143 lines
3.2 KiB
C
143 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Backlight emulation LED trigger
|
|
*
|
|
* Copyright 2008 (C) Rodolfo Giometti <giometti@linux.it>
|
|
* Copyright 2008 (C) Eurotech S.p.A. <info@eurotech.it>
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/init.h>
|
|
#include <linux/fb.h>
|
|
#include <linux/leds.h>
|
|
#include "../leds.h"
|
|
|
|
#define BLANK 1
|
|
#define UNBLANK 0
|
|
|
|
struct bl_trig_notifier {
|
|
struct led_classdev *led;
|
|
int brightness;
|
|
int old_status;
|
|
struct notifier_block notifier;
|
|
unsigned invert;
|
|
};
|
|
|
|
static int fb_notifier_callback(struct notifier_block *p,
|
|
unsigned long event, void *data)
|
|
{
|
|
struct bl_trig_notifier *n = container_of(p,
|
|
struct bl_trig_notifier, notifier);
|
|
struct led_classdev *led = n->led;
|
|
struct fb_event *fb_event = data;
|
|
int *blank;
|
|
int new_status;
|
|
|
|
/* If we aren't interested in this event, skip it immediately ... */
|
|
if (event != FB_EVENT_BLANK)
|
|
return 0;
|
|
|
|
blank = fb_event->data;
|
|
new_status = *blank ? BLANK : UNBLANK;
|
|
|
|
if (new_status == n->old_status)
|
|
return 0;
|
|
|
|
if ((n->old_status == UNBLANK) ^ n->invert) {
|
|
n->brightness = led->brightness;
|
|
led_set_brightness_nosleep(led, LED_OFF);
|
|
} else {
|
|
led_set_brightness_nosleep(led, n->brightness);
|
|
}
|
|
|
|
n->old_status = new_status;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t bl_trig_invert_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
struct bl_trig_notifier *n = led_trigger_get_drvdata(dev);
|
|
|
|
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 = led_trigger_get_led(dev);
|
|
struct bl_trig_notifier *n = led_trigger_get_drvdata(dev);
|
|
unsigned long invert;
|
|
int ret;
|
|
|
|
ret = kstrtoul(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_nosleep(led, LED_OFF);
|
|
else
|
|
led_set_brightness_nosleep(led, n->brightness);
|
|
|
|
return num;
|
|
}
|
|
static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store);
|
|
|
|
static struct attribute *bl_trig_attrs[] = {
|
|
&dev_attr_inverted.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(bl_trig);
|
|
|
|
static int bl_trig_activate(struct led_classdev *led)
|
|
{
|
|
int ret;
|
|
|
|
struct bl_trig_notifier *n;
|
|
|
|
n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
|
|
if (!n)
|
|
return -ENOMEM;
|
|
led_set_trigger_data(led, n);
|
|
|
|
n->led = led;
|
|
n->brightness = led->brightness;
|
|
n->old_status = UNBLANK;
|
|
n->notifier.notifier_call = fb_notifier_callback;
|
|
|
|
ret = fb_register_client(&n->notifier);
|
|
if (ret)
|
|
dev_err(led->dev, "unable to register backlight trigger\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void bl_trig_deactivate(struct led_classdev *led)
|
|
{
|
|
struct bl_trig_notifier *n = led_get_trigger_data(led);
|
|
|
|
fb_unregister_client(&n->notifier);
|
|
kfree(n);
|
|
}
|
|
|
|
static struct led_trigger bl_led_trigger = {
|
|
.name = "backlight",
|
|
.activate = bl_trig_activate,
|
|
.deactivate = bl_trig_deactivate,
|
|
.groups = bl_trig_groups,
|
|
};
|
|
module_led_trigger(bl_led_trigger);
|
|
|
|
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
|
|
MODULE_DESCRIPTION("Backlight emulation LED trigger");
|
|
MODULE_LICENSE("GPL v2");
|