1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LED Class Core 4 * 5 * Copyright 2005-2006 Openedhand Ltd. 6 * 7 * Author: Richard Purdie <rpurdie@openedhand.com> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/leds.h> 12 #include <linux/list.h> 13 #include <linux/module.h> 14 #include <linux/mutex.h> 15 #include <linux/of.h> 16 #include <linux/property.h> 17 #include <linux/rwsem.h> 18 #include <linux/slab.h> 19 #include <uapi/linux/uleds.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 const char * const led_colors[LED_COLOR_ID_MAX] = { 29 [LED_COLOR_ID_WHITE] = "white", 30 [LED_COLOR_ID_RED] = "red", 31 [LED_COLOR_ID_GREEN] = "green", 32 [LED_COLOR_ID_BLUE] = "blue", 33 [LED_COLOR_ID_AMBER] = "amber", 34 [LED_COLOR_ID_VIOLET] = "violet", 35 [LED_COLOR_ID_YELLOW] = "yellow", 36 [LED_COLOR_ID_IR] = "ir", 37 [LED_COLOR_ID_MULTI] = "multicolor", 38 [LED_COLOR_ID_RGB] = "rgb", 39 }; 40 EXPORT_SYMBOL_GPL(led_colors); 41 42 static int __led_set_brightness(struct led_classdev *led_cdev, 43 enum led_brightness value) 44 { 45 if (!led_cdev->brightness_set) 46 return -ENOTSUPP; 47 48 led_cdev->brightness_set(led_cdev, value); 49 50 return 0; 51 } 52 53 static int __led_set_brightness_blocking(struct led_classdev *led_cdev, 54 enum led_brightness value) 55 { 56 if (!led_cdev->brightness_set_blocking) 57 return -ENOTSUPP; 58 59 return led_cdev->brightness_set_blocking(led_cdev, value); 60 } 61 62 static void led_timer_function(struct timer_list *t) 63 { 64 struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer); 65 unsigned long brightness; 66 unsigned long delay; 67 68 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 69 led_set_brightness_nosleep(led_cdev, LED_OFF); 70 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 71 return; 72 } 73 74 if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP, 75 &led_cdev->work_flags)) { 76 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 77 return; 78 } 79 80 brightness = led_get_brightness(led_cdev); 81 if (!brightness) { 82 /* Time to switch the LED on. */ 83 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, 84 &led_cdev->work_flags)) 85 brightness = led_cdev->new_blink_brightness; 86 else 87 brightness = led_cdev->blink_brightness; 88 delay = led_cdev->blink_delay_on; 89 } else { 90 /* Store the current brightness value to be able 91 * to restore it when the delay_off period is over. 92 */ 93 led_cdev->blink_brightness = brightness; 94 brightness = LED_OFF; 95 delay = led_cdev->blink_delay_off; 96 } 97 98 led_set_brightness_nosleep(led_cdev, brightness); 99 100 /* Return in next iteration if led is in one-shot mode and we are in 101 * the final blink state so that the led is toggled each delay_on + 102 * delay_off milliseconds in worst case. 103 */ 104 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) { 105 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) { 106 if (brightness) 107 set_bit(LED_BLINK_ONESHOT_STOP, 108 &led_cdev->work_flags); 109 } else { 110 if (!brightness) 111 set_bit(LED_BLINK_ONESHOT_STOP, 112 &led_cdev->work_flags); 113 } 114 } 115 116 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 117 } 118 119 static void set_brightness_delayed(struct work_struct *ws) 120 { 121 struct led_classdev *led_cdev = 122 container_of(ws, struct led_classdev, set_brightness_work); 123 int ret = 0; 124 125 if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { 126 led_cdev->delayed_set_value = LED_OFF; 127 led_stop_software_blink(led_cdev); 128 } 129 130 ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 131 if (ret == -ENOTSUPP) 132 ret = __led_set_brightness_blocking(led_cdev, 133 led_cdev->delayed_set_value); 134 if (ret < 0 && 135 /* LED HW might have been unplugged, therefore don't warn */ 136 !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && 137 (led_cdev->flags & LED_HW_PLUGGABLE))) 138 dev_err(led_cdev->dev, 139 "Setting an LED's brightness failed (%d)\n", ret); 140 } 141 142 static void led_set_software_blink(struct led_classdev *led_cdev, 143 unsigned long delay_on, 144 unsigned long delay_off) 145 { 146 int current_brightness; 147 148 current_brightness = led_get_brightness(led_cdev); 149 if (current_brightness) 150 led_cdev->blink_brightness = current_brightness; 151 if (!led_cdev->blink_brightness) 152 led_cdev->blink_brightness = led_cdev->max_brightness; 153 154 led_cdev->blink_delay_on = delay_on; 155 led_cdev->blink_delay_off = delay_off; 156 157 /* never on - just set to off */ 158 if (!delay_on) { 159 led_set_brightness_nosleep(led_cdev, LED_OFF); 160 return; 161 } 162 163 /* never off - just set to brightness */ 164 if (!delay_off) { 165 led_set_brightness_nosleep(led_cdev, 166 led_cdev->blink_brightness); 167 return; 168 } 169 170 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 171 mod_timer(&led_cdev->blink_timer, jiffies + 1); 172 } 173 174 175 static void led_blink_setup(struct led_classdev *led_cdev, 176 unsigned long *delay_on, 177 unsigned long *delay_off) 178 { 179 if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 180 led_cdev->blink_set && 181 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 182 return; 183 184 /* blink with 1 Hz as default if nothing specified */ 185 if (!*delay_on && !*delay_off) 186 *delay_on = *delay_off = 500; 187 188 led_set_software_blink(led_cdev, *delay_on, *delay_off); 189 } 190 191 void led_init_core(struct led_classdev *led_cdev) 192 { 193 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 194 195 timer_setup(&led_cdev->blink_timer, led_timer_function, 0); 196 } 197 EXPORT_SYMBOL_GPL(led_init_core); 198 199 void led_blink_set(struct led_classdev *led_cdev, 200 unsigned long *delay_on, 201 unsigned long *delay_off) 202 { 203 del_timer_sync(&led_cdev->blink_timer); 204 205 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 206 clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 207 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 208 209 led_blink_setup(led_cdev, delay_on, delay_off); 210 } 211 EXPORT_SYMBOL_GPL(led_blink_set); 212 213 void led_blink_set_oneshot(struct led_classdev *led_cdev, 214 unsigned long *delay_on, 215 unsigned long *delay_off, 216 int invert) 217 { 218 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 219 timer_pending(&led_cdev->blink_timer)) 220 return; 221 222 set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 223 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 224 225 if (invert) 226 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 227 else 228 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 229 230 led_blink_setup(led_cdev, delay_on, delay_off); 231 } 232 EXPORT_SYMBOL_GPL(led_blink_set_oneshot); 233 234 void led_stop_software_blink(struct led_classdev *led_cdev) 235 { 236 del_timer_sync(&led_cdev->blink_timer); 237 led_cdev->blink_delay_on = 0; 238 led_cdev->blink_delay_off = 0; 239 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 240 } 241 EXPORT_SYMBOL_GPL(led_stop_software_blink); 242 243 void led_set_brightness(struct led_classdev *led_cdev, 244 enum led_brightness brightness) 245 { 246 /* 247 * If software blink is active, delay brightness setting 248 * until the next timer tick. 249 */ 250 if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { 251 /* 252 * If we need to disable soft blinking delegate this to the 253 * work queue task to avoid problems in case we are called 254 * from hard irq context. 255 */ 256 if (brightness == LED_OFF) { 257 set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); 258 schedule_work(&led_cdev->set_brightness_work); 259 } else { 260 set_bit(LED_BLINK_BRIGHTNESS_CHANGE, 261 &led_cdev->work_flags); 262 led_cdev->new_blink_brightness = brightness; 263 } 264 return; 265 } 266 267 led_set_brightness_nosleep(led_cdev, brightness); 268 } 269 EXPORT_SYMBOL_GPL(led_set_brightness); 270 271 void led_set_brightness_nopm(struct led_classdev *led_cdev, 272 enum led_brightness value) 273 { 274 /* Use brightness_set op if available, it is guaranteed not to sleep */ 275 if (!__led_set_brightness(led_cdev, value)) 276 return; 277 278 /* If brightness setting can sleep, delegate it to a work queue task */ 279 led_cdev->delayed_set_value = value; 280 schedule_work(&led_cdev->set_brightness_work); 281 } 282 EXPORT_SYMBOL_GPL(led_set_brightness_nopm); 283 284 void led_set_brightness_nosleep(struct led_classdev *led_cdev, 285 enum led_brightness value) 286 { 287 led_cdev->brightness = min(value, led_cdev->max_brightness); 288 289 if (led_cdev->flags & LED_SUSPENDED) 290 return; 291 292 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 293 } 294 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); 295 296 int led_set_brightness_sync(struct led_classdev *led_cdev, 297 enum led_brightness value) 298 { 299 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) 300 return -EBUSY; 301 302 led_cdev->brightness = min(value, led_cdev->max_brightness); 303 304 if (led_cdev->flags & LED_SUSPENDED) 305 return 0; 306 307 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness); 308 } 309 EXPORT_SYMBOL_GPL(led_set_brightness_sync); 310 311 int led_update_brightness(struct led_classdev *led_cdev) 312 { 313 int ret = 0; 314 315 if (led_cdev->brightness_get) { 316 ret = led_cdev->brightness_get(led_cdev); 317 if (ret >= 0) { 318 led_cdev->brightness = ret; 319 return 0; 320 } 321 } 322 323 return ret; 324 } 325 EXPORT_SYMBOL_GPL(led_update_brightness); 326 327 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size) 328 { 329 struct fwnode_handle *fwnode = led_cdev->dev->fwnode; 330 u32 *pattern; 331 int count; 332 333 count = fwnode_property_count_u32(fwnode, "led-pattern"); 334 if (count < 0) 335 return NULL; 336 337 pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL); 338 if (!pattern) 339 return NULL; 340 341 if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) { 342 kfree(pattern); 343 return NULL; 344 } 345 346 *size = count; 347 348 return pattern; 349 } 350 EXPORT_SYMBOL_GPL(led_get_default_pattern); 351 352 /* Caller must ensure led_cdev->led_access held */ 353 void led_sysfs_disable(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_disable); 360 361 /* Caller must ensure led_cdev->led_access held */ 362 void led_sysfs_enable(struct led_classdev *led_cdev) 363 { 364 lockdep_assert_held(&led_cdev->led_access); 365 366 led_cdev->flags &= ~LED_SYSFS_DISABLE; 367 } 368 EXPORT_SYMBOL_GPL(led_sysfs_enable); 369 370 static void led_parse_fwnode_props(struct device *dev, 371 struct fwnode_handle *fwnode, 372 struct led_properties *props) 373 { 374 int ret; 375 376 if (!fwnode) 377 return; 378 379 if (fwnode_property_present(fwnode, "label")) { 380 ret = fwnode_property_read_string(fwnode, "label", &props->label); 381 if (ret) 382 dev_err(dev, "Error parsing 'label' property (%d)\n", ret); 383 return; 384 } 385 386 if (fwnode_property_present(fwnode, "color")) { 387 ret = fwnode_property_read_u32(fwnode, "color", &props->color); 388 if (ret) 389 dev_err(dev, "Error parsing 'color' property (%d)\n", ret); 390 else if (props->color >= LED_COLOR_ID_MAX) 391 dev_err(dev, "LED color identifier out of range\n"); 392 else 393 props->color_present = true; 394 } 395 396 397 if (!fwnode_property_present(fwnode, "function")) 398 return; 399 400 ret = fwnode_property_read_string(fwnode, "function", &props->function); 401 if (ret) { 402 dev_err(dev, 403 "Error parsing 'function' property (%d)\n", 404 ret); 405 } 406 407 if (!fwnode_property_present(fwnode, "function-enumerator")) 408 return; 409 410 ret = fwnode_property_read_u32(fwnode, "function-enumerator", 411 &props->func_enum); 412 if (ret) { 413 dev_err(dev, 414 "Error parsing 'function-enumerator' property (%d)\n", 415 ret); 416 } else { 417 props->func_enum_present = true; 418 } 419 } 420 421 int led_compose_name(struct device *dev, struct led_init_data *init_data, 422 char *led_classdev_name) 423 { 424 struct led_properties props = {}; 425 struct fwnode_handle *fwnode = init_data->fwnode; 426 const char *devicename = init_data->devicename; 427 428 /* We want to label LEDs that can produce full range of colors 429 * as RGB, not multicolor */ 430 BUG_ON(props.color == LED_COLOR_ID_MULTI); 431 432 if (!led_classdev_name) 433 return -EINVAL; 434 435 led_parse_fwnode_props(dev, fwnode, &props); 436 437 if (props.label) { 438 /* 439 * If init_data.devicename is NULL, then it indicates that 440 * DT label should be used as-is for LED class device name. 441 * Otherwise the label is prepended with devicename to compose 442 * the final LED class device name. 443 */ 444 if (!devicename) { 445 strscpy(led_classdev_name, props.label, 446 LED_MAX_NAME_SIZE); 447 } else { 448 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 449 devicename, props.label); 450 } 451 } else if (props.function || props.color_present) { 452 char tmp_buf[LED_MAX_NAME_SIZE]; 453 454 if (props.func_enum_present) { 455 snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d", 456 props.color_present ? led_colors[props.color] : "", 457 props.function ?: "", props.func_enum); 458 } else { 459 snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s", 460 props.color_present ? led_colors[props.color] : "", 461 props.function ?: ""); 462 } 463 if (init_data->devname_mandatory) { 464 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 465 devicename, tmp_buf); 466 } else { 467 strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE); 468 469 } 470 } else if (init_data->default_label) { 471 if (!devicename) { 472 dev_err(dev, "Legacy LED naming requires devicename segment"); 473 return -EINVAL; 474 } 475 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 476 devicename, init_data->default_label); 477 } else if (is_of_node(fwnode)) { 478 strscpy(led_classdev_name, to_of_node(fwnode)->name, 479 LED_MAX_NAME_SIZE); 480 } else 481 return -EINVAL; 482 483 return 0; 484 } 485 EXPORT_SYMBOL_GPL(led_compose_name); 486