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/sysdev.h> 19 #include <linux/timer.h> 20 #include <linux/err.h> 21 #include <linux/ctype.h> 22 #include <linux/leds.h> 23 #include "leds.h" 24 25 static struct class *leds_class; 26 27 static void led_update_brightness(struct led_classdev *led_cdev) 28 { 29 if (led_cdev->brightness_get) 30 led_cdev->brightness = led_cdev->brightness_get(led_cdev); 31 } 32 33 static ssize_t led_brightness_show(struct device *dev, 34 struct device_attribute *attr, char *buf) 35 { 36 struct led_classdev *led_cdev = dev_get_drvdata(dev); 37 38 /* no lock needed for this */ 39 led_update_brightness(led_cdev); 40 41 return sprintf(buf, "%u\n", led_cdev->brightness); 42 } 43 44 static ssize_t led_brightness_store(struct device *dev, 45 struct device_attribute *attr, const char *buf, size_t size) 46 { 47 struct led_classdev *led_cdev = dev_get_drvdata(dev); 48 ssize_t ret = -EINVAL; 49 char *after; 50 unsigned long state = simple_strtoul(buf, &after, 10); 51 size_t count = after - buf; 52 53 if (isspace(*after)) 54 count++; 55 56 if (count == size) { 57 ret = count; 58 59 if (state == LED_OFF) 60 led_trigger_remove(led_cdev); 61 led_set_brightness(led_cdev, state); 62 } 63 64 return ret; 65 } 66 67 static ssize_t led_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 75 static struct device_attribute led_class_attrs[] = { 76 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store), 77 __ATTR(max_brightness, 0444, led_max_brightness_show, NULL), 78 #ifdef CONFIG_LEDS_TRIGGERS 79 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store), 80 #endif 81 __ATTR_NULL, 82 }; 83 84 static void led_timer_function(unsigned long data) 85 { 86 struct led_classdev *led_cdev = (void *)data; 87 unsigned long brightness; 88 unsigned long delay; 89 90 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 91 led_set_brightness(led_cdev, LED_OFF); 92 return; 93 } 94 95 brightness = led_get_brightness(led_cdev); 96 if (!brightness) { 97 /* Time to switch the LED on. */ 98 brightness = led_cdev->blink_brightness; 99 delay = led_cdev->blink_delay_on; 100 } else { 101 /* Store the current brightness value to be able 102 * to restore it when the delay_off period is over. 103 */ 104 led_cdev->blink_brightness = brightness; 105 brightness = LED_OFF; 106 delay = led_cdev->blink_delay_off; 107 } 108 109 led_set_brightness(led_cdev, brightness); 110 111 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 112 } 113 114 static void led_stop_software_blink(struct led_classdev *led_cdev) 115 { 116 /* deactivate previous settings */ 117 del_timer_sync(&led_cdev->blink_timer); 118 led_cdev->blink_delay_on = 0; 119 led_cdev->blink_delay_off = 0; 120 } 121 122 static void led_set_software_blink(struct led_classdev *led_cdev, 123 unsigned long delay_on, 124 unsigned long delay_off) 125 { 126 int current_brightness; 127 128 current_brightness = led_get_brightness(led_cdev); 129 if (current_brightness) 130 led_cdev->blink_brightness = current_brightness; 131 if (!led_cdev->blink_brightness) 132 led_cdev->blink_brightness = led_cdev->max_brightness; 133 134 if (led_get_trigger_data(led_cdev) && 135 delay_on == led_cdev->blink_delay_on && 136 delay_off == led_cdev->blink_delay_off) 137 return; 138 139 led_stop_software_blink(led_cdev); 140 141 led_cdev->blink_delay_on = delay_on; 142 led_cdev->blink_delay_off = delay_off; 143 144 /* never on - don't blink */ 145 if (!delay_on) 146 return; 147 148 /* never off - just set to brightness */ 149 if (!delay_off) { 150 led_set_brightness(led_cdev, led_cdev->blink_brightness); 151 return; 152 } 153 154 mod_timer(&led_cdev->blink_timer, jiffies + 1); 155 } 156 157 158 /** 159 * led_classdev_suspend - suspend an led_classdev. 160 * @led_cdev: the led_classdev to suspend. 161 */ 162 void led_classdev_suspend(struct led_classdev *led_cdev) 163 { 164 led_cdev->flags |= LED_SUSPENDED; 165 led_cdev->brightness_set(led_cdev, 0); 166 } 167 EXPORT_SYMBOL_GPL(led_classdev_suspend); 168 169 /** 170 * led_classdev_resume - resume an led_classdev. 171 * @led_cdev: the led_classdev to resume. 172 */ 173 void led_classdev_resume(struct led_classdev *led_cdev) 174 { 175 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 176 led_cdev->flags &= ~LED_SUSPENDED; 177 } 178 EXPORT_SYMBOL_GPL(led_classdev_resume); 179 180 static int led_suspend(struct device *dev, pm_message_t state) 181 { 182 struct led_classdev *led_cdev = dev_get_drvdata(dev); 183 184 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 185 led_classdev_suspend(led_cdev); 186 187 return 0; 188 } 189 190 static int led_resume(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_resume(led_cdev); 196 197 return 0; 198 } 199 200 /** 201 * led_classdev_register - register a new object of led_classdev class. 202 * @parent: The device to register. 203 * @led_cdev: the led_classdev structure for this device. 204 */ 205 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 206 { 207 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 208 "%s", led_cdev->name); 209 if (IS_ERR(led_cdev->dev)) 210 return PTR_ERR(led_cdev->dev); 211 212 #ifdef CONFIG_LEDS_TRIGGERS 213 init_rwsem(&led_cdev->trigger_lock); 214 #endif 215 /* add to the list of leds */ 216 down_write(&leds_list_lock); 217 list_add_tail(&led_cdev->node, &leds_list); 218 up_write(&leds_list_lock); 219 220 if (!led_cdev->max_brightness) 221 led_cdev->max_brightness = LED_FULL; 222 223 led_update_brightness(led_cdev); 224 225 init_timer(&led_cdev->blink_timer); 226 led_cdev->blink_timer.function = led_timer_function; 227 led_cdev->blink_timer.data = (unsigned long)led_cdev; 228 229 #ifdef CONFIG_LEDS_TRIGGERS 230 led_trigger_set_default(led_cdev); 231 #endif 232 233 printk(KERN_DEBUG "Registered led device: %s\n", 234 led_cdev->name); 235 236 return 0; 237 } 238 EXPORT_SYMBOL_GPL(led_classdev_register); 239 240 /** 241 * led_classdev_unregister - unregisters a object of led_properties class. 242 * @led_cdev: the led device to unregister 243 * 244 * Unregisters a previously registered via led_classdev_register object. 245 */ 246 void led_classdev_unregister(struct led_classdev *led_cdev) 247 { 248 #ifdef CONFIG_LEDS_TRIGGERS 249 down_write(&led_cdev->trigger_lock); 250 if (led_cdev->trigger) 251 led_trigger_set(led_cdev, NULL); 252 up_write(&led_cdev->trigger_lock); 253 #endif 254 255 /* Stop blinking */ 256 led_brightness_set(led_cdev, LED_OFF); 257 258 device_unregister(led_cdev->dev); 259 260 down_write(&leds_list_lock); 261 list_del(&led_cdev->node); 262 up_write(&leds_list_lock); 263 } 264 EXPORT_SYMBOL_GPL(led_classdev_unregister); 265 266 void led_blink_set(struct led_classdev *led_cdev, 267 unsigned long *delay_on, 268 unsigned long *delay_off) 269 { 270 if (led_cdev->blink_set && 271 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 272 return; 273 274 /* blink with 1 Hz as default if nothing specified */ 275 if (!*delay_on && !*delay_off) 276 *delay_on = *delay_off = 500; 277 278 led_set_software_blink(led_cdev, *delay_on, *delay_off); 279 } 280 EXPORT_SYMBOL(led_blink_set); 281 282 void led_brightness_set(struct led_classdev *led_cdev, 283 enum led_brightness brightness) 284 { 285 led_stop_software_blink(led_cdev); 286 led_cdev->brightness_set(led_cdev, brightness); 287 } 288 EXPORT_SYMBOL(led_brightness_set); 289 290 static int __init leds_init(void) 291 { 292 leds_class = class_create(THIS_MODULE, "leds"); 293 if (IS_ERR(leds_class)) 294 return PTR_ERR(leds_class); 295 leds_class->suspend = led_suspend; 296 leds_class->resume = led_resume; 297 leds_class->dev_attrs = led_class_attrs; 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