leds-aat1290.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *	LED Flash class driver for the AAT1290
  4 *	1.5A Step-Up Current Regulator for Flash LEDs
  5 *
  6 *	Copyright (C) 2015, Samsung Electronics Co., Ltd.
  7 *	Author: Jacek Anaszewski <j.anaszewski@samsung.com>
  8 */
  9
 10#include <linux/cleanup.h>
 11#include <linux/delay.h>
 12#include <linux/gpio/consumer.h>
 13#include <linux/led-class-flash.h>
 14#include <linux/leds.h>
 15#include <linux/module.h>
 16#include <linux/mutex.h>
 17#include <linux/of.h>
 18#include <linux/pinctrl/consumer.h>
 19#include <linux/platform_device.h>
 20#include <linux/slab.h>
 21#include <media/v4l2-flash-led-class.h>
 22
 23#define AAT1290_MOVIE_MODE_CURRENT_ADDR	17
 24#define AAT1290_MAX_MM_CURR_PERCENT_0	16
 25#define AAT1290_MAX_MM_CURR_PERCENT_100	1
 26
 27#define AAT1290_FLASH_SAFETY_TIMER_ADDR	18
 28
 29#define AAT1290_MOVIE_MODE_CONFIG_ADDR	19
 30#define AAT1290_MOVIE_MODE_OFF		1
 31#define AAT1290_MOVIE_MODE_ON		3
 32
 33#define AAT1290_MM_CURRENT_RATIO_ADDR	20
 34#define AAT1290_MM_TO_FL_1_92		1
 35
 36#define AAT1290_MM_TO_FL_RATIO		1000 / 1920
 37#define AAT1290_MAX_MM_CURRENT(fl_max)	(fl_max * AAT1290_MM_TO_FL_RATIO)
 38
 39#define AAT1290_LATCH_TIME_MIN_US	500
 40#define AAT1290_LATCH_TIME_MAX_US	1000
 41#define AAT1290_EN_SET_TICK_TIME_US	1
 42#define AAT1290_FLEN_OFF_DELAY_TIME_US	10
 43#define AAT1290_FLASH_TM_NUM_LEVELS	16
 44#define AAT1290_MM_CURRENT_SCALE_SIZE	15
 45
 46#define AAT1290_NAME			"aat1290"
 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
 83static struct aat1290_led *fled_cdev_to_led(
 84				struct led_classdev_flash *fled_cdev)
 85{
 86	return container_of(fled_cdev, struct aat1290_led, fled_cdev);
 87}
 88
 89static struct led_classdev_flash *led_cdev_to_fled_cdev(
 90				struct led_classdev *led_cdev)
 91{
 92	return container_of(led_cdev, struct led_classdev_flash, led_cdev);
 93}
 94
 95static 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
125static 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
137/* LED subsystem callbacks */
138
139static int aat1290_led_brightness_set(struct led_classdev *led_cdev,
140					enum led_brightness brightness)
141{
142	struct led_classdev_flash *fled_cdev = led_cdev_to_fled_cdev(led_cdev);
143	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
144
145	mutex_lock(&led->lock);
146
147	if (brightness == 0) {
148		gpiod_direction_output(led->gpio_fl_en, 0);
149		gpiod_direction_output(led->gpio_en_set, 0);
150		led->movie_mode = false;
151	} else {
152		if (!led->movie_mode) {
153			aat1290_as2cwire_write(led,
154				AAT1290_MM_CURRENT_RATIO_ADDR,
155				AAT1290_MM_TO_FL_1_92);
156			led->movie_mode = true;
157		}
158
159		aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
160				AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
161		aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
162				AAT1290_MOVIE_MODE_ON);
163	}
164
165	mutex_unlock(&led->lock);
166
167	return 0;
168}
169
170static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
171					 bool state)
172
173{
174	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
175	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
176	struct led_flash_setting *timeout = &fled_cdev->timeout;
177
178	mutex_lock(&led->lock);
179
180	if (state) {
181		aat1290_set_flash_safety_timer(led, timeout->val);
182		gpiod_direction_output(led->gpio_fl_en, 1);
183	} else {
184		gpiod_direction_output(led->gpio_fl_en, 0);
185		gpiod_direction_output(led->gpio_en_set, 0);
186	}
187
188	/*
189	 * To reenter movie mode after a flash event the part must be cycled
190	 * off and back on to reset the movie mode and reprogrammed via the
191	 * AS2Cwire. Therefore the brightness and movie_mode properties needs
192	 * to be updated here to reflect the actual state.
193	 */
194	led_cdev->brightness = 0;
195	led->movie_mode = false;
196
197	mutex_unlock(&led->lock);
198
199	return 0;
200}
201
202static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
203						u32 timeout)
204{
205	/*
206	 * Don't do anything - flash timeout is cached in the led-class-flash
207	 * core and will be applied in the strobe_set op, as writing the
208	 * safety timer register spuriously turns the torch mode on.
209	 */
210
211	return 0;
212}
213
214static int aat1290_led_parse_dt(struct aat1290_led *led,
215			struct aat1290_led_config_data *cfg,
216			struct device_node **sub_node)
217{
218	struct device *dev = &led->pdev->dev;
219#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
220	struct pinctrl *pinctrl;
221#endif
222	int ret = 0;
223
224	led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
225	if (IS_ERR(led->gpio_fl_en)) {
226		ret = PTR_ERR(led->gpio_fl_en);
227		dev_err(dev, "Unable to claim gpio \"flen\".\n");
228		return ret;
229	}
230
231	led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
232	if (IS_ERR(led->gpio_en_set)) {
233		ret = PTR_ERR(led->gpio_en_set);
234		dev_err(dev, "Unable to claim gpio \"enset\".\n");
235		return ret;
236	}
237
238#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
239	pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
240	if (IS_ERR(pinctrl)) {
241		cfg->has_external_strobe = false;
242		dev_info(dev,
243			 "No support for external strobe detected.\n");
244	} else {
245		cfg->has_external_strobe = true;
246	}
247#endif
248
249	struct device_node *child_node __free(device_node) =
250		of_get_next_available_child(dev_of_node(dev), NULL);
251	if (!child_node) {
252		dev_err(dev, "No DT child node found for connected LED.\n");
253		return -EINVAL;
254	}
255
256	ret = of_property_read_u32(child_node, "led-max-microamp",
257				&cfg->max_mm_current);
258	/*
259	 * led-max-microamp will default to 1/20 of flash-max-microamp
260	 * in case it is missing.
261	 */
262	if (ret < 0)
263		dev_warn(dev,
264			"led-max-microamp DT property missing\n");
265
266	ret = of_property_read_u32(child_node, "flash-max-microamp",
267				&cfg->max_flash_current);
268	if (ret < 0) {
269		dev_err(dev,
270			"flash-max-microamp DT property missing\n");
271		return ret;
272	}
273
274	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
275				&cfg->max_flash_tm);
276	if (ret < 0) {
277		dev_err(dev,
278			"flash-max-timeout-us DT property missing\n");
279		return ret;
280	}
281
282	*sub_node = child_node;
283
284	return 0;
285}
286
287static void aat1290_led_validate_mm_current(struct aat1290_led *led,
288					struct aat1290_led_config_data *cfg)
289{
290	int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;
291
292	while (e - b > 1) {
293		i = b + (e - b) / 2;
294		if (cfg->max_mm_current < led->mm_current_scale[i])
295			e = i;
296		else
297			b = i;
298	}
299
300	cfg->max_mm_current = led->mm_current_scale[b];
301	cfg->max_brightness = b + 1;
302}
303
304static int init_mm_current_scale(struct aat1290_led *led,
305			struct aat1290_led_config_data *cfg)
306{
307	static const int max_mm_current_percent[] = {
308		20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
309		63, 71, 79, 89, 100
310	};
311	int i, max_mm_current =
312			AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);
313
314	led->mm_current_scale = devm_kzalloc(&led->pdev->dev,
315					sizeof(max_mm_current_percent),
316					GFP_KERNEL);
317	if (!led->mm_current_scale)
318		return -ENOMEM;
319
320	for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
321		led->mm_current_scale[i] = max_mm_current *
322					  max_mm_current_percent[i] / 100;
323
324	return 0;
325}
326
327static int aat1290_led_get_configuration(struct aat1290_led *led,
328					struct aat1290_led_config_data *cfg,
329					struct device_node **sub_node)
330{
331	int ret;
332
333	ret = aat1290_led_parse_dt(led, cfg, sub_node);
334	if (ret < 0)
335		return ret;
336	/*
337	 * Init non-linear movie mode current scale basing
338	 * on the max flash current from led configuration.
339	 */
340	ret = init_mm_current_scale(led, cfg);
341	if (ret < 0)
342		return ret;
343
344	aat1290_led_validate_mm_current(led, cfg);
345
346#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
347#else
348	devm_kfree(&led->pdev->dev, led->mm_current_scale);
349#endif
350
351	return 0;
352}
353
354static void aat1290_init_flash_timeout(struct aat1290_led *led,
355				struct aat1290_led_config_data *cfg)
356{
357	struct led_classdev_flash *fled_cdev = &led->fled_cdev;
358	struct led_flash_setting *setting;
359
360	/* Init flash timeout setting */
361	setting = &fled_cdev->timeout;
362	setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
363	setting->max = cfg->max_flash_tm;
364	setting->step = setting->min;
365	setting->val = setting->max;
366}
367
368#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
369static enum led_brightness aat1290_intensity_to_brightness(
370					struct v4l2_flash *v4l2_flash,
371					s32 intensity)
372{
373	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
374	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
375	int i;
376
377	for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
378		if (intensity >= led->mm_current_scale[i])
379			return i + 1;
380
381	return 1;
382}
383
384static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
385					enum led_brightness brightness)
386{
387	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
388	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
389
390	return led->mm_current_scale[brightness - 1];
391}
392
393static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
394						bool enable)
395{
396	struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
397	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
398	struct led_classdev *led_cdev = &fled_cdev->led_cdev;
399	struct pinctrl *pinctrl;
400
401	gpiod_direction_output(led->gpio_fl_en, 0);
402	gpiod_direction_output(led->gpio_en_set, 0);
403
404	led->movie_mode = false;
405	led_cdev->brightness = 0;
406
407	pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
408						enable ? "isp" : "host");
409	if (IS_ERR(pinctrl)) {
410		dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
411		return PTR_ERR(pinctrl);
412	}
413
414	return 0;
415}
416
417static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
418					struct aat1290_led_config_data *led_cfg,
419					struct v4l2_flash_config *v4l2_sd_cfg)
420{
421	struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
422	struct led_flash_setting *s;
423
424	strscpy(v4l2_sd_cfg->dev_name, led_cdev->dev->kobj.name,
425		sizeof(v4l2_sd_cfg->dev_name));
426
427	s = &v4l2_sd_cfg->intensity;
428	s->min = led->mm_current_scale[0];
429	s->max = led_cfg->max_mm_current;
430	s->step = 1;
431	s->val = s->max;
432
433	v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
434}
435
436static const struct v4l2_flash_ops v4l2_flash_ops = {
437	.external_strobe_set = aat1290_led_external_strobe_set,
438	.intensity_to_led_brightness = aat1290_intensity_to_brightness,
439	.led_brightness_to_intensity = aat1290_brightness_to_intensity,
440};
441#else
442static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
443				struct aat1290_led_config_data *led_cfg,
444				struct v4l2_flash_config *v4l2_sd_cfg)
445{
446}
447static const struct v4l2_flash_ops v4l2_flash_ops;
448#endif
449
450static const struct led_flash_ops flash_ops = {
451	.strobe_set = aat1290_led_flash_strobe_set,
452	.timeout_set = aat1290_led_flash_timeout_set,
453};
454
455static int aat1290_led_probe(struct platform_device *pdev)
456{
457	struct device *dev = &pdev->dev;
458	struct device_node *sub_node = NULL;
459	struct aat1290_led *led;
460	struct led_classdev *led_cdev;
461	struct led_classdev_flash *fled_cdev;
462	struct led_init_data init_data = {};
463	struct aat1290_led_config_data led_cfg = {};
464	struct v4l2_flash_config v4l2_sd_cfg = {};
465	int ret;
466
467	led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
468	if (!led)
469		return -ENOMEM;
470
471	led->pdev = pdev;
472	platform_set_drvdata(pdev, led);
473
474	fled_cdev = &led->fled_cdev;
475	fled_cdev->ops = &flash_ops;
476	led_cdev = &fled_cdev->led_cdev;
477
478	ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
479	if (ret < 0)
480		return ret;
481
482	mutex_init(&led->lock);
483
484	/* Initialize LED Flash class device */
485	led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
486	led_cdev->max_brightness = led_cfg.max_brightness;
487	led_cdev->flags |= LED_DEV_CAP_FLASH;
488
489	aat1290_init_flash_timeout(led, &led_cfg);
490
491	init_data.fwnode = of_fwnode_handle(sub_node);
492	init_data.devicename = AAT1290_NAME;
493
494	/* Register LED Flash class device */
495	ret = led_classdev_flash_register_ext(&pdev->dev, fled_cdev,
496					      &init_data);
497	if (ret < 0)
498		goto err_flash_register;
499
500	aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);
501
502	/* Create V4L2 Flash subdev. */
503	led->v4l2_flash = v4l2_flash_init(dev, of_fwnode_handle(sub_node),
504					  fled_cdev, &v4l2_flash_ops,
505					  &v4l2_sd_cfg);
506	if (IS_ERR(led->v4l2_flash)) {
507		ret = PTR_ERR(led->v4l2_flash);
508		goto error_v4l2_flash_init;
509	}
510
511	return 0;
512
513error_v4l2_flash_init:
514	led_classdev_flash_unregister(fled_cdev);
515err_flash_register:
516	mutex_destroy(&led->lock);
517
518	return ret;
519}
520
521static void aat1290_led_remove(struct platform_device *pdev)
522{
523	struct aat1290_led *led = platform_get_drvdata(pdev);
524
525	v4l2_flash_release(led->v4l2_flash);
526	led_classdev_flash_unregister(&led->fled_cdev);
527
528	mutex_destroy(&led->lock);
529}
530
531static const struct of_device_id aat1290_led_dt_match[] = {
532	{ .compatible = "skyworks,aat1290" },
533	{},
534};
535MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);
536
537static struct platform_driver aat1290_led_driver = {
538	.probe		= aat1290_led_probe,
539	.remove		= aat1290_led_remove,
540	.driver		= {
541		.name	= "aat1290",
542		.of_match_table = aat1290_led_dt_match,
543	},
544};
545
546module_platform_driver(aat1290_led_driver);
547
548MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
549MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
550MODULE_LICENSE("GPL v2");