1 /* 2 * LED Class Core 3 * 4 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu> 5 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/list.h> 16 #include <linux/spinlock.h> 17 #include <linux/device.h> 18 #include <linux/timer.h> 19 #include <linux/err.h> 20 #include <linux/ctype.h> 21 #include <linux/leds.h> 22 #include "leds.h" 23 24 static struct class *leds_class; 25 26 static void led_update_brightness(struct led_classdev *led_cdev) 27 { 28 if (led_cdev->brightness_get) 29 led_cdev->brightness = led_cdev->brightness_get(led_cdev); 30 } 31 32 static ssize_t brightness_show(struct device *dev, 33 struct device_attribute *attr, char *buf) 34 { 35 struct led_classdev *led_cdev = dev_get_drvdata(dev); 36 37 /* no lock needed for this */ 38 led_update_brightness(led_cdev); 39 40 return sprintf(buf, "%u\n", led_cdev->brightness); 41 } 42 43 static ssize_t brightness_store(struct device *dev, 44 struct device_attribute *attr, const char *buf, size_t size) 45 { 46 struct led_classdev *led_cdev = dev_get_drvdata(dev); 47 unsigned long state; 48 ssize_t ret = -EINVAL; 49 50 ret = kstrtoul(buf, 10, &state); 51 if (ret) 52 return ret; 53 54 if (state == LED_OFF) 55 led_trigger_remove(led_cdev); 56 __led_set_brightness(led_cdev, state); 57 58 return size; 59 } 60 static DEVICE_ATTR_RW(brightness); 61 62 static ssize_t led_max_brightness_show(struct device *dev, 63 struct device_attribute *attr, char *buf) 64 { 65 struct led_classdev *led_cdev = dev_get_drvdata(dev); 66 67 return sprintf(buf, "%u\n", led_cdev->max_brightness); 68 } 69 static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL); 70 71 #ifdef CONFIG_LEDS_TRIGGERS 72 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 73 static struct attribute *led_trigger_attrs[] = { 74 &dev_attr_trigger.attr, 75 NULL, 76 }; 77 static const struct attribute_group led_trigger_group = { 78 .attrs = led_trigger_attrs, 79 }; 80 #endif 81 82 static struct attribute *led_class_attrs[] = { 83 &dev_attr_brightness.attr, 84 &dev_attr_max_brightness.attr, 85 NULL, 86 }; 87 88 static const struct attribute_group led_group = { 89 .attrs = led_class_attrs, 90 }; 91 92 static const struct attribute_group *led_groups[] = { 93 &led_group, 94 #ifdef CONFIG_LEDS_TRIGGERS 95 &led_trigger_group, 96 #endif 97 NULL, 98 }; 99 100 static void led_timer_function(unsigned long data) 101 { 102 struct led_classdev *led_cdev = (void *)data; 103 unsigned long brightness; 104 unsigned long delay; 105 106 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 107 __led_set_brightness(led_cdev, LED_OFF); 108 return; 109 } 110 111 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 112 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 113 return; 114 } 115 116 brightness = led_get_brightness(led_cdev); 117 if (!brightness) { 118 /* Time to switch the LED on. */ 119 brightness = led_cdev->blink_brightness; 120 delay = led_cdev->blink_delay_on; 121 } else { 122 /* Store the current brightness value to be able 123 * to restore it when the delay_off period is over. 124 */ 125 led_cdev->blink_brightness = brightness; 126 brightness = LED_OFF; 127 delay = led_cdev->blink_delay_off; 128 } 129 130 __led_set_brightness(led_cdev, brightness); 131 132 /* Return in next iteration if led is in one-shot mode and we are in 133 * the final blink state so that the led is toggled each delay_on + 134 * delay_off milliseconds in worst case. 135 */ 136 if (led_cdev->flags & LED_BLINK_ONESHOT) { 137 if (led_cdev->flags & LED_BLINK_INVERT) { 138 if (brightness) 139 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 140 } else { 141 if (!brightness) 142 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 143 } 144 } 145 146 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 147 } 148 149 static void set_brightness_delayed(struct work_struct *ws) 150 { 151 struct led_classdev *led_cdev = 152 container_of(ws, struct led_classdev, set_brightness_work); 153 154 led_stop_software_blink(led_cdev); 155 156 __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 157 } 158 159 /** 160 * led_classdev_suspend - suspend an led_classdev. 161 * @led_cdev: the led_classdev to suspend. 162 */ 163 void led_classdev_suspend(struct led_classdev *led_cdev) 164 { 165 led_cdev->flags |= LED_SUSPENDED; 166 led_cdev->brightness_set(led_cdev, 0); 167 } 168 EXPORT_SYMBOL_GPL(led_classdev_suspend); 169 170 /** 171 * led_classdev_resume - resume an led_classdev. 172 * @led_cdev: the led_classdev to resume. 173 */ 174 void led_classdev_resume(struct led_classdev *led_cdev) 175 { 176 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 177 led_cdev->flags &= ~LED_SUSPENDED; 178 } 179 EXPORT_SYMBOL_GPL(led_classdev_resume); 180 181 static int led_suspend(struct device *dev) 182 { 183 struct led_classdev *led_cdev = dev_get_drvdata(dev); 184 185 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 186 led_classdev_suspend(led_cdev); 187 188 return 0; 189 } 190 191 static int led_resume(struct device *dev) 192 { 193 struct led_classdev *led_cdev = dev_get_drvdata(dev); 194 195 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 196 led_classdev_resume(led_cdev); 197 198 return 0; 199 } 200 201 static const struct dev_pm_ops leds_class_dev_pm_ops = { 202 .suspend = led_suspend, 203 .resume = led_resume, 204 }; 205 206 /** 207 * led_classdev_register - register a new object of led_classdev class. 208 * @parent: The device to register. 209 * @led_cdev: the led_classdev structure for this device. 210 */ 211 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 212 { 213 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 214 "%s", led_cdev->name); 215 if (IS_ERR(led_cdev->dev)) 216 return PTR_ERR(led_cdev->dev); 217 218 #ifdef CONFIG_LEDS_TRIGGERS 219 init_rwsem(&led_cdev->trigger_lock); 220 #endif 221 /* add to the list of leds */ 222 down_write(&leds_list_lock); 223 list_add_tail(&led_cdev->node, &leds_list); 224 up_write(&leds_list_lock); 225 226 if (!led_cdev->max_brightness) 227 led_cdev->max_brightness = LED_FULL; 228 229 led_update_brightness(led_cdev); 230 231 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 232 233 init_timer(&led_cdev->blink_timer); 234 led_cdev->blink_timer.function = led_timer_function; 235 led_cdev->blink_timer.data = (unsigned long)led_cdev; 236 237 #ifdef CONFIG_LEDS_TRIGGERS 238 led_trigger_set_default(led_cdev); 239 #endif 240 241 dev_dbg(parent, "Registered led device: %s\n", 242 led_cdev->name); 243 244 return 0; 245 } 246 EXPORT_SYMBOL_GPL(led_classdev_register); 247 248 /** 249 * led_classdev_unregister - unregisters a object of led_properties class. 250 * @led_cdev: the led device to unregister 251 * 252 * Unregisters a previously registered via led_classdev_register object. 253 */ 254 void led_classdev_unregister(struct led_classdev *led_cdev) 255 { 256 #ifdef CONFIG_LEDS_TRIGGERS 257 down_write(&led_cdev->trigger_lock); 258 if (led_cdev->trigger) 259 led_trigger_set(led_cdev, NULL); 260 up_write(&led_cdev->trigger_lock); 261 #endif 262 263 cancel_work_sync(&led_cdev->set_brightness_work); 264 265 /* Stop blinking */ 266 led_stop_software_blink(led_cdev); 267 led_set_brightness(led_cdev, LED_OFF); 268 269 device_unregister(led_cdev->dev); 270 271 down_write(&leds_list_lock); 272 list_del(&led_cdev->node); 273 up_write(&leds_list_lock); 274 } 275 EXPORT_SYMBOL_GPL(led_classdev_unregister); 276 277 static int __init leds_init(void) 278 { 279 leds_class = class_create(THIS_MODULE, "leds"); 280 if (IS_ERR(leds_class)) 281 return PTR_ERR(leds_class); 282 leds_class->pm = &leds_class_dev_pm_ops; 283 leds_class->dev_groups = led_groups; 284 return 0; 285 } 286 287 static void __exit leds_exit(void) 288 { 289 class_destroy(leds_class); 290 } 291 292 subsys_initcall(leds_init); 293 module_exit(leds_exit); 294 295 MODULE_AUTHOR("John Lenz, Richard Purdie"); 296 MODULE_LICENSE("GPL"); 297 MODULE_DESCRIPTION("LED Class Interface"); 298