202 lines
5.0 KiB
C
202 lines
5.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ledtrig-gio.c - LED Trigger Based on GPIO events
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*
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* Copyright 2009 Felipe Balbi <me@felipebalbi.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/gpio.h>
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#include <linux/interrupt.h>
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#include <linux/leds.h>
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#include <linux/slab.h>
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#include "../leds.h"
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struct gpio_trig_data {
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struct led_classdev *led;
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unsigned desired_brightness; /* desired brightness when led is on */
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unsigned inverted; /* true when gpio is inverted */
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unsigned gpio; /* gpio that triggers the leds */
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};
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static irqreturn_t gpio_trig_irq(int irq, void *_led)
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{
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struct led_classdev *led = _led;
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struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
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int tmp;
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tmp = gpio_get_value_cansleep(gpio_data->gpio);
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if (gpio_data->inverted)
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tmp = !tmp;
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if (tmp) {
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if (gpio_data->desired_brightness)
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led_set_brightness_nosleep(gpio_data->led,
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gpio_data->desired_brightness);
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else
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led_set_brightness_nosleep(gpio_data->led, LED_FULL);
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} else {
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led_set_brightness_nosleep(gpio_data->led, LED_OFF);
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}
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return IRQ_HANDLED;
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}
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static ssize_t gpio_trig_brightness_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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return sprintf(buf, "%u\n", gpio_data->desired_brightness);
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}
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static ssize_t gpio_trig_brightness_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t n)
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{
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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unsigned desired_brightness;
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int ret;
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ret = sscanf(buf, "%u", &desired_brightness);
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if (ret < 1 || desired_brightness > 255) {
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dev_err(dev, "invalid value\n");
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return -EINVAL;
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}
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gpio_data->desired_brightness = desired_brightness;
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return n;
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}
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static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
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gpio_trig_brightness_store);
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static ssize_t gpio_trig_inverted_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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return sprintf(buf, "%u\n", gpio_data->inverted);
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}
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static ssize_t gpio_trig_inverted_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t n)
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{
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struct led_classdev *led = led_trigger_get_led(dev);
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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unsigned long inverted;
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int ret;
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ret = kstrtoul(buf, 10, &inverted);
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if (ret < 0)
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return ret;
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if (inverted > 1)
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return -EINVAL;
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gpio_data->inverted = inverted;
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/* After inverting, we need to update the LED. */
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gpio_trig_irq(0, led);
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return n;
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}
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static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
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gpio_trig_inverted_store);
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static ssize_t gpio_trig_gpio_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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return sprintf(buf, "%u\n", gpio_data->gpio);
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}
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static ssize_t gpio_trig_gpio_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t n)
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{
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struct led_classdev *led = led_trigger_get_led(dev);
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struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
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unsigned gpio;
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int ret;
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ret = sscanf(buf, "%u", &gpio);
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if (ret < 1) {
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dev_err(dev, "couldn't read gpio number\n");
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return -EINVAL;
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}
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if (gpio_data->gpio == gpio)
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return n;
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if (!gpio_is_valid(gpio)) {
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if (gpio_is_valid(gpio_data->gpio))
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free_irq(gpio_to_irq(gpio_data->gpio), led);
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gpio_data->gpio = gpio;
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return n;
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}
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ret = request_threaded_irq(gpio_to_irq(gpio), NULL, gpio_trig_irq,
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IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING
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| IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
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if (ret) {
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dev_err(dev, "request_irq failed with error %d\n", ret);
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} else {
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if (gpio_is_valid(gpio_data->gpio))
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free_irq(gpio_to_irq(gpio_data->gpio), led);
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gpio_data->gpio = gpio;
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/* After changing the GPIO, we need to update the LED. */
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gpio_trig_irq(0, led);
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}
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return ret ? ret : n;
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}
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static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
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static struct attribute *gpio_trig_attrs[] = {
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&dev_attr_desired_brightness.attr,
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&dev_attr_inverted.attr,
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&dev_attr_gpio.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(gpio_trig);
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static int gpio_trig_activate(struct led_classdev *led)
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{
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struct gpio_trig_data *gpio_data;
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gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
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if (!gpio_data)
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return -ENOMEM;
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gpio_data->led = led;
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gpio_data->gpio = -ENOENT;
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led_set_trigger_data(led, gpio_data);
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return 0;
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}
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static void gpio_trig_deactivate(struct led_classdev *led)
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{
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struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
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if (gpio_is_valid(gpio_data->gpio))
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free_irq(gpio_to_irq(gpio_data->gpio), led);
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kfree(gpio_data);
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}
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static struct led_trigger gpio_led_trigger = {
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.name = "gpio",
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.activate = gpio_trig_activate,
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.deactivate = gpio_trig_deactivate,
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.groups = gpio_trig_groups,
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};
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module_led_trigger(gpio_led_trigger);
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MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
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MODULE_DESCRIPTION("GPIO LED trigger");
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MODULE_LICENSE("GPL v2");
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