diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-led | 9 | ||||
| -rw-r--r-- | drivers/leds/ledtrig-backlight.c | 61 |
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); } |