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202 lines
5.0 KiB
202 lines
5.0 KiB
// 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 <[email protected]> |
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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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if (gpio_is_valid(gpio_data->gpio)) |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("GPIO LED trigger"); |
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MODULE_LICENSE("GPL v2");
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