--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff