1/*
2 * LED driver : leds-ktd2692.c
3 *
4 * Copyright (C) 2015 Samsung Electronics
5 * Ingi Kim <ingi2.kim@samsung.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/delay.h>
13#include <linux/err.h>
14#include <linux/gpio/consumer.h>
15#include <linux/led-class-flash.h>
16#include <linux/module.h>
17#include <linux/mutex.h>
18#include <linux/of.h>
19#include <linux/platform_device.h>
20#include <linux/regulator/consumer.h>
21#include <linux/workqueue.h>
22
23/* Value related the movie mode */
24#define KTD2692_MOVIE_MODE_CURRENT_LEVELS	16
25#define KTD2692_MM_TO_FL_RATIO(x)		((x) / 3)
26#define KTD2962_MM_MIN_CURR_THRESHOLD_SCALE	8
27
28/* Value related the flash mode */
29#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS	8
30#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE	0
31#define KTD2692_FLASH_MODE_CURR_PERCENT(x)	(((x) * 16) / 100)
32
33/* Macro for getting offset of flash timeout */
34#define GET_TIMEOUT_OFFSET(timeout, step)	((timeout) / (step))
35
36/* Base register address */
37#define KTD2692_REG_LVP_BASE			0x00
38#define KTD2692_REG_FLASH_TIMEOUT_BASE		0x20
39#define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE	0x40
40#define KTD2692_REG_MOVIE_CURRENT_BASE		0x60
41#define KTD2692_REG_FLASH_CURRENT_BASE		0x80
42#define KTD2692_REG_MODE_BASE			0xA0
43
44/* Set bit coding time for expresswire interface */
45#define KTD2692_TIME_RESET_US			700
46#define KTD2692_TIME_DATA_START_TIME_US		10
47#define KTD2692_TIME_HIGH_END_OF_DATA_US	350
48#define KTD2692_TIME_LOW_END_OF_DATA_US		10
49#define KTD2692_TIME_SHORT_BITSET_US		4
50#define KTD2692_TIME_LONG_BITSET_US		12
51
52/* KTD2692 default length of name */
53#define KTD2692_NAME_LENGTH			20
54
55enum ktd2692_bitset {
56	KTD2692_LOW = 0,
57	KTD2692_HIGH,
58};
59
60/* Movie / Flash Mode Control */
61enum ktd2692_led_mode {
62	KTD2692_MODE_DISABLE = 0,	/* default */
63	KTD2692_MODE_MOVIE,
64	KTD2692_MODE_FLASH,
65};
66
67struct ktd2692_led_config_data {
68	/* maximum LED current in movie mode */
69	u32 movie_max_microamp;
70	/* maximum LED current in flash mode */
71	u32 flash_max_microamp;
72	/* maximum flash timeout */
73	u32 flash_max_timeout;
74	/* max LED brightness level */
75	enum led_brightness max_brightness;
76};
77
78struct ktd2692_context {
79	/* Related LED Flash class device */
80	struct led_classdev_flash fled_cdev;
81
82	/* secures access to the device */
83	struct mutex lock;
84	struct regulator *regulator;
85	struct work_struct work_brightness_set;
86
87	struct gpio_desc *aux_gpio;
88	struct gpio_desc *ctrl_gpio;
89
90	enum ktd2692_led_mode mode;
91	enum led_brightness torch_brightness;
92};
93
94static struct ktd2692_context *fled_cdev_to_led(
95				struct led_classdev_flash *fled_cdev)
96{
97	return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
98}
99
100static void ktd2692_expresswire_start(struct ktd2692_context *led)
101{
102	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
103	udelay(KTD2692_TIME_DATA_START_TIME_US);
104}
105
106static void ktd2692_expresswire_reset(struct ktd2692_context *led)
107{
108	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
109	udelay(KTD2692_TIME_RESET_US);
110}
111
112static void ktd2692_expresswire_end(struct ktd2692_context *led)
113{
114	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
115	udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
116	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
117	udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
118}
119
120static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
121{
122	/*
123	 * The Low Bit(0) and High Bit(1) is based on a time detection
124	 * algorithm between time low and time high
125	 * Time_(L_LB) : Low time of the Low Bit(0)
126	 * Time_(H_LB) : High time of the LOW Bit(0)
127	 * Time_(L_HB) : Low time of the High Bit(1)
128	 * Time_(H_HB) : High time of the High Bit(1)
129	 *
130	 * It can be simplified to:
131	 * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
132	 * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
133	 * HIGH  ___           ____    _..     _________    ___
134	 *          |_________|    |_..  |____|         |__|
135	 * LOW        <L_LB>  <H_LB>     <L_HB>  <H_HB>
136	 *          [  Low Bit (0) ]     [  High Bit(1) ]
137	 */
138	if (bit) {
139		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
140		udelay(KTD2692_TIME_SHORT_BITSET_US);
141		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
142		udelay(KTD2692_TIME_LONG_BITSET_US);
143	} else {
144		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
145		udelay(KTD2692_TIME_LONG_BITSET_US);
146		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
147		udelay(KTD2692_TIME_SHORT_BITSET_US);
148	}
149}
150
151static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
152{
153	int i;
154
155	ktd2692_expresswire_start(led);
156	for (i = 7; i >= 0; i--)
157		ktd2692_expresswire_set_bit(led, value & BIT(i));
158	ktd2692_expresswire_end(led);
159}
160
161static void ktd2692_brightness_set(struct ktd2692_context *led,
162				   enum led_brightness brightness)
163{
164	mutex_lock(&led->lock);
165
166	if (brightness == LED_OFF) {
167		led->mode = KTD2692_MODE_DISABLE;
168		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
169	} else {
170		ktd2692_expresswire_write(led, brightness |
171					KTD2692_REG_MOVIE_CURRENT_BASE);
172		led->mode = KTD2692_MODE_MOVIE;
173	}
174
175	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
176	mutex_unlock(&led->lock);
177}
178
179static void ktd2692_brightness_set_work(struct work_struct *work)
180{
181	struct ktd2692_context *led =
182		container_of(work, struct ktd2692_context, work_brightness_set);
183
184	ktd2692_brightness_set(led, led->torch_brightness);
185}
186
187static void ktd2692_led_brightness_set(struct led_classdev *led_cdev,
188				       enum led_brightness brightness)
189{
190	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
191	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
192
193	led->torch_brightness = brightness;
194	schedule_work(&led->work_brightness_set);
195}
196
197static int ktd2692_led_brightness_set_sync(struct led_classdev *led_cdev,
198					   enum led_brightness brightness)
199{
200	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
201	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
202
203	ktd2692_brightness_set(led, brightness);
204
205	return 0;
206}
207
208static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
209					bool state)
210{
211	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
212	struct led_flash_setting *timeout = &fled_cdev->timeout;
213	u32 flash_tm_reg;
214
215	mutex_lock(&led->lock);
216
217	if (state) {
218		flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
219		ktd2692_expresswire_write(led, flash_tm_reg
220				| KTD2692_REG_FLASH_TIMEOUT_BASE);
221
222		led->mode = KTD2692_MODE_FLASH;
223		gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
224	} else {
225		led->mode = KTD2692_MODE_DISABLE;
226		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
227	}
228
229	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
230
231	fled_cdev->led_cdev.brightness = LED_OFF;
232	led->mode = KTD2692_MODE_DISABLE;
233
234	mutex_unlock(&led->lock);
235
236	return 0;
237}
238
239static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
240					 u32 timeout)
241{
242	return 0;
243}
244
245static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
246{
247	u32 offset, step;
248	u32 movie_current_microamp;
249
250	offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
251	step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
252		/ KTD2692_MOVIE_MODE_CURRENT_LEVELS;
253
254	do {
255		movie_current_microamp = step * offset;
256		offset--;
257	} while ((movie_current_microamp > cfg->movie_max_microamp) &&
258		(offset > 0));
259
260	cfg->max_brightness = offset;
261}
262
263static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
264				       struct ktd2692_led_config_data *cfg)
265{
266	struct led_flash_setting *setting;
267
268	setting = &fled_cdev->timeout;
269	setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
270	setting->max = cfg->flash_max_timeout;
271	setting->step = cfg->flash_max_timeout
272			/ (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
273	setting->val = cfg->flash_max_timeout;
274}
275
276static void ktd2692_setup(struct ktd2692_context *led)
277{
278	led->mode = KTD2692_MODE_DISABLE;
279	ktd2692_expresswire_reset(led);
280	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
281
282	ktd2692_expresswire_write(led, (KTD2962_MM_MIN_CURR_THRESHOLD_SCALE - 1)
283				 | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
284	ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
285				 | KTD2692_REG_FLASH_CURRENT_BASE);
286}
287
288static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
289			    struct ktd2692_led_config_data *cfg)
290{
291	struct device_node *np = dev->of_node;
292	struct device_node *child_node;
293	int ret;
294
295	if (!dev->of_node)
296		return -ENXIO;
297
298	led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
299	if (IS_ERR(led->ctrl_gpio)) {
300		ret = PTR_ERR(led->ctrl_gpio);
301		dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
302		return ret;
303	}
304
305	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
306	if (IS_ERR(led->aux_gpio)) {
307		ret = PTR_ERR(led->aux_gpio);
308		dev_err(dev, "cannot get aux-gpios %d\n", ret);
309		return ret;
310	}
311
312	led->regulator = devm_regulator_get(dev, "vin");
313	if (IS_ERR(led->regulator))
314		led->regulator = NULL;
315
316	if (led->regulator) {
317		ret = regulator_enable(led->regulator);
318		if (ret)
319			dev_err(dev, "Failed to enable supply: %d\n", ret);
320	}
321
322	child_node = of_get_next_available_child(np, NULL);
323	if (!child_node) {
324		dev_err(dev, "No DT child node found for connected LED.\n");
325		return -EINVAL;
326	}
327
328	led->fled_cdev.led_cdev.name =
329		of_get_property(child_node, "label", NULL) ? : child_node->name;
330
331	ret = of_property_read_u32(child_node, "led-max-microamp",
332				   &cfg->movie_max_microamp);
333	if (ret) {
334		dev_err(dev, "failed to parse led-max-microamp\n");
335		return ret;
336	}
337
338	ret = of_property_read_u32(child_node, "flash-max-microamp",
339				   &cfg->flash_max_microamp);
340	if (ret) {
341		dev_err(dev, "failed to parse flash-max-microamp\n");
342		return ret;
343	}
344
345	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
346				   &cfg->flash_max_timeout);
347	if (ret)
348		dev_err(dev, "failed to parse flash-max-timeout-us\n");
349
350	of_node_put(child_node);
351	return ret;
352}
353
354static const struct led_flash_ops flash_ops = {
355	.strobe_set = ktd2692_led_flash_strobe_set,
356	.timeout_set = ktd2692_led_flash_timeout_set,
357};
358
359static int ktd2692_probe(struct platform_device *pdev)
360{
361	struct ktd2692_context *led;
362	struct led_classdev *led_cdev;
363	struct led_classdev_flash *fled_cdev;
364	struct ktd2692_led_config_data led_cfg;
365	int ret;
366
367	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
368	if (!led)
369		return -ENOMEM;
370
371	fled_cdev = &led->fled_cdev;
372	led_cdev = &fled_cdev->led_cdev;
373
374	ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
375	if (ret)
376		return ret;
377
378	ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
379	ktd2692_init_movie_current_max(&led_cfg);
380
381	fled_cdev->ops = &flash_ops;
382
383	led_cdev->max_brightness = led_cfg.max_brightness;
384	led_cdev->brightness_set = ktd2692_led_brightness_set;
385	led_cdev->brightness_set_sync = ktd2692_led_brightness_set_sync;
386	led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
387
388	mutex_init(&led->lock);
389	INIT_WORK(&led->work_brightness_set, ktd2692_brightness_set_work);
390
391	platform_set_drvdata(pdev, led);
392
393	ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
394	if (ret) {
395		dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
396		mutex_destroy(&led->lock);
397		return ret;
398	}
399
400	ktd2692_setup(led);
401
402	return 0;
403}
404
405static int ktd2692_remove(struct platform_device *pdev)
406{
407	struct ktd2692_context *led = platform_get_drvdata(pdev);
408	int ret;
409
410	led_classdev_flash_unregister(&led->fled_cdev);
411	cancel_work_sync(&led->work_brightness_set);
412
413	if (led->regulator) {
414		ret = regulator_disable(led->regulator);
415		if (ret)
416			dev_err(&pdev->dev,
417				"Failed to disable supply: %d\n", ret);
418	}
419
420	mutex_destroy(&led->lock);
421
422	return 0;
423}
424
425static const struct of_device_id ktd2692_match[] = {
426	{ .compatible = "kinetic,ktd2692", },
427	{ /* sentinel */ },
428};
429MODULE_DEVICE_TABLE(of, ktd2692_match);
430
431static struct platform_driver ktd2692_driver = {
432	.driver = {
433		.name  = "ktd2692",
434		.of_match_table = ktd2692_match,
435	},
436	.probe  = ktd2692_probe,
437	.remove = ktd2692_remove,
438};
439
440module_platform_driver(ktd2692_driver);
441
442MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
443MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
444MODULE_LICENSE("GPL v2");
445