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 (delay_on == led_cdev->blink_delay_on && 135 delay_off == led_cdev->blink_delay_off) 136 return; 137 138 led_stop_software_blink(led_cdev); 139 140 led_cdev->blink_delay_on = delay_on; 141 led_cdev->blink_delay_off = delay_off; 142 143 /* never on - don't blink */ 144 if (!delay_on) 145 return; 146 147 /* never off - just set to brightness */ 148 if (!delay_off) { 149 led_set_brightness(led_cdev, led_cdev->blink_brightness); 150 return; 151 } 152 153 mod_timer(&led_cdev->blink_timer, jiffies + 1); 154 } 155 156 157 /** 158 * led_classdev_suspend - suspend an led_classdev. 159 * @led_cdev: the led_classdev to suspend. 160 */ 161 void led_classdev_suspend(struct led_classdev *led_cdev) 162 { 163 led_cdev->flags |= LED_SUSPENDED; 164 led_cdev->brightness_set(led_cdev, 0); 165 } 166 EXPORT_SYMBOL_GPL(led_classdev_suspend); 167 168 /** 169 * led_classdev_resume - resume an led_classdev. 170 * @led_cdev: the led_classdev to resume. 171 */ 172 void led_classdev_resume(struct led_classdev *led_cdev) 173 { 174 led_cdev->brightness_set(led_cdev, led_cdev->brightness); 175 led_cdev->flags &= ~LED_SUSPENDED; 176 } 177 EXPORT_SYMBOL_GPL(led_classdev_resume); 178 179 static int led_suspend(struct device *dev, pm_message_t state) 180 { 181 struct led_classdev *led_cdev = dev_get_drvdata(dev); 182 183 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 184 led_classdev_suspend(led_cdev); 185 186 return 0; 187 } 188 189 static int led_resume(struct device *dev) 190 { 191 struct led_classdev *led_cdev = dev_get_drvdata(dev); 192 193 if (led_cdev->flags & LED_CORE_SUSPENDRESUME) 194 led_classdev_resume(led_cdev); 195 196 return 0; 197 } 198 199 /** 200 * led_classdev_register - register a new object of led_classdev class. 201 * @parent: The device to register. 202 * @led_cdev: the led_classdev structure for this device. 203 */ 204 int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 205 { 206 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 207 "%s", led_cdev->name); 208 if (IS_ERR(led_cdev->dev)) 209 return PTR_ERR(led_cdev->dev); 210 211 #ifdef CONFIG_LEDS_TRIGGERS 212 init_rwsem(&led_cdev->trigger_lock); 213 #endif 214 /* add to the list of leds */ 215 down_write(&leds_list_lock); 216 list_add_tail(&led_cdev->node, &leds_list); 217 up_write(&leds_list_lock); 218 219 if (!led_cdev->max_brightness) 220 led_cdev->max_brightness = LED_FULL; 221 222 led_update_brightness(led_cdev); 223 224 init_timer(&led_cdev->blink_timer); 225 led_cdev->blink_timer.function = led_timer_function; 226 led_cdev->blink_timer.data = (unsigned long)led_cdev; 227 228 #ifdef CONFIG_LEDS_TRIGGERS 229 led_trigger_set_default(led_cdev); 230 #endif 231 232 printk(KERN_DEBUG "Registered led device: %s\n", 233 led_cdev->name); 234 235 return 0; 236 } 237 EXPORT_SYMBOL_GPL(led_classdev_register); 238 239 /** 240 * led_classdev_unregister - unregisters a object of led_properties class. 241 * @led_cdev: the led device to unregister 242 * 243 * Unregisters a previously registered via led_classdev_register object. 244 */ 245 void led_classdev_unregister(struct led_classdev *led_cdev) 246 { 247 #ifdef CONFIG_LEDS_TRIGGERS 248 down_write(&led_cdev->trigger_lock); 249 if (led_cdev->trigger) 250 led_trigger_set(led_cdev, NULL); 251 up_write(&led_cdev->trigger_lock); 252 #endif 253 254 /* Stop blinking */ 255 led_brightness_set(led_cdev, LED_OFF); 256 257 device_unregister(led_cdev->dev); 258 259 down_write(&leds_list_lock); 260 list_del(&led_cdev->node); 261 up_write(&leds_list_lock); 262 } 263 EXPORT_SYMBOL_GPL(led_classdev_unregister); 264 265 void led_blink_set(struct led_classdev *led_cdev, 266 unsigned long *delay_on, 267 unsigned long *delay_off) 268 { 269 if (led_cdev->blink_set && 270 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 271 return; 272 273 /* blink with 1 Hz as default if nothing specified */ 274 if (!*delay_on && !*delay_off) 275 *delay_on = *delay_off = 500; 276 277 led_set_software_blink(led_cdev, *delay_on, *delay_off); 278 } 279 EXPORT_SYMBOL(led_blink_set); 280 281 void led_brightness_set(struct led_classdev *led_cdev, 282 enum led_brightness brightness) 283 { 284 led_stop_software_blink(led_cdev); 285 led_cdev->brightness_set(led_cdev, brightness); 286 } 287 EXPORT_SYMBOL(led_brightness_set); 288 289 static int __init leds_init(void) 290 { 291 leds_class = class_create(THIS_MODULE, "leds"); 292 if (IS_ERR(leds_class)) 293 return PTR_ERR(leds_class); 294 leds_class->suspend = led_suspend; 295 leds_class->resume = led_resume; 296 leds_class->dev_attrs = led_class_attrs; 297 return 0; 298 } 299 300 static void __exit leds_exit(void) 301 { 302 class_destroy(leds_class); 303 } 304 305 subsys_initcall(leds_init); 306 module_exit(leds_exit); 307 308 MODULE_AUTHOR("John Lenz, Richard Purdie"); 309 MODULE_LICENSE("GPL"); 310 MODULE_DESCRIPTION("LED Class Interface"); 311