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// SPDX-License-Identifier: GPL-2.0-only
/*
* ledtrig-gio.c - LED Trigger Based on GPIO events
*
* Copyright 2009 Felipe Balbi <me@felipebalbi.com>
* Copyright 2023 Linus Walleij <linus.walleij@linaro.org>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include "../leds.h"
struct gpio_trig_data {
struct led_classdev *led;
unsigned desired_brightness; /* desired brightness when led is on */
struct gpio_desc *gpiod; /* gpio that triggers the led */
};
static irqreturn_t gpio_trig_irq(int irq, void *_led)
{
struct led_classdev *led = _led;
struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
int tmp;
tmp = gpiod_get_value_cansleep(gpio_data->gpiod);
if (tmp) {
if (gpio_data->desired_brightness)
led_set_brightness_nosleep(gpio_data->led,
gpio_data->desired_brightness);
else
led_set_brightness_nosleep(gpio_data->led, LED_FULL);
} else {
led_set_brightness_nosleep(gpio_data->led, LED_OFF);
}
return IRQ_HANDLED;
}
static ssize_t gpio_trig_brightness_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
return sprintf(buf, "%u\n", gpio_data->desired_brightness);
}
static ssize_t gpio_trig_brightness_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned desired_brightness;
int ret;
ret = sscanf(buf, "%u", &desired_brightness);
if (ret < 1 || desired_brightness > 255) {
dev_err(dev, "invalid value\n");
return -EINVAL;
}
gpio_data->desired_brightness = desired_brightness;
return n;
}
static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
gpio_trig_brightness_store);
static struct attribute *gpio_trig_attrs[] = {
&dev_attr_desired_brightness.attr,
NULL
};
ATTRIBUTE_GROUPS(gpio_trig);
static int gpio_trig_activate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data;
struct device *dev = led->dev;
int ret;
gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
if (!gpio_data)
return -ENOMEM;
/*
* The generic property "trigger-sources" is followed,
* and we hope that this is a GPIO.
*/
gpio_data->gpiod = fwnode_gpiod_get_index(dev->fwnode,
"trigger-sources",
0, GPIOD_IN,
"led-trigger");
if (IS_ERR(gpio_data->gpiod)) {
ret = PTR_ERR(gpio_data->gpiod);
kfree(gpio_data);
return ret;
}
if (!gpio_data->gpiod) {
dev_err(dev, "no valid GPIO for the trigger\n");
kfree(gpio_data);
return -EINVAL;
}
gpio_data->led = led;
led_set_trigger_data(led, gpio_data);
ret = request_threaded_irq(gpiod_to_irq(gpio_data->gpiod), NULL, gpio_trig_irq,
IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING
| IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
if (ret) {
dev_err(dev, "request_irq failed with error %d\n", ret);
gpiod_put(gpio_data->gpiod);
kfree(gpio_data);
return ret;
}
/* Finally update the LED to initial status */
gpio_trig_irq(0, led);
return 0;
}
static void gpio_trig_deactivate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
free_irq(gpiod_to_irq(gpio_data->gpiod), led);
gpiod_put(gpio_data->gpiod);
kfree(gpio_data);
}
static struct led_trigger gpio_led_trigger = {
.name = "gpio",
.activate = gpio_trig_activate,
.deactivate = gpio_trig_deactivate,
.groups = gpio_trig_groups,
};
module_led_trigger(gpio_led_trigger);
MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
MODULE_DESCRIPTION("GPIO LED trigger");
MODULE_LICENSE("GPL v2");
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