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 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 57 return; 58 } 59 60 if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP, 61 &led_cdev->work_flags)) { 62 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 63 return; 64 } 65 66 brightness = led_get_brightness(led_cdev); 67 if (!brightness) { 68 /* Time to switch the LED on. */ 69 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, 70 &led_cdev->work_flags)) 71 brightness = led_cdev->new_blink_brightness; 72 else 73 brightness = led_cdev->blink_brightness; 74 delay = led_cdev->blink_delay_on; 75 } else { 76 /* Store the current brightness value to be able 77 * to restore it when the delay_off period is over. 78 */ 79 led_cdev->blink_brightness = brightness; 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 (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) { 91 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) { 92 if (brightness) 93 set_bit(LED_BLINK_ONESHOT_STOP, 94 &led_cdev->work_flags); 95 } else { 96 if (!brightness) 97 set_bit(LED_BLINK_ONESHOT_STOP, 98 &led_cdev->work_flags); 99 } 100 } 101 102 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 103 } 104 105 static void set_brightness_delayed(struct work_struct *ws) 106 { 107 struct led_classdev *led_cdev = 108 container_of(ws, struct led_classdev, set_brightness_work); 109 int ret = 0; 110 111 if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { 112 led_cdev->delayed_set_value = LED_OFF; 113 led_stop_software_blink(led_cdev); 114 } 115 116 ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 117 if (ret == -ENOTSUPP) 118 ret = __led_set_brightness_blocking(led_cdev, 119 led_cdev->delayed_set_value); 120 if (ret < 0 && 121 /* LED HW might have been unplugged, therefore don't warn */ 122 !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && 123 (led_cdev->flags & LED_HW_PLUGGABLE))) 124 dev_err(led_cdev->dev, 125 "Setting an LED's brightness failed (%d)\n", ret); 126 } 127 128 static void led_set_software_blink(struct led_classdev *led_cdev, 129 unsigned long delay_on, 130 unsigned long delay_off) 131 { 132 int current_brightness; 133 134 current_brightness = led_get_brightness(led_cdev); 135 if (current_brightness) 136 led_cdev->blink_brightness = current_brightness; 137 if (!led_cdev->blink_brightness) 138 led_cdev->blink_brightness = led_cdev->max_brightness; 139 140 led_cdev->blink_delay_on = delay_on; 141 led_cdev->blink_delay_off = delay_off; 142 143 /* never on - just set to off */ 144 if (!delay_on) { 145 led_set_brightness_nosleep(led_cdev, LED_OFF); 146 return; 147 } 148 149 /* never off - just set to brightness */ 150 if (!delay_off) { 151 led_set_brightness_nosleep(led_cdev, 152 led_cdev->blink_brightness); 153 return; 154 } 155 156 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 157 mod_timer(&led_cdev->blink_timer, jiffies + 1); 158 } 159 160 161 static void led_blink_setup(struct led_classdev *led_cdev, 162 unsigned long *delay_on, 163 unsigned long *delay_off) 164 { 165 if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 166 led_cdev->blink_set && 167 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 168 return; 169 170 /* blink with 1 Hz as default if nothing specified */ 171 if (!*delay_on && !*delay_off) 172 *delay_on = *delay_off = 500; 173 174 led_set_software_blink(led_cdev, *delay_on, *delay_off); 175 } 176 177 void led_init_core(struct led_classdev *led_cdev) 178 { 179 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 180 181 setup_timer(&led_cdev->blink_timer, led_timer_function, 182 (unsigned long)led_cdev); 183 } 184 EXPORT_SYMBOL_GPL(led_init_core); 185 186 void led_blink_set(struct led_classdev *led_cdev, 187 unsigned long *delay_on, 188 unsigned long *delay_off) 189 { 190 del_timer_sync(&led_cdev->blink_timer); 191 192 clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 193 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 194 195 led_blink_setup(led_cdev, delay_on, delay_off); 196 } 197 EXPORT_SYMBOL_GPL(led_blink_set); 198 199 void led_blink_set_oneshot(struct led_classdev *led_cdev, 200 unsigned long *delay_on, 201 unsigned long *delay_off, 202 int invert) 203 { 204 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 205 timer_pending(&led_cdev->blink_timer)) 206 return; 207 208 set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 209 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 210 211 if (invert) 212 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 213 else 214 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 215 216 led_blink_setup(led_cdev, delay_on, delay_off); 217 } 218 EXPORT_SYMBOL_GPL(led_blink_set_oneshot); 219 220 void led_stop_software_blink(struct led_classdev *led_cdev) 221 { 222 del_timer_sync(&led_cdev->blink_timer); 223 led_cdev->blink_delay_on = 0; 224 led_cdev->blink_delay_off = 0; 225 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 226 } 227 EXPORT_SYMBOL_GPL(led_stop_software_blink); 228 229 void led_set_brightness(struct led_classdev *led_cdev, 230 enum led_brightness brightness) 231 { 232 /* 233 * If software blink is active, delay brightness setting 234 * until the next timer tick. 235 */ 236 if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { 237 /* 238 * If we need to disable soft blinking delegate this to the 239 * work queue task to avoid problems in case we are called 240 * from hard irq context. 241 */ 242 if (brightness == LED_OFF) { 243 set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); 244 schedule_work(&led_cdev->set_brightness_work); 245 } else { 246 set_bit(LED_BLINK_BRIGHTNESS_CHANGE, 247 &led_cdev->work_flags); 248 led_cdev->new_blink_brightness = brightness; 249 } 250 return; 251 } 252 253 led_set_brightness_nosleep(led_cdev, brightness); 254 } 255 EXPORT_SYMBOL_GPL(led_set_brightness); 256 257 void led_set_brightness_nopm(struct led_classdev *led_cdev, 258 enum led_brightness value) 259 { 260 /* Use brightness_set op if available, it is guaranteed not to sleep */ 261 if (!__led_set_brightness(led_cdev, value)) 262 return; 263 264 /* If brightness setting can sleep, delegate it to a work queue task */ 265 led_cdev->delayed_set_value = value; 266 schedule_work(&led_cdev->set_brightness_work); 267 } 268 EXPORT_SYMBOL_GPL(led_set_brightness_nopm); 269 270 void led_set_brightness_nosleep(struct led_classdev *led_cdev, 271 enum led_brightness value) 272 { 273 led_cdev->brightness = min(value, led_cdev->max_brightness); 274 275 if (led_cdev->flags & LED_SUSPENDED) 276 return; 277 278 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 279 } 280 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); 281 282 int led_set_brightness_sync(struct led_classdev *led_cdev, 283 enum led_brightness value) 284 { 285 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) 286 return -EBUSY; 287 288 led_cdev->brightness = min(value, led_cdev->max_brightness); 289 290 if (led_cdev->flags & LED_SUSPENDED) 291 return 0; 292 293 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness); 294 } 295 EXPORT_SYMBOL_GPL(led_set_brightness_sync); 296 297 int led_update_brightness(struct led_classdev *led_cdev) 298 { 299 int ret = 0; 300 301 if (led_cdev->brightness_get) { 302 ret = led_cdev->brightness_get(led_cdev); 303 if (ret >= 0) { 304 led_cdev->brightness = ret; 305 return 0; 306 } 307 } 308 309 return ret; 310 } 311 EXPORT_SYMBOL_GPL(led_update_brightness); 312 313 /* Caller must ensure led_cdev->led_access held */ 314 void led_sysfs_disable(struct led_classdev *led_cdev) 315 { 316 lockdep_assert_held(&led_cdev->led_access); 317 318 led_cdev->flags |= LED_SYSFS_DISABLE; 319 } 320 EXPORT_SYMBOL_GPL(led_sysfs_disable); 321 322 /* Caller must ensure led_cdev->led_access held */ 323 void led_sysfs_enable(struct led_classdev *led_cdev) 324 { 325 lockdep_assert_held(&led_cdev->led_access); 326 327 led_cdev->flags &= ~LED_SYSFS_DISABLE; 328 } 329 EXPORT_SYMBOL_GPL(led_sysfs_enable); 330