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 000000000000..35812e3a37f2
--- /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(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");