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, unsigned int value) 43 { 44 if (!led_cdev->brightness_set) 45 return -ENOTSUPP; 46 47 led_cdev->brightness_set(led_cdev, value); 48 49 return 0; 50 } 51 52 static int __led_set_brightness_blocking(struct led_classdev *led_cdev, unsigned int value) 53 { 54 if (!led_cdev->brightness_set_blocking) 55 return -ENOTSUPP; 56 57 return led_cdev->brightness_set_blocking(led_cdev, value); 58 } 59 60 static void led_timer_function(struct timer_list *t) 61 { 62 struct led_classdev *led_cdev = from_timer(led_cdev, t, blink_timer); 63 unsigned long brightness; 64 unsigned long delay; 65 66 if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) { 67 led_set_brightness_nosleep(led_cdev, LED_OFF); 68 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 69 return; 70 } 71 72 if (test_and_clear_bit(LED_BLINK_ONESHOT_STOP, 73 &led_cdev->work_flags)) { 74 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 75 return; 76 } 77 78 brightness = led_get_brightness(led_cdev); 79 if (!brightness) { 80 /* Time to switch the LED on. */ 81 if (test_and_clear_bit(LED_BLINK_BRIGHTNESS_CHANGE, 82 &led_cdev->work_flags)) 83 brightness = led_cdev->new_blink_brightness; 84 else 85 brightness = led_cdev->blink_brightness; 86 delay = led_cdev->blink_delay_on; 87 } else { 88 /* Store the current brightness value to be able 89 * to restore it when the delay_off period is over. 90 */ 91 led_cdev->blink_brightness = brightness; 92 brightness = LED_OFF; 93 delay = led_cdev->blink_delay_off; 94 } 95 96 led_set_brightness_nosleep(led_cdev, brightness); 97 98 /* Return in next iteration if led is in one-shot mode and we are in 99 * the final blink state so that the led is toggled each delay_on + 100 * delay_off milliseconds in worst case. 101 */ 102 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags)) { 103 if (test_bit(LED_BLINK_INVERT, &led_cdev->work_flags)) { 104 if (brightness) 105 set_bit(LED_BLINK_ONESHOT_STOP, 106 &led_cdev->work_flags); 107 } else { 108 if (!brightness) 109 set_bit(LED_BLINK_ONESHOT_STOP, 110 &led_cdev->work_flags); 111 } 112 } 113 114 mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); 115 } 116 117 static void set_brightness_delayed(struct work_struct *ws) 118 { 119 struct led_classdev *led_cdev = 120 container_of(ws, struct led_classdev, set_brightness_work); 121 int ret = 0; 122 123 if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { 124 led_cdev->delayed_set_value = LED_OFF; 125 led_stop_software_blink(led_cdev); 126 } 127 128 ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value); 129 if (ret == -ENOTSUPP) 130 ret = __led_set_brightness_blocking(led_cdev, 131 led_cdev->delayed_set_value); 132 if (ret < 0 && 133 /* LED HW might have been unplugged, therefore don't warn */ 134 !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && 135 (led_cdev->flags & LED_HW_PLUGGABLE))) 136 dev_err(led_cdev->dev, 137 "Setting an LED's brightness failed (%d)\n", ret); 138 } 139 140 static void led_set_software_blink(struct led_classdev *led_cdev, 141 unsigned long delay_on, 142 unsigned long delay_off) 143 { 144 int current_brightness; 145 146 current_brightness = led_get_brightness(led_cdev); 147 if (current_brightness) 148 led_cdev->blink_brightness = current_brightness; 149 if (!led_cdev->blink_brightness) 150 led_cdev->blink_brightness = led_cdev->max_brightness; 151 152 led_cdev->blink_delay_on = delay_on; 153 led_cdev->blink_delay_off = delay_off; 154 155 /* never on - just set to off */ 156 if (!delay_on) { 157 led_set_brightness_nosleep(led_cdev, LED_OFF); 158 return; 159 } 160 161 /* never off - just set to brightness */ 162 if (!delay_off) { 163 led_set_brightness_nosleep(led_cdev, 164 led_cdev->blink_brightness); 165 return; 166 } 167 168 set_bit(LED_BLINK_SW, &led_cdev->work_flags); 169 mod_timer(&led_cdev->blink_timer, jiffies + 1); 170 } 171 172 173 static void led_blink_setup(struct led_classdev *led_cdev, 174 unsigned long *delay_on, 175 unsigned long *delay_off) 176 { 177 if (!test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 178 led_cdev->blink_set && 179 !led_cdev->blink_set(led_cdev, delay_on, delay_off)) 180 return; 181 182 /* blink with 1 Hz as default if nothing specified */ 183 if (!*delay_on && !*delay_off) 184 *delay_on = *delay_off = 500; 185 186 led_set_software_blink(led_cdev, *delay_on, *delay_off); 187 } 188 189 void led_init_core(struct led_classdev *led_cdev) 190 { 191 INIT_WORK(&led_cdev->set_brightness_work, set_brightness_delayed); 192 193 timer_setup(&led_cdev->blink_timer, led_timer_function, 0); 194 } 195 EXPORT_SYMBOL_GPL(led_init_core); 196 197 void led_blink_set(struct led_classdev *led_cdev, 198 unsigned long *delay_on, 199 unsigned long *delay_off) 200 { 201 del_timer_sync(&led_cdev->blink_timer); 202 203 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 204 clear_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 205 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 206 207 led_blink_setup(led_cdev, delay_on, delay_off); 208 } 209 EXPORT_SYMBOL_GPL(led_blink_set); 210 211 void led_blink_set_oneshot(struct led_classdev *led_cdev, 212 unsigned long *delay_on, 213 unsigned long *delay_off, 214 int invert) 215 { 216 if (test_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags) && 217 timer_pending(&led_cdev->blink_timer)) 218 return; 219 220 set_bit(LED_BLINK_ONESHOT, &led_cdev->work_flags); 221 clear_bit(LED_BLINK_ONESHOT_STOP, &led_cdev->work_flags); 222 223 if (invert) 224 set_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 225 else 226 clear_bit(LED_BLINK_INVERT, &led_cdev->work_flags); 227 228 led_blink_setup(led_cdev, delay_on, delay_off); 229 } 230 EXPORT_SYMBOL_GPL(led_blink_set_oneshot); 231 232 void led_stop_software_blink(struct led_classdev *led_cdev) 233 { 234 del_timer_sync(&led_cdev->blink_timer); 235 led_cdev->blink_delay_on = 0; 236 led_cdev->blink_delay_off = 0; 237 clear_bit(LED_BLINK_SW, &led_cdev->work_flags); 238 } 239 EXPORT_SYMBOL_GPL(led_stop_software_blink); 240 241 void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness) 242 { 243 /* 244 * If software blink is active, delay brightness setting 245 * until the next timer tick. 246 */ 247 if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { 248 /* 249 * If we need to disable soft blinking delegate this to the 250 * work queue task to avoid problems in case we are called 251 * from hard irq context. 252 */ 253 if (!brightness) { 254 set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); 255 schedule_work(&led_cdev->set_brightness_work); 256 } else { 257 set_bit(LED_BLINK_BRIGHTNESS_CHANGE, 258 &led_cdev->work_flags); 259 led_cdev->new_blink_brightness = brightness; 260 } 261 return; 262 } 263 264 led_set_brightness_nosleep(led_cdev, brightness); 265 } 266 EXPORT_SYMBOL_GPL(led_set_brightness); 267 268 void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value) 269 { 270 /* Use brightness_set op if available, it is guaranteed not to sleep */ 271 if (!__led_set_brightness(led_cdev, value)) 272 return; 273 274 /* If brightness setting can sleep, delegate it to a work queue task */ 275 led_cdev->delayed_set_value = value; 276 schedule_work(&led_cdev->set_brightness_work); 277 } 278 EXPORT_SYMBOL_GPL(led_set_brightness_nopm); 279 280 void led_set_brightness_nosleep(struct led_classdev *led_cdev, unsigned int value) 281 { 282 led_cdev->brightness = min(value, led_cdev->max_brightness); 283 284 if (led_cdev->flags & LED_SUSPENDED) 285 return; 286 287 led_set_brightness_nopm(led_cdev, led_cdev->brightness); 288 } 289 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep); 290 291 int led_set_brightness_sync(struct led_classdev *led_cdev, unsigned int value) 292 { 293 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off) 294 return -EBUSY; 295 296 led_cdev->brightness = min(value, led_cdev->max_brightness); 297 298 if (led_cdev->flags & LED_SUSPENDED) 299 return 0; 300 301 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness); 302 } 303 EXPORT_SYMBOL_GPL(led_set_brightness_sync); 304 305 int led_update_brightness(struct led_classdev *led_cdev) 306 { 307 int ret = 0; 308 309 if (led_cdev->brightness_get) { 310 ret = led_cdev->brightness_get(led_cdev); 311 if (ret >= 0) { 312 led_cdev->brightness = ret; 313 return 0; 314 } 315 } 316 317 return ret; 318 } 319 EXPORT_SYMBOL_GPL(led_update_brightness); 320 321 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size) 322 { 323 struct fwnode_handle *fwnode = led_cdev->dev->fwnode; 324 u32 *pattern; 325 int count; 326 327 count = fwnode_property_count_u32(fwnode, "led-pattern"); 328 if (count < 0) 329 return NULL; 330 331 pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL); 332 if (!pattern) 333 return NULL; 334 335 if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) { 336 kfree(pattern); 337 return NULL; 338 } 339 340 *size = count; 341 342 return pattern; 343 } 344 EXPORT_SYMBOL_GPL(led_get_default_pattern); 345 346 /* Caller must ensure led_cdev->led_access held */ 347 void led_sysfs_disable(struct led_classdev *led_cdev) 348 { 349 lockdep_assert_held(&led_cdev->led_access); 350 351 led_cdev->flags |= LED_SYSFS_DISABLE; 352 } 353 EXPORT_SYMBOL_GPL(led_sysfs_disable); 354 355 /* Caller must ensure led_cdev->led_access held */ 356 void led_sysfs_enable(struct led_classdev *led_cdev) 357 { 358 lockdep_assert_held(&led_cdev->led_access); 359 360 led_cdev->flags &= ~LED_SYSFS_DISABLE; 361 } 362 EXPORT_SYMBOL_GPL(led_sysfs_enable); 363 364 static void led_parse_fwnode_props(struct device *dev, 365 struct fwnode_handle *fwnode, 366 struct led_properties *props) 367 { 368 int ret; 369 370 if (!fwnode) 371 return; 372 373 if (fwnode_property_present(fwnode, "label")) { 374 ret = fwnode_property_read_string(fwnode, "label", &props->label); 375 if (ret) 376 dev_err(dev, "Error parsing 'label' property (%d)\n", ret); 377 return; 378 } 379 380 if (fwnode_property_present(fwnode, "color")) { 381 ret = fwnode_property_read_u32(fwnode, "color", &props->color); 382 if (ret) 383 dev_err(dev, "Error parsing 'color' property (%d)\n", ret); 384 else if (props->color >= LED_COLOR_ID_MAX) 385 dev_err(dev, "LED color identifier out of range\n"); 386 else 387 props->color_present = true; 388 } 389 390 391 if (!fwnode_property_present(fwnode, "function")) 392 return; 393 394 ret = fwnode_property_read_string(fwnode, "function", &props->function); 395 if (ret) { 396 dev_err(dev, 397 "Error parsing 'function' property (%d)\n", 398 ret); 399 } 400 401 if (!fwnode_property_present(fwnode, "function-enumerator")) 402 return; 403 404 ret = fwnode_property_read_u32(fwnode, "function-enumerator", 405 &props->func_enum); 406 if (ret) { 407 dev_err(dev, 408 "Error parsing 'function-enumerator' property (%d)\n", 409 ret); 410 } else { 411 props->func_enum_present = true; 412 } 413 } 414 415 int led_compose_name(struct device *dev, struct led_init_data *init_data, 416 char *led_classdev_name) 417 { 418 struct led_properties props = {}; 419 struct fwnode_handle *fwnode = init_data->fwnode; 420 const char *devicename = init_data->devicename; 421 422 /* We want to label LEDs that can produce full range of colors 423 * as RGB, not multicolor */ 424 BUG_ON(props.color == LED_COLOR_ID_MULTI); 425 426 if (!led_classdev_name) 427 return -EINVAL; 428 429 led_parse_fwnode_props(dev, fwnode, &props); 430 431 if (props.label) { 432 /* 433 * If init_data.devicename is NULL, then it indicates that 434 * DT label should be used as-is for LED class device name. 435 * Otherwise the label is prepended with devicename to compose 436 * the final LED class device name. 437 */ 438 if (!devicename) { 439 strscpy(led_classdev_name, props.label, 440 LED_MAX_NAME_SIZE); 441 } else { 442 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 443 devicename, props.label); 444 } 445 } else if (props.function || props.color_present) { 446 char tmp_buf[LED_MAX_NAME_SIZE]; 447 448 if (props.func_enum_present) { 449 snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s-%d", 450 props.color_present ? led_colors[props.color] : "", 451 props.function ?: "", props.func_enum); 452 } else { 453 snprintf(tmp_buf, LED_MAX_NAME_SIZE, "%s:%s", 454 props.color_present ? led_colors[props.color] : "", 455 props.function ?: ""); 456 } 457 if (init_data->devname_mandatory) { 458 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 459 devicename, tmp_buf); 460 } else { 461 strscpy(led_classdev_name, tmp_buf, LED_MAX_NAME_SIZE); 462 463 } 464 } else if (init_data->default_label) { 465 if (!devicename) { 466 dev_err(dev, "Legacy LED naming requires devicename segment"); 467 return -EINVAL; 468 } 469 snprintf(led_classdev_name, LED_MAX_NAME_SIZE, "%s:%s", 470 devicename, init_data->default_label); 471 } else if (is_of_node(fwnode)) { 472 strscpy(led_classdev_name, to_of_node(fwnode)->name, 473 LED_MAX_NAME_SIZE); 474 } else 475 return -EINVAL; 476 477 return 0; 478 } 479 EXPORT_SYMBOL_GPL(led_compose_name); 480