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