diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-gpio.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-gpio.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c new file mode 100644 index 000000000..4cc704074 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-gpio.c @@ -0,0 +1,253 @@ +/* + * 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_async(gpio_data->led, + gpio_data->desired_brightness); + else + led_set_brightness_async(gpio_data->led, LED_FULL); + } else { + led_set_brightness_async(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"); |