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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>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio.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 */
unsigned inverted; /* true when gpio is inverted */
unsigned gpio; /* gpio that triggers the leds */
};
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 = gpio_get_value_cansleep(gpio_data->gpio);
if (gpio_data->inverted)
tmp = !tmp;
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 ssize_t gpio_trig_inverted_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->inverted);
}
static ssize_t gpio_trig_inverted_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct led_classdev *led = led_trigger_get_led(dev);
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned long inverted;
int ret;
ret = kstrtoul(buf, 10, &inverted);
if (ret < 0)
return ret;
if (inverted > 1)
return -EINVAL;
gpio_data->inverted = inverted;
/* After inverting, we need to update the LED. */
gpio_trig_irq(0, led);
return n;
}
static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
gpio_trig_inverted_store);
static ssize_t gpio_trig_gpio_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->gpio);
}
static ssize_t gpio_trig_gpio_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t n)
{
struct led_classdev *led = led_trigger_get_led(dev);
struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
unsigned gpio;
int ret;
ret = sscanf(buf, "%u", &gpio);
if (ret < 1) {
dev_err(dev, "couldn't read gpio number\n");
return -EINVAL;
}
if (gpio_data->gpio == gpio)
return n;
if (!gpio_is_valid(gpio)) {
if (gpio_is_valid(gpio_data->gpio))
free_irq(gpio_to_irq(gpio_data->gpio), led);
gpio_data->gpio = gpio;
return n;
}
ret = request_threaded_irq(gpio_to_irq(gpio), 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);
} else {
if (gpio_is_valid(gpio_data->gpio))
free_irq(gpio_to_irq(gpio_data->gpio), led);
gpio_data->gpio = gpio;
/* After changing the GPIO, we need to update the LED. */
gpio_trig_irq(0, led);
}
return ret ? ret : n;
}
static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
static struct attribute *gpio_trig_attrs[] = {
&dev_attr_desired_brightness.attr,
&dev_attr_inverted.attr,
&dev_attr_gpio.attr,
NULL
};
ATTRIBUTE_GROUPS(gpio_trig);
static int gpio_trig_activate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data;
gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
if (!gpio_data)
return -ENOMEM;
gpio_data->led = led;
gpio_data->gpio = -ENOENT;
led_set_trigger_data(led, gpio_data);
return 0;
}
static void gpio_trig_deactivate(struct led_classdev *led)
{
struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
if (gpio_is_valid(gpio_data->gpio))
free_irq(gpio_to_irq(gpio_data->gpio), led);
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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