goto err_invert;
+
n->led = led;
n->brightness = led->brightness;
n->old_status = UNBLANK;
@@ -74,6 +120,12 @@ static void bl_trig_activate(struct led_classdev *led)
ret = fb_register_client(&n->notifier);
if (ret)
dev_err(led->dev, "unable to register backlight trigger\n");
+
+ return;
+
+err_invert:
+ led->trigger_data = NULL;
+ kfree(n);
}
static void bl_trig_deactivate(struct led_classdev *led)
@@ -82,6 +134,7 @@ static void bl_trig_deactivate(struct led_classdev *led)
(struct bl_trig_notifier *) led->trigger_data;
if (n) {
+ device_remove_file(led->dev, &dev_attr_inverted);
fb_unregister_client(&n->notifier);
kfree(n);
}