Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 19 | #include <linux/slab.h> |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 20 | #include "leds.h" |
| 21 | |
| 22 | struct 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 | |
| 31 | static 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 | |
| 42 | static 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 | |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 48 | if (!gpio_data->gpio) |
| 49 | return; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 50 | |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 51 | tmp = gpio_get_value(gpio_data->gpio); |
| 52 | if (gpio_data->inverted) |
| 53 | tmp = !tmp; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 54 | |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 55 | if (tmp) { |
| 56 | if (gpio_data->desired_brightness) |
Shuah Khan | 0da3e65 | 2012-06-13 10:01:37 +0800 | [diff] [blame] | 57 | __led_set_brightness(gpio_data->led, |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 58 | gpio_data->desired_brightness); |
| 59 | else |
Shuah Khan | 0da3e65 | 2012-06-13 10:01:37 +0800 | [diff] [blame] | 60 | __led_set_brightness(gpio_data->led, LED_FULL); |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 61 | } else { |
Shuah Khan | 0da3e65 | 2012-06-13 10:01:37 +0800 | [diff] [blame] | 62 | __led_set_brightness(gpio_data->led, LED_OFF); |
Thadeu Lima de Souza Cascardo | 74cbe20 | 2009-08-06 16:04:51 -0700 | [diff] [blame] | 63 | } |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 64 | } |
| 65 | |
| 66 | static 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 | |
| 75 | static 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 | } |
| 93 | static DEVICE_ATTR(desired_brightness, 0644, gpio_trig_brightness_show, |
| 94 | gpio_trig_brightness_store); |
| 95 | |
| 96 | static 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 | |
Janusz Krzysztofik | cc587ec | 2011-01-20 14:44:29 -0800 | [diff] [blame] | 102 | return sprintf(buf, "%u\n", gpio_data->inverted); |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 103 | } |
| 104 | |
| 105 | static 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; |
Janusz Krzysztofik | cc587ec | 2011-01-20 14:44:29 -0800 | [diff] [blame] | 110 | unsigned long inverted; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 111 | int ret; |
| 112 | |
Jingoo Han | e894192 | 2012-10-23 05:27:52 -0700 | [diff] [blame^] | 113 | ret = kstrtoul(buf, 10, &inverted); |
Janusz Krzysztofik | cc587ec | 2011-01-20 14:44:29 -0800 | [diff] [blame] | 114 | if (ret < 0) |
| 115 | return ret; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 116 | |
Janusz Krzysztofik | cc587ec | 2011-01-20 14:44:29 -0800 | [diff] [blame] | 117 | if (inverted > 1) |
| 118 | return -EINVAL; |
| 119 | |
| 120 | gpio_data->inverted = inverted; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 121 | |
Thadeu Lima de Souza Cascardo | cc674c8 | 2009-08-26 14:29:32 -0700 | [diff] [blame] | 122 | /* After inverting, we need to update the LED. */ |
| 123 | schedule_work(&gpio_data->work); |
| 124 | |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 125 | return n; |
| 126 | } |
| 127 | static DEVICE_ATTR(inverted, 0644, gpio_trig_inverted_show, |
| 128 | gpio_trig_inverted_store); |
| 129 | |
| 130 | static 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 | |
| 139 | static 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 | |
Thadeu Lima de Souza Cascardo | 48cccd2 | 2009-08-26 14:29:31 -0700 | [diff] [blame] | 154 | if (gpio_data->gpio == gpio) |
| 155 | return n; |
| 156 | |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 157 | if (!gpio) { |
Thadeu Lima de Souza Cascardo | 48cccd2 | 2009-08-26 14:29:31 -0700 | [diff] [blame] | 158 | if (gpio_data->gpio != 0) |
| 159 | free_irq(gpio_to_irq(gpio_data->gpio), led); |
| 160 | gpio_data->gpio = 0; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 161 | return n; |
| 162 | } |
| 163 | |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 164 | ret = request_irq(gpio_to_irq(gpio), gpio_trig_irq, |
| 165 | IRQF_SHARED | IRQF_TRIGGER_RISING |
| 166 | | IRQF_TRIGGER_FALLING, "ledtrig-gpio", led); |
Thadeu Lima de Souza Cascardo | 48cccd2 | 2009-08-26 14:29:31 -0700 | [diff] [blame] | 167 | if (ret) { |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 168 | dev_err(dev, "request_irq failed with error %d\n", ret); |
Thadeu Lima de Souza Cascardo | 48cccd2 | 2009-08-26 14:29:31 -0700 | [diff] [blame] | 169 | } else { |
| 170 | if (gpio_data->gpio != 0) |
| 171 | free_irq(gpio_to_irq(gpio_data->gpio), led); |
| 172 | gpio_data->gpio = gpio; |
| 173 | } |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 174 | |
| 175 | return ret ? ret : n; |
| 176 | } |
| 177 | static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store); |
| 178 | |
| 179 | static 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); |
Shuah Khan | 03c091e | 2012-05-29 15:07:28 -0700 | [diff] [blame] | 203 | led->activated = true; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 204 | |
| 205 | return; |
| 206 | |
| 207 | err_brightness: |
| 208 | device_remove_file(led->dev, &dev_attr_inverted); |
| 209 | |
| 210 | err_inverted: |
| 211 | device_remove_file(led->dev, &dev_attr_gpio); |
| 212 | |
| 213 | err_gpio: |
| 214 | kfree(gpio_data); |
| 215 | } |
| 216 | |
| 217 | static void gpio_trig_deactivate(struct led_classdev *led) |
| 218 | { |
| 219 | struct gpio_trig_data *gpio_data = led->trigger_data; |
| 220 | |
Shuah Khan | 03c091e | 2012-05-29 15:07:28 -0700 | [diff] [blame] | 221 | if (led->activated) { |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 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); |
Thadeu Lima de Souza Cascardo | 48cccd2 | 2009-08-26 14:29:31 -0700 | [diff] [blame] | 226 | if (gpio_data->gpio != 0) |
| 227 | free_irq(gpio_to_irq(gpio_data->gpio), led); |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 228 | kfree(gpio_data); |
Shuah Khan | 03c091e | 2012-05-29 15:07:28 -0700 | [diff] [blame] | 229 | led->activated = false; |
Felipe Balbi | 17354bf | 2009-02-17 13:18:11 +0200 | [diff] [blame] | 230 | } |
| 231 | } |
| 232 | |
| 233 | static struct led_trigger gpio_led_trigger = { |
| 234 | .name = "gpio", |
| 235 | .activate = gpio_trig_activate, |
| 236 | .deactivate = gpio_trig_deactivate, |
| 237 | }; |
| 238 | |
| 239 | static int __init gpio_trig_init(void) |
| 240 | { |
| 241 | return led_trigger_register(&gpio_led_trigger); |
| 242 | } |
| 243 | module_init(gpio_trig_init); |
| 244 | |
| 245 | static void __exit gpio_trig_exit(void) |
| 246 | { |
| 247 | led_trigger_unregister(&gpio_led_trigger); |
| 248 | } |
| 249 | module_exit(gpio_trig_exit); |
| 250 | |
| 251 | MODULE_AUTHOR("Felipe Balbi <me@felipebalbi.com>"); |
| 252 | MODULE_DESCRIPTION("GPIO LED trigger"); |
| 253 | MODULE_LICENSE("GPL"); |