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");