Orange Pi5 kernel

// 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");