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 };
38 EXPORT_SYMBOL_GPL(led_colors);
39
__led_set_brightness(struct led_classdev * led_cdev,enum led_brightness value)40 static int __led_set_brightness(struct led_classdev *led_cdev,
41 enum led_brightness value)
42 {
43 if (!led_cdev->brightness_set)
44 return -ENOTSUPP;
45
46 led_cdev->brightness_set(led_cdev, value);
47
48 return 0;
49 }
50
__led_set_brightness_blocking(struct led_classdev * led_cdev,enum led_brightness value)51 static int __led_set_brightness_blocking(struct led_classdev *led_cdev,
52 enum led_brightness 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
led_timer_function(struct timer_list * t)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
set_brightness_delayed(struct work_struct * ws)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
led_set_software_blink(struct led_classdev * led_cdev,unsigned long delay_on,unsigned long delay_off)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
led_blink_setup(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)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
led_init_core(struct led_classdev * led_cdev)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
led_blink_set(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)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
led_blink_set_oneshot(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off,int invert)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
led_stop_software_blink(struct led_classdev * led_cdev)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
led_set_brightness(struct led_classdev * led_cdev,enum led_brightness brightness)241 void led_set_brightness(struct led_classdev *led_cdev,
242 enum led_brightness brightness)
243 {
244 /*
245 * If software blink is active, delay brightness setting
246 * until the next timer tick.
247 */
248 if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) {
249 /*
250 * If we need to disable soft blinking delegate this to the
251 * work queue task to avoid problems in case we are called
252 * from hard irq context.
253 */
254 if (brightness == LED_OFF) {
255 set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags);
256 schedule_work(&led_cdev->set_brightness_work);
257 } else {
258 set_bit(LED_BLINK_BRIGHTNESS_CHANGE,
259 &led_cdev->work_flags);
260 led_cdev->new_blink_brightness = brightness;
261 }
262 return;
263 }
264
265 led_set_brightness_nosleep(led_cdev, brightness);
266 }
267 EXPORT_SYMBOL_GPL(led_set_brightness);
268
led_set_brightness_nopm(struct led_classdev * led_cdev,enum led_brightness value)269 void led_set_brightness_nopm(struct led_classdev *led_cdev,
270 enum led_brightness value)
271 {
272 /* Use brightness_set op if available, it is guaranteed not to sleep */
273 if (!__led_set_brightness(led_cdev, value))
274 return;
275
276 /* If brightness setting can sleep, delegate it to a work queue task */
277 led_cdev->delayed_set_value = value;
278 schedule_work(&led_cdev->set_brightness_work);
279 }
280 EXPORT_SYMBOL_GPL(led_set_brightness_nopm);
281
led_set_brightness_nosleep(struct led_classdev * led_cdev,enum led_brightness value)282 void led_set_brightness_nosleep(struct led_classdev *led_cdev,
283 enum led_brightness value)
284 {
285 led_cdev->brightness = min(value, led_cdev->max_brightness);
286
287 if (led_cdev->flags & LED_SUSPENDED)
288 return;
289
290 led_set_brightness_nopm(led_cdev, led_cdev->brightness);
291 }
292 EXPORT_SYMBOL_GPL(led_set_brightness_nosleep);
293
led_set_brightness_sync(struct led_classdev * led_cdev,enum led_brightness value)294 int led_set_brightness_sync(struct led_classdev *led_cdev,
295 enum led_brightness value)
296 {
297 if (led_cdev->blink_delay_on || led_cdev->blink_delay_off)
298 return -EBUSY;
299
300 led_cdev->brightness = min(value, led_cdev->max_brightness);
301
302 if (led_cdev->flags & LED_SUSPENDED)
303 return 0;
304
305 return __led_set_brightness_blocking(led_cdev, led_cdev->brightness);
306 }
307 EXPORT_SYMBOL_GPL(led_set_brightness_sync);
308
led_update_brightness(struct led_classdev * led_cdev)309 int led_update_brightness(struct led_classdev *led_cdev)
310 {
311 int ret = 0;
312
313 if (led_cdev->brightness_get) {
314 ret = led_cdev->brightness_get(led_cdev);
315 if (ret >= 0) {
316 led_cdev->brightness = ret;
317 return 0;
318 }
319 }
320
321 return ret;
322 }
323 EXPORT_SYMBOL_GPL(led_update_brightness);
324
led_get_default_pattern(struct led_classdev * led_cdev,unsigned int * size)325 u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
326 {
327 struct fwnode_handle *fwnode = led_cdev->dev->fwnode;
328 u32 *pattern;
329 int count;
330
331 count = fwnode_property_count_u32(fwnode, "led-pattern");
332 if (count < 0)
333 return NULL;
334
335 pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
336 if (!pattern)
337 return NULL;
338
339 if (fwnode_property_read_u32_array(fwnode, "led-pattern", pattern, count)) {
340 kfree(pattern);
341 return NULL;
342 }
343
344 *size = count;
345
346 return pattern;
347 }
348 EXPORT_SYMBOL_GPL(led_get_default_pattern);
349
350 /* Caller must ensure led_cdev->led_access held */
led_sysfs_disable(struct led_classdev * led_cdev)351 void led_sysfs_disable(struct led_classdev *led_cdev)
352 {
353 lockdep_assert_held(&led_cdev->led_access);
354
355 led_cdev->flags |= LED_SYSFS_DISABLE;
356 }
357 EXPORT_SYMBOL_GPL(led_sysfs_disable);
358
359 /* Caller must ensure led_cdev->led_access held */
led_sysfs_enable(struct led_classdev * led_cdev)360 void led_sysfs_enable(struct led_classdev *led_cdev)
361 {
362 lockdep_assert_held(&led_cdev->led_access);
363
364 led_cdev->flags &= ~LED_SYSFS_DISABLE;
365 }
366 EXPORT_SYMBOL_GPL(led_sysfs_enable);
367
led_parse_fwnode_props(struct device * dev,struct fwnode_handle * fwnode,struct led_properties * props)368 static void led_parse_fwnode_props(struct device *dev,
369 struct fwnode_handle *fwnode,
370 struct led_properties *props)
371 {
372 int ret;
373
374 if (!fwnode)
375 return;
376
377 if (fwnode_property_present(fwnode, "label")) {
378 ret = fwnode_property_read_string(fwnode, "label", &props->label);
379 if (ret)
380 dev_err(dev, "Error parsing 'label' property (%d)\n", ret);
381 return;
382 }
383
384 if (fwnode_property_present(fwnode, "color")) {
385 ret = fwnode_property_read_u32(fwnode, "color", &props->color);
386 if (ret)
387 dev_err(dev, "Error parsing 'color' property (%d)\n", ret);
388 else if (props->color >= LED_COLOR_ID_MAX)
389 dev_err(dev, "LED color identifier out of range\n");
390 else
391 props->color_present = true;
392 }
393
394
395 if (!fwnode_property_present(fwnode, "function"))
396 return;
397
398 ret = fwnode_property_read_string(fwnode, "function", &props->function);
399 if (ret) {
400 dev_err(dev,
401 "Error parsing 'function' property (%d)\n",
402 ret);
403 }
404
405 if (!fwnode_property_present(fwnode, "function-enumerator"))
406 return;
407
408 ret = fwnode_property_read_u32(fwnode, "function-enumerator",
409 &props->func_enum);
410 if (ret) {
411 dev_err(dev,
412 "Error parsing 'function-enumerator' property (%d)\n",
413 ret);
414 } else {
415 props->func_enum_present = true;
416 }
417 }
418
led_compose_name(struct device * dev,struct led_init_data * init_data,char * led_classdev_name)419 int led_compose_name(struct device *dev, struct led_init_data *init_data,
420 char *led_classdev_name)
421 {
422 struct led_properties props = {};
423 struct fwnode_handle *fwnode = init_data->fwnode;
424 const char *devicename = init_data->devicename;
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