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8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/init.h>
11#include <linux/gpio.h>
12#include <linux/interrupt.h>
13#include <linux/leds.h>
14#include <linux/slab.h>
15#include "../leds.h"
16
17struct gpio_trig_data {
18 struct led_classdev *led;
19
20 unsigned desired_brightness;
21 unsigned inverted;
22 unsigned gpio;
23};
24
25static irqreturn_t gpio_trig_irq(int irq, void *_led)
26{
27 struct led_classdev *led = _led;
28 struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
29 int tmp;
30
31 tmp = gpio_get_value_cansleep(gpio_data->gpio);
32 if (gpio_data->inverted)
33 tmp = !tmp;
34
35 if (tmp) {
36 if (gpio_data->desired_brightness)
37 led_set_brightness_nosleep(gpio_data->led,
38 gpio_data->desired_brightness);
39 else
40 led_set_brightness_nosleep(gpio_data->led, LED_FULL);
41 } else {
42 led_set_brightness_nosleep(gpio_data->led, LED_OFF);
43 }
44
45 return IRQ_HANDLED;
46}
47
48static ssize_t gpio_trig_brightness_show(struct device *dev,
49 struct device_attribute *attr, char *buf)
50{
51 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
52
53 return sprintf(buf, "%u\n", gpio_data->desired_brightness);
54}
55
56static ssize_t gpio_trig_brightness_store(struct device *dev,
57 struct device_attribute *attr, const char *buf, size_t n)
58{
59 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
60 unsigned desired_brightness;
61 int ret;
62
63 ret = sscanf(buf, "%u", &desired_brightness);
64 if (ret < 1 || desired_brightness > 255) {
65 dev_err(dev, "invalid value\n");
66 return -EINVAL;
67 }
68
69 gpio_data->desired_brightness = desired_brightness;
70
71 return n;
72}
73static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show,
74 gpio_trig_brightness_store);
75
76static ssize_t gpio_trig_inverted_show(struct device *dev,
77 struct device_attribute *attr, char *buf)
78{
79 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
80
81 return sprintf(buf, "%u\n", gpio_data->inverted);
82}
83
84static ssize_t gpio_trig_inverted_store(struct device *dev,
85 struct device_attribute *attr, const char *buf, size_t n)
86{
87 struct led_classdev *led = led_trigger_get_led(dev);
88 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
89 unsigned long inverted;
90 int ret;
91
92 ret = kstrtoul(buf, 10, &inverted);
93 if (ret < 0)
94 return ret;
95
96 if (inverted > 1)
97 return -EINVAL;
98
99 gpio_data->inverted = inverted;
100
101
102 if (gpio_is_valid(gpio_data->gpio))
103 gpio_trig_irq(0, led);
104
105 return n;
106}
107static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show,
108 gpio_trig_inverted_store);
109
110static ssize_t gpio_trig_gpio_show(struct device *dev,
111 struct device_attribute *attr, char *buf)
112{
113 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
114
115 return sprintf(buf, "%u\n", gpio_data->gpio);
116}
117
118static ssize_t gpio_trig_gpio_store(struct device *dev,
119 struct device_attribute *attr, const char *buf, size_t n)
120{
121 struct led_classdev *led = led_trigger_get_led(dev);
122 struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
123 unsigned gpio;
124 int ret;
125
126 ret = sscanf(buf, "%u", &gpio);
127 if (ret < 1) {
128 dev_err(dev, "couldn't read gpio number\n");
129 return -EINVAL;
130 }
131
132 if (gpio_data->gpio == gpio)
133 return n;
134
135 if (!gpio_is_valid(gpio)) {
136 if (gpio_is_valid(gpio_data->gpio))
137 free_irq(gpio_to_irq(gpio_data->gpio), led);
138 gpio_data->gpio = gpio;
139 return n;
140 }
141
142 ret = request_threaded_irq(gpio_to_irq(gpio), NULL, gpio_trig_irq,
143 IRQF_ONESHOT | IRQF_SHARED | IRQF_TRIGGER_RISING
144 | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led);
145 if (ret) {
146 dev_err(dev, "request_irq failed with error %d\n", ret);
147 } else {
148 if (gpio_is_valid(gpio_data->gpio))
149 free_irq(gpio_to_irq(gpio_data->gpio), led);
150 gpio_data->gpio = gpio;
151
152 gpio_trig_irq(0, led);
153 }
154
155 return ret ? ret : n;
156}
157static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
158
159static struct attribute *gpio_trig_attrs[] = {
160 &dev_attr_desired_brightness.attr,
161 &dev_attr_inverted.attr,
162 &dev_attr_gpio.attr,
163 NULL
164};
165ATTRIBUTE_GROUPS(gpio_trig);
166
167static int gpio_trig_activate(struct led_classdev *led)
168{
169 struct gpio_trig_data *gpio_data;
170
171 gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
172 if (!gpio_data)
173 return -ENOMEM;
174
175 gpio_data->led = led;
176 gpio_data->gpio = -ENOENT;
177
178 led_set_trigger_data(led, gpio_data);
179
180 return 0;
181}
182
183static void gpio_trig_deactivate(struct led_classdev *led)
184{
185 struct gpio_trig_data *gpio_data = led_get_trigger_data(led);
186
187 if (gpio_is_valid(gpio_data->gpio))
188 free_irq(gpio_to_irq(gpio_data->gpio), led);
189 kfree(gpio_data);
190}
191
192static struct led_trigger gpio_led_trigger = {
193 .name = "gpio",
194 .activate = gpio_trig_activate,
195 .deactivate = gpio_trig_deactivate,
196 .groups = gpio_trig_groups,
197};
198module_led_trigger(gpio_led_trigger);
199
200MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>");
201MODULE_DESCRIPTION("GPIO LED trigger");
202MODULE_LICENSE("GPL v2");
203
