1 /* 2 * LED Class Core 3 * 4 * Copyright 2005-2006 Openedhand Ltd. 5 * 6 * Author: Richard Purdie <rpurdie@openedhand.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/leds.h> 16 #include <linux/list.h> 17 #include <linux/module.h> 18 #include <linux/mutex.h> 19 #include <linux/rwsem.h> 20 #include "leds.h" 21 22 DECLARE_RWSEM(leds_list_lock); 23 EXPORT_SYMBOL_GPL(leds_list_lock); 24 25 LIST_HEAD(leds_list); 26 EXPORT_SYMBOL_GPL(leds_list); 27 28 static int __led_set_brightness(struct led_classdev *led_cdev, 29 enum led_brightness value) 30 { 31 if (!led_cdev->brightness_set) 32 return -ENOTSUPP; 33 34 led_cdev->brightness_set(led_cdev, value); 35 36 return 0; 37 } 38 39 static int __led_set_brightness_blocking(struct led_classdev *led_cdev, 40 enum led_brightness value) 41 { 42 if (!led_cdev->brightness_set_blocking) 43 return -ENOTSUPP; 44 45 return led_cdev->brightness_set_blocking(led_cdev, value); 46 } 47 48 static void led_timer_function(unsigned long data) 49 { 50 struct led_classdev *led_cdev = (void *)data; 51 unsigned long brightness; 52 unsigned long delay; 53 54 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 55 led_set_brightness_nosleep(led_cdev, LED_OFF); 56 led_cdev->flags &= ~LED_BLINK_SW; 57 return; 58 } 59 60 if (led_cdev->flags & LED_BLINK_ONESHOT_STOP) { 61 led_cdev->flags &= ~(LED_BLINK_ONESHOT_STOP | LED_BLINK_SW); 62 return; 63 } 64 65 brightness = led_get_brightness(led_cdev); 66 if (!brightness) { 67 /* Time to switch the LED on. */ 68 brightness = led_cdev->blink_brightness; 69 delay = led_cdev->blink_delay_on; 70 } else { 71 /* Store the current brightness value to be able 72 * to restore it when the delay_off period is over. 73 * Do it only if there is no pending blink brightness 74 * change, to avoid overwriting the new value. 75 */ 76 if (!(led_cdev->flags & LED_BLINK_BRIGHTNESS_CHANGE)) 77 led_cdev->blink_brightness = brightness; 78 else 79 led_cdev->flags &= ~LED_BLINK_BRIGHTNESS_CHANGE; 80 brightness = LED_OFF; 81 delay = led_cdev->blink_delay_off; 82 } 83 84 led_set_brightness_nosleep(led_cdev, brightness); 85 86 /* Return in next iteration if led is in one-shot mode and we are in 87 * the final blink state so that the led is toggled each delay_on + 88 * delay_off milliseconds in worst case. 89 */ 90 if (led_cdev->flags & LED_BLINK_ONESHOT) { 91 if (led_cdev->flags & LED_BLINK_INVERT) { 92 if (brightness) 93 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 94 } else { 95 if (!brightness) 96 led_cdev->flags |= LED_BLINK_ONESHOT_STOP; 97 } 98 } 99 100 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 101 } 102 103 static void set_brightness_delayed(struct work_struct *ws) 104 { 105 struct led_classdev *led_cdev = 106 container_of(ws, struct led_classdev, set_brightness_work); 107 int ret = 0; 108 109 if (led_cdev->flags & LED_BLINK_DISABLE) { 110 led_cdev->delayed_set_value = LED_OFF; 111 led_stop_software_blink(led_cdev); 112 led_cdev->flags &= ~LED_BLINK_DISABLE; 113 } 114 115 ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 116 if (ret == -ENOTSUPP) 117 ret = __led_set_brightness_blocking(led_cdev, 118 led_cdev->delayed_set_value); 119 if (ret < 0 && 120 /* LED HW might have been unplugged, therefore don't warn */ 121 !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && 122 (led_cdev->flags & LED_HW_PLUGGABLE))) 123 dev_err(led_cdev->dev, 124 "Setting an LED's brightness failed (%d)\n", ret); 125 } 126 127 static void led_set_software_blink(struct led_classdev *led_cdev, 128 unsigned long delay_on, 129 unsigned long delay_off) 130 { 131 int current_brightness; 132 133 current_brightness = led_get_brightness(led_cdev); 134 if (current_brightness) 135 led_cdev->blink_brightness = current_brightness; 136 if (!led_cdev->blink_brightness) 137 led_cdev->blink_brightness = led_cdev->max_brightness; 138 139 led_cdev->blink_delay_on = delay_on; 140 led_cdev->blink_delay_off = delay_off; 141 142 /* never on - just set to off */ 143 if (!delay_on) { 144 led_set_brightness_nosleep(led_cdev, LED_OFF); 145 return; 146 } 147 148 /* never off - just set to brightness */ 149 if (!delay_off) { 150 led_set_brightness_nosleep(led_cdev, 151 led_cdev->blink_brightness); 152 return; 153 } 154 155 led_cdev->flags |= LED_BLINK_SW; 156 mod_timer(&led_cdev->blink_timer, jiffies + 1); 157 } 158 159 160 static void led_blink_setup(struct led_classdev *led_cdev, 161 unsigned long *delay_on, 162 unsigned long *delay_off) 163 { 164 if (!(led_cdev->flags & LED_BLINK_ONESHOT) && 165 led_cdev->blink_set && 166 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 167 return; 168 169 /* blink with 1 Hz as default if nothing specified */ 170 if (!*delay_on && !*delay_off) 171 *delay_on = *delay_off = 500; 172 173 led_set_software_blink(led_cdev, *delay_on, *delay_off); 174 } 175 176 void led_init_core(struct led_classdev *led_cdev) 177 { 178 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 179 180 setup_timer(&led_cdev->blink_timer, led_timer_function, 181 (unsigned long)led_cdev); 182 } 183 EXPORT_SYMBOL_GPL(led_init_core); 184 185 void led_blink_set(struct led_classdev *led_cdev, 186 unsigned long *delay_on, 187 unsigned long *delay_off) 188 { 189 del_timer_sync(&led_cdev->blink_timer); 190 191 led_cdev->flags &= ~LED_BLINK_ONESHOT; 192 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 193 194 led_blink_setup(led_cdev, delay_on, delay_off); 195 } 196 EXPORT_SYMBOL_GPL(led_blink_set); 197 198 void led_blink_set_oneshot(struct led_classdev *led_cdev, 199 unsigned long *delay_on, 200 unsigned long *delay_off, 201 int invert) 202 { 203 if ((led_cdev->flags & LED_BLINK_ONESHOT) && 204 timer_pending(&led_cdev->blink_timer)) 205 return; 206 207 led_cdev->flags |= LED_BLINK_ONESHOT; 208 led_cdev->flags &= ~LED_BLINK_ONESHOT_STOP; 209 210 if (invert) 211 led_cdev->flags |= LED_BLINK_INVERT; 212 else 213 led_cdev->flags &= ~LED_BLINK_INVERT; 214 215 led_blink_setup(led_cdev, delay_on, delay_off); 216 } 217 EXPORT_SYMBOL_GPL(led_blink_set_oneshot); 218 219 void led_stop_software_blink(struct led_classdev *led_cdev) 220 { 221 del_timer_sync(&led_cdev->blink_timer); 222 led_cdev->blink_delay_on = 0; 223 led_cdev->blink_delay_off = 0; 224 led_cdev->flags &= ~LED_BLINK_SW; 225 } 226 EXPORT_SYMBOL_GPL(led_stop_software_blink); 227 228 void led_set_brightness(struct led_classdev *led_cdev, 229 enum led_brightness brightness) 230 { 231 /* 232 * If software blink is active, delay brightness setting 233 * until the next timer tick. 234 */ 235 if (led_cdev->flags & LED_BLINK_SW) { 236 /* 237 * If we need to disable soft blinking delegate this to the 238 * work queue task to avoid problems in case we are called 239 * from hard irq context. 240 */ 241 if (brightness == LED_OFF) { 242 led_cdev->flags |= LED_BLINK_DISABLE; 243 schedule_work(&led_cdev->set_brightness_work); 244 } else { 245 led_cdev->flags |= LED_BLINK_BRIGHTNESS_CHANGE; 246 led_cdev->blink_brightness = brightness; 247 } 248 return; 249 } 250 251 led_set_brightness_nosleep(led_cdev, brightness); 252 } 253 EXPORT_SYMBOL_GPL(led_set_brightness); 254 255 void led_set_brightness_nopm(struct led_classdev *led_cdev, 256 enum led_brightness value) 257 { 258 /* Use brightness_set op if available, it is guaranteed not to sleep */ 259 if (!__led_set_brightness(led_cdev, value)) 260 return; 261 262 /* If brightness setting can sleep, delegate it to a work queue task */ 263 led_cdev->delayed_set_value = value; 264 schedule_work(&led_cdev->set_brightness_work); 265 } 266 EXPORT_SYMBOL_GPL(led_set_brightness_nopm); 267 268 void led_set_brightness_nosleep(struct led_classdev *led_cdev, 269 enum led_brightness value) 270 { 271 led_cdev->brightness = min(value, led_cdev->max_brightness); 272 273 if (led_cdev->flags & LED_SUSPENDED) 274 return; 275 276 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 277 } 278 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); 279 280 int led_set_brightness_sync(struct led_classdev *led_cdev, 281 enum led_brightness value) 282 { 283 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) 284 return -EBUSY; 285 286 led_cdev->brightness = min(value, led_cdev->max_brightness); 287 288 if (led_cdev->flags & LED_SUSPENDED) 289 return 0; 290 291 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness); 292 } 293 EXPORT_SYMBOL_GPL(led_set_brightness_sync); 294 295 int led_update_brightness(struct led_classdev *led_cdev) 296 { 297 int ret = 0; 298 299 if (led_cdev->brightness_get) { 300 ret = led_cdev->brightness_get(led_cdev); 301 if (ret >= 0) { 302 led_cdev->brightness = ret; 303 return 0; 304 } 305 } 306 307 return ret; 308 } 309 EXPORT_SYMBOL_GPL(led_update_brightness); 310 311 /* Caller must ensure led_cdev->led_access held */ 312 void led_sysfs_disable(struct led_classdev *led_cdev) 313 { 314 lockdep_assert_held(&led_cdev->led_access); 315 316 led_cdev->flags |= LED_SYSFS_DISABLE; 317 } 318 EXPORT_SYMBOL_GPL(led_sysfs_disable); 319 320 /* Caller must ensure led_cdev->led_access held */ 321 void led_sysfs_enable(struct led_classdev *led_cdev) 322 { 323 lockdep_assert_held(&led_cdev->led_access); 324 325 led_cdev->flags &= ~LED_SYSFS_DISABLE; 326 } 327 EXPORT_SYMBOL_GPL(led_sysfs_enable); 328