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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 static const int max_mm_current_percent[] = {
318 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
319 63, 71, 79, 89, 100
320 };
321 int i, max_mm_current =
322 AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
323
324 led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
325 sizeof(max_mm_current_percent),
326 GFP_KERNEL);
327 if (!led->mm_current_scale)
328 return -ENOMEM;
329
330 for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
331 led->mm_current_scale[i] = max_mm_current *
332 max_mm_current_percent[i] / 100;
333
334 return 0;
335}
336
337static int aat1290_led_get_configuration(struct aat1290_led *led,
338 struct aat1290_led_config_data *cfg,
339 struct device_node **sub_node)
340{
341 int ret;
342
343 ret = aat1290_led_parse_dt(led, cfg, sub_node);
344 if (ret < 0)
345 return ret;
346 /*
347 * Init non-linear movie mode current scale basing
348 * on the max flash current from led configuration.
349 */
350 ret = init_mm_current_scale(led, cfg);
351 if (ret < 0)
352 return ret;
353
354 aat1290_led_validate_mm_current(led, cfg);
355
356#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
357#else
358 devm_kfree(&led->pdev->dev, led->mm_current_scale);
359#endif
360
361 return 0;
362}
363
364static void aat1290_init_flash_timeout(struct aat1290_led *led,
365 struct aat1290_led_config_data *cfg)
366{
367 struct led_classdev_flash *fled_cdev = &led->fled_cdev;
368 struct led_flash_setting *setting;
369
370 /* Init flash timeout setting */
371 setting = &fled_cdev->timeout;
372 setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
373 setting->max = cfg->max_flash_tm;
374 setting->step = setting->min;
375 setting->val = setting->max;
376}
377
378#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
379static enum led_brightness aat1290_intensity_to_brightness(
380 struct v4l2_flash *v4l2_flash,
381 s32 intensity)
382{
383 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
384 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
385 int i;
386
387 for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
388 if (intensity >= led->mm_current_scale[i])
389 return i + 1;
390
391 return 1;
392}
393
394static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
395 enum led_brightness brightness)
396{
397 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
398 struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
399
400 return led->mm_current_scale[brightness - 1];
401}
402
403static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
404 bool enable)
405{
406 struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
407 struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
408 struct led_classdev *led_cdev = &fled_cdev->led_cdev;
409 struct pinctrl *pinctrl;
410
411 gpiod_direction_output(led->gpio_fl_en, 0);
412 gpiod_direction_output(led->gpio_en_set, 0);
413
414 led->movie_mode = false;
415 led_cdev->brightness = 0;
416
417 pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
418 enable ? "isp" : "host");
419 if (IS_ERR(pinctrl)) {
420 dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
421 return PTR_ERR(pinctrl);
422 }
423
424 return 0;
425}
426
427static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
428 struct aat1290_led_config_data *led_cfg,
429 struct v4l2_flash_config *v4l2_sd_cfg)
430{
431 struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
432 struct led_flash_setting *s;
433
434 strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
435 sizeof(v4l2_sd_cfg->dev_name));
436
437 s = &v4l2_sd_cfg->intensity;
438 s->min = led->mm_current_scale[0];
439 s->max = led_cfg->max_mm_current;
440 s->step = 1;
441 s->val = s->max;
442
443 v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
444}
445
446static const struct v4l2_flash_ops v4l2_flash_ops = {
447 .external_strobe_set = aat1290_led_external_strobe_set,
448 .intensity_to_led_brightness = aat1290_intensity_to_brightness,
449 .led_brightness_to_intensity = aat1290_brightness_to_intensity,
450};
451#else
452static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
453 struct aat1290_led_config_data *led_cfg,
454 struct v4l2_flash_config *v4l2_sd_cfg)
455{
456}
457static const struct v4l2_flash_ops v4l2_flash_ops;
458#endif
459
460static const struct led_flash_ops flash_ops = {
461 .strobe_set = aat1290_led_flash_strobe_set,
462 .timeout_set = aat1290_led_flash_timeout_set,
463};
464
465static int aat1290_led_probe(struct platform_device *pdev)
466{
467 struct device *dev = &pdev->dev;
468 struct device_node *sub_node = NULL;
469 struct aat1290_led *led;
470 struct led_classdev *led_cdev;
471 struct led_classdev_flash *fled_cdev;
472 struct aat1290_led_config_data led_cfg = {};
473 struct v4l2_flash_config v4l2_sd_cfg = {};
474 int ret;
475
476 led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
477 if (!led)
478 return -ENOMEM;
479
480 led->pdev = pdev;
481 platform_set_drvdata(pdev, led);
482
483 fled_cdev = &led->fled_cdev;
484 fled_cdev->ops = &flash_ops;
485 led_cdev = &fled_cdev->led_cdev;
486
487 ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
488 if (ret < 0)
489 return ret;
490
491 mutex_init(&led->lock);
492
493 /* Initialize LED Flash class device */
494 led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
495 led_cdev->max_brightness = led_cfg.max_brightness;
496 led_cdev->flags |= LED_DEV_CAP_FLASH;
497
498 aat1290_init_flash_timeout(led, &led_cfg);
499
500 /* Register LED Flash class device */
501 ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
502 if (ret < 0)
503 goto err_flash_register;
504
505 aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);
506
507 /* Create V4L2 Flash subdev. */
508 led->v4l2_flash = v4l2_flash_init(dev, of_fwnode_handle(sub_node),
509 fled_cdev, &v4l2_flash_ops,
510 &v4l2_sd_cfg);
511 if (IS_ERR(led->v4l2_flash)) {
512 ret = PTR_ERR(led->v4l2_flash);
513 goto error_v4l2_flash_init;
514 }
515
516 return 0;
517
518error_v4l2_flash_init:
519 led_classdev_flash_unregister(fled_cdev);
520err_flash_register:
521 mutex_destroy(&led->lock);
522
523 return ret;
524}
525
526static int aat1290_led_remove(struct platform_device *pdev)
527{
528 struct aat1290_led *led = platform_get_drvdata(pdev);
529
530 v4l2_flash_release(led->v4l2_flash);
531 led_classdev_flash_unregister(&led->fled_cdev);
532
533 mutex_destroy(&led->lock);
534
535 return 0;
536}
537
538static const struct of_device_id aat1290_led_dt_match[] = {
539 { .compatible = "skyworks,aat1290" },
540 {},
541};
542MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);
543
544static struct platform_driver aat1290_led_driver = {
545 .probe = aat1290_led_probe,
546 .remove = aat1290_led_remove,
547 .driver = {
548 .name = "aat1290",
549 .of_match_table = aat1290_led_dt_match,
550 },
551};
552
553module_platform_driver(aat1290_led_driver);
554
555MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
556MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
557MODULE_LICENSE("GPL v2");