1 /*
2 * LED Flash class driver for the AAT1290
3 * 1.5A Step-Up Current Regulator for Flash LEDs
4 *
5 * Copyright (C) 2015, Samsung Electronics Co., Ltd.
6 * Author: Jacek Anaszewski <j.anaszewski@samsung.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
11 */
12
13 #include <linux/delay.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/led-class-flash.h>
16 #include <linux/leds.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/of.h>
20 #include <linux/pinctrl/consumer.h>
21 #include <linux/platform_device.h>
22 #include <linux/slab.h>
23 #include <linux/workqueue.h>
24 #include <media/v4l2-flash-led-class.h>
25
26 #define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
27 #define AAT1290_MAX_MM_CURR_PERCENT_0 16
28 #define AAT1290_MAX_MM_CURR_PERCENT_100 1
29
30 #define AAT1290_FLASH_SAFETY_TIMER_ADDR 18
31
32 #define AAT1290_MOVIE_MODE_CONFIG_ADDR 19
33 #define AAT1290_MOVIE_MODE_OFF 1
34 #define AAT1290_MOVIE_MODE_ON 3
35
36 #define AAT1290_MM_CURRENT_RATIO_ADDR 20
37 #define AAT1290_MM_TO_FL_1_92 1
38
39 #define AAT1290_MM_TO_FL_RATIO 1000 / 1920
40 #define AAT1290_MAX_MM_CURRENT(fl_max) (fl_max * AAT1290_MM_TO_FL_RATIO)
41
42 #define AAT1290_LATCH_TIME_MIN_US 500
43 #define AAT1290_LATCH_TIME_MAX_US 1000
44 #define AAT1290_EN_SET_TICK_TIME_US 1
45 #define AAT1290_FLEN_OFF_DELAY_TIME_US 10
46 #define AAT1290_FLASH_TM_NUM_LEVELS 16
47 #define AAT1290_MM_CURRENT_SCALE_SIZE 15
48
49
50 struct aat1290_led_config_data {
51 /* maximum LED current in movie mode */
52 u32 max_mm_current;
53 /* maximum LED current in flash mode */
54 u32 max_flash_current;
55 /* maximum flash timeout */
56 u32 max_flash_tm;
57 /* external strobe capability */
58 bool has_external_strobe;
59 /* max LED brightness level */
60 enum led_brightness max_brightness;
61 };
62
63 struct aat1290_led {
64 /* platform device data */
65 struct platform_device *pdev;
66 /* secures access to the device */
67 struct mutex lock;
68
69 /* corresponding LED Flash class device */
70 struct led_classdev_flash fled_cdev;
71 /* V4L2 Flash device */
72 struct v4l2_flash *v4l2_flash;
73
74 /* FLEN pin */
75 struct gpio_desc *gpio_fl_en;
76 /* EN|SET pin */
77 struct gpio_desc *gpio_en_set;
78 /* movie mode current scale */
79 int *mm_current_scale;
80 /* device mode */
81 bool movie_mode;
82
83 /* brightness cache */
84 unsigned int torch_brightness;
85 /* assures led-triggers compatibility */
86 struct work_struct work_brightness_set;
87 };
88
fled_cdev_to_led(struct led_classdev_flash * fled_cdev)89 static struct aat1290_led *fled_cdev_to_led(
90 struct led_classdev_flash *fled_cdev)
91 {
92 return container_of(fled_cdev, struct aat1290_led, fled_cdev);
93 }
94
aat1290_as2cwire_write(struct aat1290_led * led,int addr,int value)95 static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
96 {
97 int i;
98
99 gpiod_direction_output(led->gpio_fl_en, 0);
100 gpiod_direction_output(led->gpio_en_set, 0);
101
102 udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);
103
104 /* write address */
105 for (i = 0; i < addr; ++i) {
106 udelay(AAT1290_EN_SET_TICK_TIME_US);
107 gpiod_direction_output(led->gpio_en_set, 0);
108 udelay(AAT1290_EN_SET_TICK_TIME_US);
109 gpiod_direction_output(led->gpio_en_set, 1);
110 }
111
112 usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
113
114 /* write data */
115 for (i = 0; i < value; ++i) {
116 udelay(AAT1290_EN_SET_TICK_TIME_US);
117 gpiod_direction_output(led->gpio_en_set, 0);
118 udelay(AAT1290_EN_SET_TICK_TIME_US);
119 gpiod_direction_output(led->gpio_en_set, 1);
120 }
121
122 usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
123 }
124
aat1290_set_flash_safety_timer(struct aat1290_led * led,unsigned int micro_sec)125 static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
126 unsigned int micro_sec)
127 {
128 struct led_classdev_flash *fled_cdev = &led->fled_cdev;
129 struct led_flash_setting *flash_tm = &fled_cdev->timeout;
130 int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
131 (micro_sec / flash_tm->step) + 1;
132
133 aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
134 flash_tm_reg);
135 }
136
aat1290_brightness_set(struct aat1290_led * led,enum led_brightness brightness)137 static void aat1290_brightness_set(struct aat1290_led *led,
138 enum led_brightness brightness)
139 {
140 mutex_lock(&led->lock);
141
142 if (brightness == 0) {
143 gpiod_direction_output(led->gpio_fl_en, 0);
144 gpiod_direction_output(led->gpio_en_set, 0);
145 led->movie_mode = false;
146 } else {
147 if (!led->movie_mode) {
148 aat1290_as2cwire_write(led,
149 AAT1290_MM_CURRENT_RATIO_ADDR,
150 AAT1290_MM_TO_FL_1_92);
151 led->movie_mode = true;
152 }
153
154 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
155 AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
156 aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
157 AAT1290_MOVIE_MODE_ON);
158 }
159
160 mutex_unlock(&led->lock);
161 }
162
163 /* LED subsystem callbacks */
164
aat1290_brightness_set_work(struct work_struct * work)165 static void aat1290_brightness_set_work(struct work_struct *work)
166 {
167 struct aat1290_led *led =
168 container_of(work, struct aat1290_led, work_brightness_set);
169
170 aat1290_brightness_set(led, led->torch_brightness);
171 }
172
aat1290_led_brightness_set(struct led_classdev * led_cdev,enum led_brightness brightness)173 static void aat1290_led_brightness_set(struct led_classdev *led_cdev,
174 enum led_brightness brightness)
175 {
176 struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
177 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
178
179 led->torch_brightness = brightness;
180 schedule_work(&led->work_brightness_set);
181 }
182
aat1290_led_brightness_set_sync(struct led_classdev * led_cdev,enum led_brightness brightness)183 static int aat1290_led_brightness_set_sync(struct led_classdev *led_cdev,
184 enum led_brightness brightness)
185 {
186 struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
187 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
188
189 aat1290_brightness_set(led, brightness);
190
191 return 0;
192 }
193
aat1290_led_flash_strobe_set(struct led_classdev_flash * fled_cdev,bool state)194 static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
195 bool state)
196
197 {
198 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
199 struct led_classdev *led_cdev = &fled_cdev->led_cdev;
200 struct led_flash_setting *timeout = &fled_cdev->timeout;
201
202 mutex_lock(&led->lock);
203
204 if (state) {
205 aat1290_set_flash_safety_timer(led, timeout->val);
206 gpiod_direction_output(led->gpio_fl_en, 1);
207 } else {
208 gpiod_direction_output(led->gpio_fl_en, 0);
209 gpiod_direction_output(led->gpio_en_set, 0);
210 }
211
212 /*
213 * To reenter movie mode after a flash event the part must be cycled
214 * off and back on to reset the movie mode and reprogrammed via the
215 * AS2Cwire. Therefore the brightness and movie_mode properties needs
216 * to be updated here to reflect the actual state.
217 */
218 led_cdev->brightness = 0;
219 led->movie_mode = false;
220
221 mutex_unlock(&led->lock);
222
223 return 0;
224 }
225
aat1290_led_flash_timeout_set(struct led_classdev_flash * fled_cdev,u32 timeout)226 static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
227 u32 timeout)
228 {
229 /*
230 * Don't do anything - flash timeout is cached in the led-class-flash
231 * core and will be applied in the strobe_set op, as writing the
232 * safety timer register spuriously turns the torch mode on.
233 */
234
235 return 0;
236 }
237
aat1290_led_parse_dt(struct aat1290_led * led,struct aat1290_led_config_data * cfg,struct device_node ** sub_node)238 static int aat1290_led_parse_dt(struct aat1290_led *led,
239 struct aat1290_led_config_data *cfg,
240 struct device_node **sub_node)
241 {
242 struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
243 struct device *dev = &led->pdev->dev;
244 struct device_node *child_node;
245 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
246 struct pinctrl *pinctrl;
247 #endif
248 int ret = 0;
249
250 led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
251 if (IS_ERR(led->gpio_fl_en)) {
252 ret = PTR_ERR(led->gpio_fl_en);
253 dev_err(dev, "Unable to claim gpio \"flen\".\n");
254 return ret;
255 }
256
257 led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
258 if (IS_ERR(led->gpio_en_set)) {
259 ret = PTR_ERR(led->gpio_en_set);
260 dev_err(dev, "Unable to claim gpio \"enset\".\n");
261 return ret;
262 }
263
264 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
265 pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
266 if (IS_ERR(pinctrl)) {
267 cfg->has_external_strobe = false;
268 dev_info(dev,
269 "No support for external strobe detected.\n");
270 } else {
271 cfg->has_external_strobe = true;
272 }
273 #endif
274
275 child_node = of_get_next_available_child(dev->of_node, NULL);
276 if (!child_node) {
277 dev_err(dev, "No DT child node found for connected LED.\n");
278 return -EINVAL;
279 }
280
281 led_cdev->name = of_get_property(child_node, "label", NULL) ? :
282 child_node->name;
283
284 ret = of_property_read_u32(child_node, "led-max-microamp",
285 &cfg->max_mm_current);
286 /*
287 * led-max-microamp will default to 1/20 of flash-max-microamp
288 * in case it is missing.
289 */
290 if (ret < 0)
291 dev_warn(dev,
292 "led-max-microamp DT property missing\n");
293
294 ret = of_property_read_u32(child_node, "flash-max-microamp",
295 &cfg->max_flash_current);
296 if (ret < 0) {
297 dev_err(dev,
298 "flash-max-microamp DT property missing\n");
299 return ret;
300 }
301
302 ret = of_property_read_u32(child_node, "flash-max-timeout-us",
303 &cfg->max_flash_tm);
304 if (ret < 0) {
305 dev_err(dev,
306 "flash-max-timeout-us DT property missing\n");
307 return ret;
308 }
309
310 of_node_put(child_node);
311
312 *sub_node = child_node;
313
314 return ret;
315 }
316
aat1290_led_validate_mm_current(struct aat1290_led * led,struct aat1290_led_config_data * cfg)317 static void aat1290_led_validate_mm_current(struct aat1290_led *led,
318 struct aat1290_led_config_data *cfg)
319 {
320 int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
321
322 while (e - b > 1) {
323 i = b + (e - b) / 2;
324 if (cfg->max_mm_current < led->mm_current_scale[i])
325 e = i;
326 else
327 b = i;
328 }
329
330 cfg->max_mm_current = led->mm_current_scale[b];
331 cfg->max_brightness = b + 1;
332 }
333
init_mm_current_scale(struct aat1290_led * led,struct aat1290_led_config_data * cfg)334 static int init_mm_current_scale(struct aat1290_led *led,
335 struct aat1290_led_config_data *cfg)
336 {
337 int max_mm_current_percent[] = { 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
338 63, 71, 79, 89, 100 };
339 int i, max_mm_current =
340 AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
341
342 led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
343 sizeof(max_mm_current_percent),
344 GFP_KERNEL);
345 if (!led->mm_current_scale)
346 return -ENOMEM;
347
348 for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
349 led->mm_current_scale[i] = max_mm_current *
350 max_mm_current_percent[i] / 100;
351
352 return 0;
353 }
354
aat1290_led_get_configuration(struct aat1290_led * led,struct aat1290_led_config_data * cfg,struct device_node ** sub_node)355 static int aat1290_led_get_configuration(struct aat1290_led *led,
356 struct aat1290_led_config_data *cfg,
357 struct device_node **sub_node)
358 {
359 int ret;
360
361 ret = aat1290_led_parse_dt(led, cfg, sub_node);
362 if (ret < 0)
363 return ret;
364 /*
365 * Init non-linear movie mode current scale basing
366 * on the max flash current from led configuration.
367 */
368 ret = init_mm_current_scale(led, cfg);
369 if (ret < 0)
370 return ret;
371
372 aat1290_led_validate_mm_current(led, cfg);
373
374 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
375 #else
376 devm_kfree(&led->pdev->dev, led->mm_current_scale);
377 #endif
378
379 return 0;
380 }
381
aat1290_init_flash_timeout(struct aat1290_led * led,struct aat1290_led_config_data * cfg)382 static void aat1290_init_flash_timeout(struct aat1290_led *led,
383 struct aat1290_led_config_data *cfg)
384 {
385 struct led_classdev_flash *fled_cdev = &led->fled_cdev;
386 struct led_flash_setting *setting;
387
388 /* Init flash timeout setting */
389 setting = &fled_cdev->timeout;
390 setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
391 setting->max = cfg->max_flash_tm;
392 setting->step = setting->min;
393 setting->val = setting->max;
394 }
395
396 #if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
aat1290_intensity_to_brightness(struct v4l2_flash * v4l2_flash,s32 intensity)397 static enum led_brightness aat1290_intensity_to_brightness(
398 struct v4l2_flash *v4l2_flash,
399 s32 intensity)
400 {
401 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
402 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
403 int i;
404
405 for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
406 if (intensity >= led->mm_current_scale[i])
407 return i + 1;
408
409 return 1;
410 }
411
aat1290_brightness_to_intensity(struct v4l2_flash * v4l2_flash,enum led_brightness brightness)412 static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
413 enum led_brightness brightness)
414 {
415 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
416 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
417
418 return led->mm_current_scale[brightness - 1];
419 }
420
aat1290_led_external_strobe_set(struct v4l2_flash * v4l2_flash,bool enable)421 static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
422 bool enable)
423 {
424 struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
425 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
426 struct led_classdev *led_cdev = &fled_cdev->led_cdev;
427 struct pinctrl *pinctrl;
428
429 gpiod_direction_output(led->gpio_fl_en, 0);
430 gpiod_direction_output(led->gpio_en_set, 0);
431
432 led->movie_mode = false;
433 led_cdev->brightness = 0;
434
435 pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
436 enable ? "isp" : "host");
437 if (IS_ERR(pinctrl)) {
438 dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
439 return PTR_ERR(pinctrl);
440 }
441
442 return 0;
443 }
444
aat1290_init_v4l2_flash_config(struct aat1290_led * led,struct aat1290_led_config_data * led_cfg,struct v4l2_flash_config * v4l2_sd_cfg)445 static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
446 struct aat1290_led_config_data *led_cfg,
447 struct v4l2_flash_config *v4l2_sd_cfg)
448 {
449 struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
450 struct led_flash_setting *s;
451
452 strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
453 sizeof(v4l2_sd_cfg->dev_name));
454
455 s = &v4l2_sd_cfg->torch_intensity;
456 s->min = led->mm_current_scale[0];
457 s->max = led_cfg->max_mm_current;
458 s->step = 1;
459 s->val = s->max;
460
461 v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
462 }
463
464 static const struct v4l2_flash_ops v4l2_flash_ops = {
465 .external_strobe_set = aat1290_led_external_strobe_set,
466 .intensity_to_led_brightness = aat1290_intensity_to_brightness,
467 .led_brightness_to_intensity = aat1290_brightness_to_intensity,
468 };
469 #else
aat1290_init_v4l2_flash_config(struct aat1290_led * led,struct aat1290_led_config_data * led_cfg,struct v4l2_flash_config * v4l2_sd_cfg)470 static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
471 struct aat1290_led_config_data *led_cfg,
472 struct v4l2_flash_config *v4l2_sd_cfg)
473 {
474 }
475 static const struct v4l2_flash_ops v4l2_flash_ops;
476 #endif
477
478 static const struct led_flash_ops flash_ops = {
479 .strobe_set = aat1290_led_flash_strobe_set,
480 .timeout_set = aat1290_led_flash_timeout_set,
481 };
482
aat1290_led_probe(struct platform_device * pdev)483 static int aat1290_led_probe(struct platform_device *pdev)
484 {
485 struct device *dev = &pdev->dev;
486 struct device_node *sub_node = NULL;
487 struct aat1290_led *led;
488 struct led_classdev *led_cdev;
489 struct led_classdev_flash *fled_cdev;
490 struct aat1290_led_config_data led_cfg = {};
491 struct v4l2_flash_config v4l2_sd_cfg = {};
492 int ret;
493
494 led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
495 if (!led)
496 return -ENOMEM;
497
498 led->pdev = pdev;
499 platform_set_drvdata(pdev, led);
500
501 fled_cdev = &led->fled_cdev;
502 fled_cdev->ops = &flash_ops;
503 led_cdev = &fled_cdev->led_cdev;
504
505 ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
506 if (ret < 0)
507 return ret;
508
509 mutex_init(&led->lock);
510
511 /* Initialize LED Flash class device */
512 led_cdev->brightness_set = aat1290_led_brightness_set;
513 led_cdev->brightness_set_sync = aat1290_led_brightness_set_sync;
514 led_cdev->max_brightness = led_cfg.max_brightness;
515 led_cdev->flags |= LED_DEV_CAP_FLASH;
516 INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);
517
518 aat1290_init_flash_timeout(led, &led_cfg);
519
520 /* Register LED Flash class device */
521 ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
522 if (ret < 0)
523 goto err_flash_register;
524
525 aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);
526
527 /* Create V4L2 Flash subdev. */
528 led->v4l2_flash = v4l2_flash_init(dev, sub_node, fled_cdev, NULL,
529 &v4l2_flash_ops, &v4l2_sd_cfg);
530 if (IS_ERR(led->v4l2_flash)) {
531 ret = PTR_ERR(led->v4l2_flash);
532 goto error_v4l2_flash_init;
533 }
534
535 return 0;
536
537 error_v4l2_flash_init:
538 led_classdev_flash_unregister(fled_cdev);
539 err_flash_register:
540 mutex_destroy(&led->lock);
541
542 return ret;
543 }
544
aat1290_led_remove(struct platform_device * pdev)545 static int aat1290_led_remove(struct platform_device *pdev)
546 {
547 struct aat1290_led *led = platform_get_drvdata(pdev);
548
549 v4l2_flash_release(led->v4l2_flash);
550 led_classdev_flash_unregister(&led->fled_cdev);
551 cancel_work_sync(&led->work_brightness_set);
552
553 mutex_destroy(&led->lock);
554
555 return 0;
556 }
557
558 static const struct of_device_id aat1290_led_dt_match[] = {
559 { .compatible = "skyworks,aat1290" },
560 {},
561 };
562 MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);
563
564 static struct platform_driver aat1290_led_driver = {
565 .probe = aat1290_led_probe,
566 .remove = aat1290_led_remove,
567 .driver = {
568 .name = "aat1290",
569 .of_match_table = aat1290_led_dt_match,
570 },
571 };
572
573 module_platform_driver(aat1290_led_driver);
574
575 MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
576 MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
577 MODULE_LICENSE("GPL v2");
578