| /* |
| * 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; |
| }; |
| |
| 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(gpio_data->led, |
| gpio_data->desired_brightness); |
| else |
| __led_set_brightness(gpio_data->led, LED_FULL); |
| } else { |
| __led_set_brightness(gpio_data->led, LED_OFF); |
| } |
| } |
| |
| 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); |
| } |
| |
| 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; |
| } |
| 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); |
| } |
| |
| 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; |
| } |
| 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); |
| } |
| |
| 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; |
| } |
| 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); |
| } |
| |
| 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; |
| } |
| } |
| |
| 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); |
| } |
| module_init(gpio_trig_init); |
| |
| static void __exit gpio_trig_exit(void) |
| { |
| led_trigger_unregister(&gpio_led_trigger); |
| } |
| module_exit(gpio_trig_exit); |
| |
| MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); |
| MODULE_DESCRIPTION("GPIO LED trigger"); |
| MODULE_LICENSE("GPL"); |