drivers/leds/led-core.c

   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/of.h>
  20 #include <linux/rwsem.h>
  21 #include <linux/slab.h>
  22 #include "leds.h"
  23
  24 DECLARE_RWSEM(leds_list_lock);
  25 EXPORT_SYMBOL_GPL(leds_list_lock);
  26
  27 LIST_HEAD(leds_list);
  28 EXPORT_SYMBOL_GPL(leds_list);
  29
  30 static int __led_set_brightness(struct led_classdev *led_cdev,
  31                                 enum led_brightness value)
  32 {
  33         if (!led_cdev->brightness_set)
  34                 return -ENOTSUPP;
  35
  36         led_cdev->brightness_set(led_cdev, value);
  37
  38         return 0;
  39 }
  40
  41 static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
  42                                          enum led_brightness value)
  43 {
  44         if (!led_cdev->brightness_set_blocking)
  45                 return -ENOTSUPP;
  46
  47         return led_cdev->brightness_set_blocking(led_cdev, value);
  48 }
  49
  50 static void led_timer_function(struct timer_list *t)
  51 {
  52         struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer);
  53         unsigned long brightness;
  54         unsigned long delay;
  55
  56         if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
  57                 led_set_brightness_nosleep(led_cdev, LED_OFF);
  58                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  59                 return;
  60         }
  61
  62         if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP,
  63                                &led_cdev->work_flags)) {
  64                 clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
  65                 return;
  66         }
  67
  68         brightness = led_get_brightness(led_cdev);
  69         if (!brightness) {
  70                 /* Time to switch the LED on. */
  71                 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE,
  72                                         &led_cdev->work_flags))
  73                         brightness = led_cdev->new_blink_brightness;
  74                 else
  75                         brightness = led_cdev->blink_brightness;
  76                 delay = led_cdev->blink_delay_on;
  77         } else {
  78                 /* Store the current brightness value to be able
  79                  * to restore it when the delay_off period is over.
  80                  */
  81                 led_cdev->blink_brightness = brightness;
  82                 brightness = LED_OFF;
  83                 delay = led_cdev->blink_delay_off;
  84         }
  85
  86         led_set_brightness_nosleep(led_cdev, brightness);
  87
  88         /* Return in next iteration if led is in one-shot mode and we are in
  89          * the final blink state so that the led is toggled each delay_on +
  90          * delay_off milliseconds in worst case.
  91          */
  92         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) {
  93                 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) {
  94                         if (brightness)
  95                                 set_bit(LED_BLINK_ONESHOT_STOP,
  96                                         &led_cdev->work_flags);
  97                 } else {
  98                         if (!brightness)
  99                                 set_bit(LED_BLINK_ONESHOT_STOP,
 100                                         &led_cdev->work_flags);
 101                 }
 102         }
 103
 104         mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
 105 }
 106
 107 static void set_brightness_delayed(struct work_struct *ws)
 108 {
 109         struct led_classdev *led_cdev =
 110                 container_of(ws, struct led_classdev, set_brightness_work);
 111         int ret = 0;
 112
 113         if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) {
 114                 led_cdev->delayed_set_value = LED_OFF;
 115                 led_stop_software_blink(led_cdev);
 116         }
 117
 118         ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value);
 119         if (ret == -ENOTSUPP)
 120                 ret = __led_set_brightness_blocking(led_cdev,
 121                                         led_cdev->delayed_set_value);
 122         if (ret < 0 &&
 123             /* LED HW might have been unplugged, therefore don't warn */
 124             !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
 125             (led_cdev->flags & LED_HW_PLUGGABLE)))
 126                 dev_err(led_cdev->dev,
 127                         "Setting an LED's brightness failed (%d)\n", ret);
 128 }
 129
 130 static void led_set_software_blink(struct led_classdev *led_cdev,
 131                                    unsigned long delay_on,
 132                                    unsigned long delay_off)
 133 {
 134         int current_brightness;
 135
 136         current_brightness = led_get_brightness(led_cdev);
 137         if (current_brightness)
 138                 led_cdev->blink_brightness = current_brightness;
 139         if (!led_cdev->blink_brightness)
 140                 led_cdev->blink_brightness = led_cdev->max_brightness;
 141
 142         led_cdev->blink_delay_on = delay_on;
 143         led_cdev->blink_delay_off = delay_off;
 144
 145         /* never on - just set to off */
 146         if (!delay_on) {
 147                 led_set_brightness_nosleep(led_cdev, LED_OFF);
 148                 return;
 149         }
 150
 151         /* never off - just set to brightness */
 152         if (!delay_off) {
 153                 led_set_brightness_nosleep(led_cdev,
 154                                            led_cdev->blink_brightness);
 155                 return;
 156         }
 157
 158         set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 159         mod_timer(&led_cdev->blink_timer, jiffies + 1);
 160 }
 161
 162
 163 static void led_blink_setup(struct led_classdev *led_cdev,
 164                      unsigned long *delay_on,
 165                      unsigned long *delay_off)
 166 {
 167         if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 168             led_cdev->blink_set &&
 169             !led_cdev->blink_set(led_cdev, delay_on, delay_off))
 170                 return;
 171
 172         /* blink with 1 Hz as default if nothing specified */
 173         if (!*delay_on && !*delay_off)
 174                 *delay_on = *delay_off = 500;
 175
 176         led_set_software_blink(led_cdev, *delay_on, *delay_off);
 177 }
 178
 179 void led_init_core(struct led_classdev *led_cdev)
 180 {
 181         INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed);
 182
 183         timer_setup(&led_cdev->blink_timer, led_timer_function, 0);
 184 }
 185 EXPORT_SYMBOL_GPL(led_init_core);
 186
 187 void led_blink_set(struct led_classdev *led_cdev,
 188                    unsigned long *delay_on,
 189                    unsigned long *delay_off)
 190 {
 191         del_timer_sync(&led_cdev->blink_timer);
 192
 193         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 194         clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 195         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 196
 197         led_blink_setup(led_cdev, delay_on, delay_off);
 198 }
 199 EXPORT_SYMBOL_GPL(led_blink_set);
 200
 201 void led_blink_set_oneshot(struct led_classdev *led_cdev,
 202                            unsigned long *delay_on,
 203                            unsigned long *delay_off,
 204                            int invert)
 205 {
 206         if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) &&
 207              timer_pending(&led_cdev->blink_timer))
 208                 return;
 209
 210         set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags);
 211         clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags);
 212
 213         if (invert)
 214                 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 215         else
 216                 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags);
 217
 218         led_blink_setup(led_cdev, delay_on, delay_off);
 219 }
 220 EXPORT_SYMBOL_GPL(led_blink_set_oneshot);
 221
 222 void led_stop_software_blink(struct led_classdev *led_cdev)
 223 {
 224         del_timer_sync(&led_cdev->blink_timer);
 225         led_cdev->blink_delay_on = 0;
 226         led_cdev->blink_delay_off = 0;
 227         clear_bit(LED_BLINK_SW, &led_cdev->work_flags);
 228 }
 229 EXPORT_SYMBOL_GPL(led_stop_software_blink);
 230
 231 void led_set_brightness(struct led_classdev *led_cdev,
 232                         enum led_brightness brightness)
 233 {
 234         /*
 235          * If software blink is active, delay brightness setting
 236          * until the next timer tick.
 237          */
 238         if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
 239                 /*
 240                  * If we need to disable soft blinking delegate this to the
 241                  * work queue task to avoid problems in case we are called
 242                  * from hard irq context.
 243                  */
 244                 if (brightness == LED_OFF) {
 245                         set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
 246                         schedule_work(&led_cdev->set_brightness_work);
 247                 } else {
 248                         set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
 249                                 &led_cdev->work_flags);
 250                         led_cdev->new_blink_brightness = brightness;
 251                 }
 252                 return;
 253         }
 254
 255         led_set_brightness_nosleep(led_cdev, brightness);
 256 }
 257 EXPORT_SYMBOL_GPL(led_set_brightness);
 258
 259 void led_set_brightness_nopm(struct led_classdev *led_cdev,
 260                               enum led_brightness value)
 261 {
 262         /* Use brightness_set op if available, it is guaranteed not to sleep */
 263         if (!__led_set_brightness(led_cdev, value))
 264                 return;
 265
 266         /* If brightness setting can sleep, delegate it to a work queue task */
 267         led_cdev->delayed_set_value = value;
 268         schedule_work(&led_cdev->set_brightness_work);
 269 }
 270 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
 271
 272 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
 273                                 enum led_brightness value)
 274 {
 275         led_cdev->brightness = min(value, led_cdev->max_brightness);
 276
 277         if (led_cdev->flags & LED_SUSPENDED)
 278                 return;
 279
 280         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 281 }
 282 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
 283
 284 int led_set_brightness_sync(struct led_classdev *led_cdev,
 285                             enum led_brightness value)
 286 {
 287         if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
 288                 return -EBUSY;
 289
 290         led_cdev->brightness = min(value, led_cdev->max_brightness);
 291
 292         if (led_cdev->flags & LED_SUSPENDED)
 293                 return 0;
 294
 295         return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
 296 }
 297 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
 298
 299 int led_update_brightness(struct led_classdev *led_cdev)
 300 {
 301         int ret = 0;
 302
 303         if (led_cdev->brightness_get) {
 304                 ret = led_cdev->brightness_get(led_cdev);
 305                 if (ret >= 0) {
 306                         led_cdev->brightness = ret;
 307                         return 0;
 308                 }
 309         }
 310
 311         return ret;
 312 }
 313 EXPORT_SYMBOL_GPL(led_update_brightness);
 314
 315 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
 316 {
 317         struct device_node *np = dev_of_node(led_cdev->dev);
 318         u32 *pattern;
 319         int count;
 320
 321         if (!np)
 322                 return NULL;
 323
 324         count = of_property_count_u32_elems(np, "led-pattern");
 325         if (count < 0)
 326                 return NULL;
 327
 328         pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
 329         if (!pattern)
 330                 return NULL;
 331
 332         if (of_property_read_u32_array(np, "led-pattern", pattern, count)) {
 333                 kfree(pattern);
 334                 return NULL;
 335         }
 336
 337         *size = count;
 338
 339         return pattern;
 340 }
 341 EXPORT_SYMBOL_GPL(led_get_default_pattern);
 342
 343 /* Caller must ensure led_cdev->led_access held */
 344 void led_sysfs_disable(struct led_classdev *led_cdev)
 345 {
 346         lockdep_assert_held(&led_cdev->led_access);
 347
 348         led_cdev->flags |= LED_SYSFS_DISABLE;
 349 }
 350 EXPORT_SYMBOL_GPL(led_sysfs_disable);
 351
 352 /* Caller must ensure led_cdev->led_access held */
 353 void led_sysfs_enable(struct led_classdev *led_cdev)
 354 {
 355         lockdep_assert_held(&led_cdev->led_access);
 356
 357         led_cdev->flags &= ~LED_SYSFS_DISABLE;
 358 }
 359 EXPORT_SYMBOL_GPL(led_sysfs_enable);