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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ledtrig-gio.c - LED Trigger Based on GPIO events
4 *
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 else
36 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 NULL
72};
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_RISING
108 | 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");
1/*
2 * ledtrig-gio.c - LED Trigger Based on GPIO events
3 *
4 * Copyright 2009 Felipe Balbi <me@felipebalbi.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/gpio.h>
16#include <linux/interrupt.h>
17#include <linux/workqueue.h>
18#include <linux/leds.h>
19#include <linux/slab.h>
20#include "../leds.h"
21
22struct gpio_trig_data {
23 struct led_classdev *led;
24 struct work_struct work;
25
26 unsigned desired_brightness; /* desired brightness when led is on */
27 unsigned inverted; /* true when gpio is inverted */
28 unsigned gpio; /* gpio that triggers the leds */
29};
30
31static irqreturn_t gpio_trig_irq(int irq, void *_led)
32{
33 struct led_classdev *led = _led;
34 struct gpio_trig_data *gpio_data = led->trigger_data;
35
36 /* just schedule_work since gpio_get_value can sleep */
37 schedule_work(&gpio_data->work);
38
39 return IRQ_HANDLED;
40};
41
42static void gpio_trig_work(struct work_struct *work)
43{
44 struct gpio_trig_data *gpio_data = container_of(work,
45 struct gpio_trig_data, work);
46 int tmp;
47
48 if (!gpio_data->gpio)
49 return;
50
51 tmp = gpio_get_value_cansleep(gpio_data->gpio);
52 if (gpio_data->inverted)
53 tmp = !tmp;
54
55 if (tmp) {
56 if (gpio_data->desired_brightness)
57 led_set_brightness_nosleep(gpio_data->led,
58 gpio_data->desired_brightness);
59 else
60 led_set_brightness_nosleep(gpio_data->led, LED_FULL);
61 } else {
62 led_set_brightness_nosleep(gpio_data->led, LED_OFF);
63 }
64}
65
66static ssize_t gpio_trig_brightness_show(struct device *dev,
67 struct device_attribute *attr, char *buf)
68{
69 struct led_classdev *led = dev_get_drvdata(dev);
70 struct gpio_trig_data *gpio_data = led->trigger_data;
71
72 return sprintf(buf, "%u\n", gpio_data->desired_brightness);
73}
74
75static ssize_t gpio_trig_brightness_store(struct device *dev,
76 struct device_attribute *attr, const char *buf, size_t n)
77{
78 struct led_classdev *led = dev_get_drvdata(dev);
79 struct gpio_trig_data *gpio_data = led->trigger_data;
80 unsigned desired_brightness;
81 int ret;
82
83 ret = sscanf(buf, "%u", &desired_brightness);
84 if (ret < 1 || desired_brightness > 255) {
85 dev_err(dev, "invalid value\n");
86 return -EINVAL;
87 }
88
89 gpio_data->desired_brightness = desired_brightness;
90
91 return n;
92}
93static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
94 gpio_trig_brightness_store);
95
96static ssize_t gpio_trig_inverted_show(struct device *dev,
97 struct device_attribute *attr, char *buf)
98{
99 struct led_classdev *led = dev_get_drvdata(dev);
100 struct gpio_trig_data *gpio_data = led->trigger_data;
101
102 return sprintf(buf, "%u\n", gpio_data->inverted);
103}
104
105static ssize_t gpio_trig_inverted_store(struct device *dev,
106 struct device_attribute *attr, const char *buf, size_t n)
107{
108 struct led_classdev *led = dev_get_drvdata(dev);
109 struct gpio_trig_data *gpio_data = led->trigger_data;
110 unsigned long inverted;
111 int ret;
112
113 ret = kstrtoul(buf, 10, &inverted);
114 if (ret < 0)
115 return ret;
116
117 if (inverted > 1)
118 return -EINVAL;
119
120 gpio_data->inverted = inverted;
121
122 /* After inverting, we need to update the LED. */
123 schedule_work(&gpio_data->work);
124
125 return n;
126}
127static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
128 gpio_trig_inverted_store);
129
130static ssize_t gpio_trig_gpio_show(struct device *dev,
131 struct device_attribute *attr, char *buf)
132{
133 struct led_classdev *led = dev_get_drvdata(dev);
134 struct gpio_trig_data *gpio_data = led->trigger_data;
135
136 return sprintf(buf, "%u\n", gpio_data->gpio);
137}
138
139static ssize_t gpio_trig_gpio_store(struct device *dev,
140 struct device_attribute *attr, const char *buf, size_t n)
141{
142 struct led_classdev *led = dev_get_drvdata(dev);
143 struct gpio_trig_data *gpio_data = led->trigger_data;
144 unsigned gpio;
145 int ret;
146
147 ret = sscanf(buf, "%u", &gpio);
148 if (ret < 1) {
149 dev_err(dev, "couldn't read gpio number\n");
150 flush_work(&gpio_data->work);
151 return -EINVAL;
152 }
153
154 if (gpio_data->gpio == gpio)
155 return n;
156
157 if (!gpio) {
158 if (gpio_data->gpio != 0)
159 free_irq(gpio_to_irq(gpio_data->gpio), led);
160 gpio_data->gpio = 0;
161 return n;
162 }
163
164 ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq,
165 IRQF_SHARED | IRQF_TRIGGER_RISING
166 | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
167 if (ret) {
168 dev_err(dev, "request_irq failed with error %d\n", ret);
169 } else {
170 if (gpio_data->gpio != 0)
171 free_irq(gpio_to_irq(gpio_data->gpio), led);
172 gpio_data->gpio = gpio;
173 }
174
175 return ret ? ret : n;
176}
177static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
178
179static void gpio_trig_activate(struct led_classdev *led)
180{
181 struct gpio_trig_data *gpio_data;
182 int ret;
183
184 gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
185 if (!gpio_data)
186 return;
187
188 ret = device_create_file(led->dev, &dev_attr_gpio);
189 if (ret)
190 goto err_gpio;
191
192 ret = device_create_file(led->dev, &dev_attr_inverted);
193 if (ret)
194 goto err_inverted;
195
196 ret = device_create_file(led->dev, &dev_attr_desired_brightness);
197 if (ret)
198 goto err_brightness;
199
200 gpio_data->led = led;
201 led->trigger_data = gpio_data;
202 INIT_WORK(&gpio_data->work, gpio_trig_work);
203 led->activated = true;
204
205 return;
206
207err_brightness:
208 device_remove_file(led->dev, &dev_attr_inverted);
209
210err_inverted:
211 device_remove_file(led->dev, &dev_attr_gpio);
212
213err_gpio:
214 kfree(gpio_data);
215}
216
217static void gpio_trig_deactivate(struct led_classdev *led)
218{
219 struct gpio_trig_data *gpio_data = led->trigger_data;
220
221 if (led->activated) {
222 device_remove_file(led->dev, &dev_attr_gpio);
223 device_remove_file(led->dev, &dev_attr_inverted);
224 device_remove_file(led->dev, &dev_attr_desired_brightness);
225 flush_work(&gpio_data->work);
226 if (gpio_data->gpio != 0)
227 free_irq(gpio_to_irq(gpio_data->gpio), led);
228 kfree(gpio_data);
229 led->activated = false;
230 }
231}
232
233static struct led_trigger gpio_led_trigger = {
234 .name = "gpio",
235 .activate = gpio_trig_activate,
236 .deactivate = gpio_trig_deactivate,
237};
238
239static int __init gpio_trig_init(void)
240{
241 return led_trigger_register(&gpio_led_trigger);
242}
243module_init(gpio_trig_init);
244
245static void __exit gpio_trig_exit(void)
246{
247 led_trigger_unregister(&gpio_led_trigger);
248}
249module_exit(gpio_trig_exit);
250
251MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
252MODULE_DESCRIPTION("GPIO LED trigger");
253MODULE_LICENSE("GPL");