142 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ledtrig-gio.c - LED Trigger Based on GPIO events4 *5 * Copyright 2009 Felipe Balbi <me@felipebalbi.com>6 * Copyright 2023 Linus Walleij <linus.walleij@linaro.org>7 */8 9#include <linux/module.h>10#include <linux/kernel.h>11#include <linux/init.h>12#include <linux/gpio/consumer.h>13#include <linux/interrupt.h>14#include <linux/leds.h>15#include <linux/slab.h>16#include "../leds.h"17 18struct gpio_trig_data {19 struct led_classdev *led;20 unsigned desired_brightness; /* desired brightness when led is on */21 struct gpio_desc *gpiod; /* gpio that triggers the led */22};23 24static irqreturn_t gpio_trig_irq(int irq, void *_led)25{26 struct led_classdev *led = _led;27 struct gpio_trig_data *gpio_data = led_get_trigger_data(led);28 int tmp;29 30 tmp = gpiod_get_value_cansleep(gpio_data->gpiod);31 if (tmp) {32 if (gpio_data->desired_brightness)33 led_set_brightness_nosleep(gpio_data->led,34 gpio_data->desired_brightness);35 else36 led_set_brightness_nosleep(gpio_data->led, LED_FULL);37 } else {38 led_set_brightness_nosleep(gpio_data->led, LED_OFF);39 }40 41 return IRQ_HANDLED;42}43 44static ssize_t desired_brightness_show(struct device *dev,45 struct device_attribute *attr, char *buf)46{47 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);48 49 return sysfs_emit(buf, "%u\n", gpio_data->desired_brightness);50}51 52static ssize_t desired_brightness_store(struct device *dev,53 struct device_attribute *attr, const char *buf, size_t n)54{55 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);56 u8 desired_brightness;57 int ret;58 59 ret = kstrtou8(buf, 10, &desired_brightness);60 if (ret)61 return ret;62 63 gpio_data->desired_brightness = desired_brightness;64 65 return n;66}67static DEVICE_ATTR_RW(desired_brightness);68 69static struct attribute *gpio_trig_attrs[] = {70 &dev_attr_desired_brightness.attr,71 NULL72};73ATTRIBUTE_GROUPS(gpio_trig);74 75static int gpio_trig_activate(struct led_classdev *led)76{77 struct gpio_trig_data *gpio_data;78 struct device *dev = led->dev;79 int ret;80 81 gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);82 if (!gpio_data)83 return -ENOMEM;84 85 /*86 * The generic property "trigger-sources" is followed,87 * and we hope that this is a GPIO.88 */89 gpio_data->gpiod = gpiod_get_optional(dev, "trigger-sources", GPIOD_IN);90 if (IS_ERR(gpio_data->gpiod)) {91 ret = PTR_ERR(gpio_data->gpiod);92 kfree(gpio_data);93 return ret;94 }95 if (!gpio_data->gpiod) {96 dev_err(dev, "no valid GPIO for the trigger\n");97 kfree(gpio_data);98 return -EINVAL;99 }100 101 gpiod_set_consumer_name(gpio_data->gpiod, "led-trigger");102 103 gpio_data->led = led;104 led_set_trigger_data(led, gpio_data);105 106 ret = request_threaded_irq(gpiod_to_irq(gpio_data->gpiod), NULL, gpio_trig_irq,107 IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING108 | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);109 if (ret) {110 dev_err(dev, "request_irq failed with error %d\n", ret);111 gpiod_put(gpio_data->gpiod);112 kfree(gpio_data);113 return ret;114 }115 116 /* Finally update the LED to initial status */117 gpio_trig_irq(0, led);118 119 return 0;120}121 122static void gpio_trig_deactivate(struct led_classdev *led)123{124 struct gpio_trig_data *gpio_data = led_get_trigger_data(led);125 126 free_irq(gpiod_to_irq(gpio_data->gpiod), led);127 gpiod_put(gpio_data->gpiod);128 kfree(gpio_data);129}130 131static struct led_trigger gpio_led_trigger = {132 .name = "gpio",133 .activate = gpio_trig_activate,134 .deactivate = gpio_trig_deactivate,135 .groups = gpio_trig_groups,136};137module_led_trigger(gpio_led_trigger);138 139MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");140MODULE_DESCRIPTION("GPIO LED trigger");141MODULE_LICENSE("GPL v2");142