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Release 4.7 drivers/leds/trigger/ledtrig-gpio.c

/*
 * ledtrig-gio.c - LED Trigger Based on GPIO events
 *
 * Copyright 2009 Felipe Balbi <me@felipebalbi.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/leds.h>
#include <linux/slab.h>
#include "../leds.h"


struct gpio_trig_data {
	
struct led_classdev *led;
	
struct work_struct work;

	
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->trigger_data; /* just schedule_work since gpio_get_value can sleep */ schedule_work(&gpio_data->work); return IRQ_HANDLED; }

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;
static void gpio_trig_work(struct work_struct *work) { struct gpio_trig_data *gpio_data = container_of(work, struct gpio_trig_data, work); int tmp; if (!gpio_data->gpio) return; 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); } }

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static ssize_t gpio_trig_brightness_show(struct device *dev, struct device_attribute *attr, char *buf) { struct led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; return sprintf(buf, "%u\n", gpio_data->desired_brightness); }

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static ssize_t gpio_trig_brightness_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { struct led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; 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; }

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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 led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; return sprintf(buf, "%u\n", gpio_data->inverted); }

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static ssize_t gpio_trig_inverted_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { struct led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; 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. */ schedule_work(&gpio_data->work); return n; }

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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 led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; return sprintf(buf, "%u\n", gpio_data->gpio); }

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static ssize_t gpio_trig_gpio_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { struct led_classdev *led = dev_get_drvdata(dev); struct gpio_trig_data *gpio_data = led->trigger_data; unsigned gpio; int ret; ret = sscanf(buf, "%u", &gpio); if (ret < 1) { dev_err(dev, "couldn't read gpio number\n"); flush_work(&gpio_data->work); return -EINVAL; } if (gpio_data->gpio == gpio) return n; if (!gpio) { if (gpio_data->gpio != 0) free_irq(gpio_to_irq(gpio_data->gpio), led); gpio_data->gpio = 0; return n; } ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq, 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_data->gpio != 0) free_irq(gpio_to_irq(gpio_data->gpio), led); gpio_data->gpio = gpio; } return ret ? ret : n; }

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static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
static void gpio_trig_activate(struct led_classdev *led) { struct gpio_trig_data *gpio_data; int ret; gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL); if (!gpio_data) return; ret = device_create_file(led->dev, &dev_attr_gpio); if (ret) goto err_gpio; ret = device_create_file(led->dev, &dev_attr_inverted); if (ret) goto err_inverted; ret = device_create_file(led->dev, &dev_attr_desired_brightness); if (ret) goto err_brightness; gpio_data->led = led; led->trigger_data = gpio_data; INIT_WORK(&gpio_data->work, gpio_trig_work); led->activated = true; return; err_brightness: device_remove_file(led->dev, &dev_attr_inverted); err_inverted: device_remove_file(led->dev, &dev_attr_gpio); err_gpio: kfree(gpio_data); }

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static void gpio_trig_deactivate(struct led_classdev *led) { struct gpio_trig_data *gpio_data = led->trigger_data; if (led->activated) { device_remove_file(led->dev, &dev_attr_gpio); device_remove_file(led->dev, &dev_attr_inverted); device_remove_file(led->dev, &dev_attr_desired_brightness); flush_work(&gpio_data->work); if (gpio_data->gpio != 0) free_irq(gpio_to_irq(gpio_data->gpio), led); kfree(gpio_data); led->activated = false; } }

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static struct led_trigger gpio_led_trigger = { .name = "gpio", .activate = gpio_trig_activate, .deactivate = gpio_trig_deactivate, };
static int __init gpio_trig_init(void) { return led_trigger_register(&gpio_led_trigger); }

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module_init(gpio_trig_init);
static void __exit gpio_trig_exit(void) { led_trigger_unregister(&gpio_led_trigger); }

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module_exit(gpio_trig_exit); MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); MODULE_DESCRIPTION("GPIO LED trigger"); MODULE_LICENSE("GPL");

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