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/ctype.h> 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/kernel.h> 17 #include <linux/leds.h> 18 #include <linux/list.h> 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 #include <linux/spinlock.h> 22 #include <linux/timer.h> 23 #include "leds.h" 24 25 static struct class *leds_class; 26 27 static ssize_t brightness_show(struct device *dev, 28 struct device_attribute *attr, char *buf) 29 { 30 struct led_classdev *led_cdev = dev_get_drvdata(dev); 31 32 /* no lock needed for this */ 33 led_update_brightness(led_cdev); 34 35 return sprintf(buf, "%u\n", led_cdev->brightness); 36 } 37 38 static ssize_t brightness_store(struct device *dev, 39 struct device_attribute *attr, const char *buf, size_t size) 40 { 41 struct led_classdev *led_cdev = dev_get_drvdata(dev); 42 unsigned long state; 43 ssize_t ret; 44 45 mutex_lock(&led_cdev->led_access); 46 47 if (led_sysfs_is_disabled(led_cdev)) { 48 ret = -EBUSY; 49 goto unlock; 50 } 51 52 ret = kstrtoul(buf, 10, &state); 53 if (ret) 54 goto unlock; 55 56 if (state == LED_OFF) 57 led_trigger_remove(led_cdev); 58 led_set_brightness(led_cdev, state); 59 60 ret = size; 61 unlock: 62 mutex_unlock(&led_cdev->led_access); 63 return ret; 64 } 65 static DEVICE_ATTR_RW(brightness); 66 67 static ssize_t max_brightness_show(struct device *dev, 68 struct device_attribute *attr, char *buf) 69 { 70 struct led_classdev *led_cdev = dev_get_drvdata(dev); 71 72 return sprintf(buf, "%u\n", led_cdev->max_brightness); 73 } 74 static DEVICE_ATTR_RO(max_brightness); 75 76 #ifdef CONFIG_LEDS_TRIGGERS 77 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 78 static struct attribute *led_trigger_attrs[] = { 79 &dev_attr_trigger.attr, 80 NULL, 81 }; 82 static const struct attribute_group led_trigger_group = { 83 .attrs = led_trigger_attrs, 84 }; 85 #endif 86 87 static struct attribute *led_class_attrs[] = { 88 &dev_attr_brightness.attr, 89 &dev_attr_max_brightness.attr, 90 NULL, 91 }; 92 93 static const struct attribute_group led_group = { 94 .attrs = led_class_attrs, 95 }; 96 97 static const struct attribute_group *led_groups[] = { 98 &led_group, 99 #ifdef CONFIG_LEDS_TRIGGERS 100 &led_trigger_group, 101 #endif 102 NULL, 103 }; 104 105 static void led_timer_function(unsigned long data) 106 { 107 struct led_classdev *led_cdev = (void *)data; 108 unsigned long brightness; 109 unsigned long delay; 110 111 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 112 led_set_brightness_async(led_cdev, LED_OFF); 113 return; 114 } 115 116 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 117 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 118 return; 119 } 120 121 brightness = led_get_brightness(led_cdev); 122 if (!brightness) { 123 /* Time to switch the LED on. */ 124 brightness = led_cdev->blink_brightness; 125 delay = led_cdev->blink_delay_on; 126 } else { 127 /* Store the current brightness value to be able 128 * to restore it when the delay_off period is over. 129 */ 130 led_cdev->blink_brightness = brightness; 131 brightness = LED_OFF; 132 delay = led_cdev->blink_delay_off; 133 } 134 135 led_set_brightness_async(led_cdev, brightness); 136 137 /* Return in next iteration if led is in one-shot mode and we are in 138 * the final blink state so that the led is toggled each delay_on + 139 * delay_off milliseconds in worst case. 140 */ 141 if (led_cdev->flags & LED_BLINK_ONESHOT) { 142 if (led_cdev->flags & LED_BLINK_INVERT) { 143 if (brightness) 144 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 145 } else { 146 if (!brightness) 147 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 148 } 149 } 150 151 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 152 } 153 154 static void set_brightness_delayed(struct work_struct *ws) 155 { 156 struct led_classdev *led_cdev = 157 container_of(ws, struct led_classdev, set_brightness_work); 158 159 led_stop_software_blink(led_cdev); 160 161 led_set_brightness_async(led_cdev, led_cdev->delayed_set_value); 162 } 163 164 /** 165 * led_classdev_suspend - suspend an led_classdev. 166 * @led_cdev: the led_classdev to suspend. 167 */ 168 void led_classdev_suspend(struct led_classdev *led_cdev) 169 { 170 led_cdev->flags |= LED_SUSPENDED; 171 led_cdev->brightness_set(led_cdev, 0); 172 } 173 EXPORT_SYMBOL_GPL(led_classdev_suspend); 174 175 /** 176 * led_classdev_resume - resume an led_classdev. 177 * @led_cdev: the led_classdev to resume. 178 */ 179 void led_classdev_resume(struct led_classdev *led_cdev) 180 { 181 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 182 183 if (led_cdev->flash_resume) 184 led_cdev->flash_resume(led_cdev); 185 186 led_cdev->flags &= ~LED_SUSPENDED; 187 } 188 EXPORT_SYMBOL_GPL(led_classdev_resume); 189 190 static int led_suspend(struct device *dev) 191 { 192 struct led_classdev *led_cdev = dev_get_drvdata(dev); 193 194 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 195 led_classdev_suspend(led_cdev); 196 197 return 0; 198 } 199 200 static int led_resume(struct device *dev) 201 { 202 struct led_classdev *led_cdev = dev_get_drvdata(dev); 203 204 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 205 led_classdev_resume(led_cdev); 206 207 return 0; 208 } 209 210 static const struct dev_pm_ops leds_class_dev_pm_ops = { 211 .suspend = led_suspend, 212 .resume = led_resume, 213 }; 214 215 /** 216 * led_classdev_register - register a new object of led_classdev class. 217 * @parent: The device to register. 218 * @led_cdev: the led_classdev structure for this device. 219 */ 220 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 221 { 222 led_cdev->dev = device_create_with_groups(leds_class, parent, 0, 223 led_cdev, led_cdev->groups, 224 "%s", led_cdev->name); 225 if (IS_ERR(led_cdev->dev)) 226 return PTR_ERR(led_cdev->dev); 227 228 #ifdef CONFIG_LEDS_TRIGGERS 229 init_rwsem(&led_cdev->trigger_lock); 230 #endif 231 mutex_init(&led_cdev->led_access); 232 /* add to the list of leds */ 233 down_write(&leds_list_lock); 234 list_add_tail(&led_cdev->node, &leds_list); 235 up_write(&leds_list_lock); 236 237 if (!led_cdev->max_brightness) 238 led_cdev->max_brightness = LED_FULL; 239 240 led_cdev->flags |= SET_BRIGHTNESS_ASYNC; 241 242 led_update_brightness(led_cdev); 243 244 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 245 246 setup_timer(&led_cdev->blink_timer, led_timer_function, 247 (unsigned long)led_cdev); 248 249 #ifdef CONFIG_LEDS_TRIGGERS 250 led_trigger_set_default(led_cdev); 251 #endif 252 253 dev_dbg(parent, "Registered led device: %s\n", 254 led_cdev->name); 255 256 return 0; 257 } 258 EXPORT_SYMBOL_GPL(led_classdev_register); 259 260 /** 261 * led_classdev_unregister - unregisters a object of led_properties class. 262 * @led_cdev: the led device to unregister 263 * 264 * Unregisters a previously registered via led_classdev_register object. 265 */ 266 void led_classdev_unregister(struct led_classdev *led_cdev) 267 { 268 #ifdef CONFIG_LEDS_TRIGGERS 269 down_write(&led_cdev->trigger_lock); 270 if (led_cdev->trigger) 271 led_trigger_set(led_cdev, NULL); 272 up_write(&led_cdev->trigger_lock); 273 #endif 274 275 cancel_work_sync(&led_cdev->set_brightness_work); 276 277 /* Stop blinking */ 278 led_stop_software_blink(led_cdev); 279 led_set_brightness(led_cdev, LED_OFF); 280 281 device_unregister(led_cdev->dev); 282 283 down_write(&leds_list_lock); 284 list_del(&led_cdev->node); 285 up_write(&leds_list_lock); 286 287 mutex_destroy(&led_cdev->led_access); 288 } 289 EXPORT_SYMBOL_GPL(led_classdev_unregister); 290 291 static int __init leds_init(void) 292 { 293 leds_class = class_create(THIS_MODULE, "leds"); 294 if (IS_ERR(leds_class)) 295 return PTR_ERR(leds_class); 296 leds_class->pm = &leds_class_dev_pm_ops; 297 leds_class->dev_groups = led_groups; 298 return 0; 299 } 300 301 static void __exit leds_exit(void) 302 { 303 class_destroy(leds_class); 304 } 305 306 subsys_initcall(leds_init); 307 module_exit(leds_exit); 308 309 MODULE_AUTHOR("John Lenz, Richard Purdie"); 310 MODULE_LICENSE("GPL"); 311 MODULE_DESCRIPTION("LED Class Interface"); 312