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/err.h> 19 #include <linux/ctype.h> 20 #include <linux/leds.h> 21 #include <linux/workqueue.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_work_function(struct work_struct *ws) 101 { 102 struct led_classdev *led_cdev = 103 container_of(ws, struct led_classdev, blink_work.work); 104 unsigned long brightness; 105 unsigned long delay; 106 107 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 108 __led_set_brightness(led_cdev, LED_OFF); 109 return; 110 } 111 112 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 113 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 114 return; 115 } 116 117 brightness = led_get_brightness(led_cdev); 118 if (!brightness) { 119 /* Time to switch the LED on. */ 120 brightness = led_cdev->blink_brightness; 121 delay = led_cdev->blink_delay_on; 122 } else { 123 /* Store the current brightness value to be able 124 * to restore it when the delay_off period is over. 125 */ 126 led_cdev->blink_brightness = brightness; 127 brightness = LED_OFF; 128 delay = led_cdev->blink_delay_off; 129 } 130 131 __led_set_brightness(led_cdev, brightness); 132 133 /* Return in next iteration if led is in one-shot mode and we are in 134 * the final blink state so that the led is toggled each delay_on + 135 * delay_off milliseconds in worst case. 136 */ 137 if (led_cdev->flags & LED_BLINK_ONESHOT) { 138 if (led_cdev->flags & LED_BLINK_INVERT) { 139 if (brightness) 140 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 141 } else { 142 if (!brightness) 143 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 144 } 145 } 146 147 queue_delayed_work(system_wq, &led_cdev->blink_work, 148 msecs_to_jiffies(delay)); 149 } 150 151 static void set_brightness_delayed(struct work_struct *ws) 152 { 153 struct led_classdev *led_cdev = 154 container_of(ws, struct led_classdev, set_brightness_work); 155 156 led_stop_software_blink(led_cdev); 157 158 __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 159 } 160 161 /** 162 * led_classdev_suspend - suspend an led_classdev. 163 * @led_cdev: the led_classdev to suspend. 164 */ 165 void led_classdev_suspend(struct led_classdev *led_cdev) 166 { 167 led_cdev->flags |= LED_SUSPENDED; 168 led_cdev->brightness_set(led_cdev, 0); 169 } 170 EXPORT_SYMBOL_GPL(led_classdev_suspend); 171 172 /** 173 * led_classdev_resume - resume an led_classdev. 174 * @led_cdev: the led_classdev to resume. 175 */ 176 void led_classdev_resume(struct led_classdev *led_cdev) 177 { 178 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 179 led_cdev->flags &= ~LED_SUSPENDED; 180 } 181 EXPORT_SYMBOL_GPL(led_classdev_resume); 182 183 static int led_suspend(struct device *dev) 184 { 185 struct led_classdev *led_cdev = dev_get_drvdata(dev); 186 187 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 188 led_classdev_suspend(led_cdev); 189 190 return 0; 191 } 192 193 static int led_resume(struct device *dev) 194 { 195 struct led_classdev *led_cdev = dev_get_drvdata(dev); 196 197 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 198 led_classdev_resume(led_cdev); 199 200 return 0; 201 } 202 203 static const struct dev_pm_ops leds_class_dev_pm_ops = { 204 .suspend = led_suspend, 205 .resume = led_resume, 206 }; 207 208 /** 209 * led_classdev_register - register a new object of led_classdev class. 210 * @parent: The device to register. 211 * @led_cdev: the led_classdev structure for this device. 212 */ 213 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 214 { 215 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 216 led_cdev, led_cdev->groups, 217 "%s", led_cdev->name); 218 if (IS_ERR(led_cdev->dev)) 219 return PTR_ERR(led_cdev->dev); 220 221 #ifdef CONFIG_LEDS_TRIGGERS 222 init_rwsem(&led_cdev->trigger_lock); 223 #endif 224 /* add to the list of leds */ 225 down_write(&leds_list_lock); 226 list_add_tail(&led_cdev->node, &leds_list); 227 up_write(&leds_list_lock); 228 229 if (!led_cdev->max_brightness) 230 led_cdev->max_brightness = LED_FULL; 231 232 led_update_brightness(led_cdev); 233 234 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 235 236 INIT_DELAYED_WORK(&led_cdev->blink_work, led_work_function); 237 238 #ifdef CONFIG_LEDS_TRIGGERS 239 led_trigger_set_default(led_cdev); 240 #endif 241 242 dev_dbg(parent, "Registered led device: %s\n", 243 led_cdev->name); 244 245 return 0; 246 } 247 EXPORT_SYMBOL_GPL(led_classdev_register); 248 249 /** 250 * led_classdev_unregister - unregisters a object of led_properties class. 251 * @led_cdev: the led device to unregister 252 * 253 * Unregisters a previously registered via led_classdev_register object. 254 */ 255 void led_classdev_unregister(struct led_classdev *led_cdev) 256 { 257 #ifdef CONFIG_LEDS_TRIGGERS 258 down_write(&led_cdev->trigger_lock); 259 if (led_cdev->trigger) 260 led_trigger_set(led_cdev, NULL); 261 up_write(&led_cdev->trigger_lock); 262 #endif 263 264 cancel_work_sync(&led_cdev->set_brightness_work); 265 266 /* Stop blinking */ 267 led_stop_software_blink(led_cdev); 268 led_set_brightness(led_cdev, LED_OFF); 269 270 device_unregister(led_cdev->dev); 271 272 down_write(&leds_list_lock); 273 list_del(&led_cdev->node); 274 up_write(&leds_list_lock); 275 } 276 EXPORT_SYMBOL_GPL(led_classdev_unregister); 277 278 static int __init leds_init(void) 279 { 280 leds_class = class_create(THIS_MODULE, "leds"); 281 if (IS_ERR(leds_class)) 282 return PTR_ERR(leds_class); 283 leds_class->pm = &leds_class_dev_pm_ops; 284 leds_class->dev_groups = led_groups; 285 return 0; 286 } 287 288 static void __exit leds_exit(void) 289 { 290 class_destroy(leds_class); 291 } 292 293 subsys_initcall(leds_init); 294 module_exit(leds_exit); 295 296 MODULE_AUTHOR("John Lenz, Richard Purdie"); 297 MODULE_LICENSE("GPL"); 298 MODULE_DESCRIPTION("LED Class Interface"); 299