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