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