1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LED driver : leds-ktd2692.c
4  *
5  * Copyright (C) 2015 Samsung Electronics
6  * Ingi Kim <ingi2.kim@samsung.com>
7  */
8 
9 #include <linux/delay.h>
10 #include <linux/err.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/led-class-flash.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/regulator/consumer.h>
18 
19 /* Value related the movie mode */
20 #define KTD2692_MOVIE_MODE_CURRENT_LEVELS	16
21 #define KTD2692_MM_TO_FL_RATIO(x)		((x) / 3)
22 #define KTD2692_MM_MIN_CURR_THRESHOLD_SCALE	8
23 
24 /* Value related the flash mode */
25 #define KTD2692_FLASH_MODE_TIMEOUT_LEVELS	8
26 #define KTD2692_FLASH_MODE_TIMEOUT_DISABLE	0
27 #define KTD2692_FLASH_MODE_CURR_PERCENT(x)	(((x) * 16) / 100)
28 
29 /* Macro for getting offset of flash timeout */
30 #define GET_TIMEOUT_OFFSET(timeout, step)	((timeout) / (step))
31 
32 /* Base register address */
33 #define KTD2692_REG_LVP_BASE			0x00
34 #define KTD2692_REG_FLASH_TIMEOUT_BASE		0x20
35 #define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE	0x40
36 #define KTD2692_REG_MOVIE_CURRENT_BASE		0x60
37 #define KTD2692_REG_FLASH_CURRENT_BASE		0x80
38 #define KTD2692_REG_MODE_BASE			0xA0
39 
40 /* Set bit coding time for expresswire interface */
41 #define KTD2692_TIME_RESET_US			700
42 #define KTD2692_TIME_DATA_START_TIME_US		10
43 #define KTD2692_TIME_HIGH_END_OF_DATA_US	350
44 #define KTD2692_TIME_LOW_END_OF_DATA_US		10
45 #define KTD2692_TIME_SHORT_BITSET_US		4
46 #define KTD2692_TIME_LONG_BITSET_US		12
47 
48 /* KTD2692 default length of name */
49 #define KTD2692_NAME_LENGTH			20
50 
51 enum ktd2692_bitset {
52 	KTD2692_LOW = 0,
53 	KTD2692_HIGH,
54 };
55 
56 /* Movie / Flash Mode Control */
57 enum ktd2692_led_mode {
58 	KTD2692_MODE_DISABLE = 0,	/* default */
59 	KTD2692_MODE_MOVIE,
60 	KTD2692_MODE_FLASH,
61 };
62 
63 struct ktd2692_led_config_data {
64 	/* maximum LED current in movie mode */
65 	u32 movie_max_microamp;
66 	/* maximum LED current in flash mode */
67 	u32 flash_max_microamp;
68 	/* maximum flash timeout */
69 	u32 flash_max_timeout;
70 	/* max LED brightness level */
71 	enum led_brightness max_brightness;
72 };
73 
74 struct ktd2692_context {
75 	/* Related LED Flash class device */
76 	struct led_classdev_flash fled_cdev;
77 
78 	/* secures access to the device */
79 	struct mutex lock;
80 	struct regulator *regulator;
81 
82 	struct gpio_desc *aux_gpio;
83 	struct gpio_desc *ctrl_gpio;
84 
85 	enum ktd2692_led_mode mode;
86 	enum led_brightness torch_brightness;
87 };
88 
89 static struct ktd2692_context *fled_cdev_to_led(
90 				struct led_classdev_flash *fled_cdev)
91 {
92 	return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
93 }
94 
95 static void ktd2692_expresswire_start(struct ktd2692_context *led)
96 {
97 	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
98 	udelay(KTD2692_TIME_DATA_START_TIME_US);
99 }
100 
101 static void ktd2692_expresswire_reset(struct ktd2692_context *led)
102 {
103 	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
104 	udelay(KTD2692_TIME_RESET_US);
105 }
106 
107 static void ktd2692_expresswire_end(struct ktd2692_context *led)
108 {
109 	gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
110 	udelay(KTD2692_TIME_LOW_END_OF_DATA_US);
111 	gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
112 	udelay(KTD2692_TIME_HIGH_END_OF_DATA_US);
113 }
114 
115 static void ktd2692_expresswire_set_bit(struct ktd2692_context *led, bool bit)
116 {
117 	/*
118 	 * The Low Bit(0) and High Bit(1) is based on a time detection
119 	 * algorithm between time low and time high
120 	 * Time_(L_LB) : Low time of the Low Bit(0)
121 	 * Time_(H_LB) : High time of the LOW Bit(0)
122 	 * Time_(L_HB) : Low time of the High Bit(1)
123 	 * Time_(H_HB) : High time of the High Bit(1)
124 	 *
125 	 * It can be simplified to:
126 	 * Low Bit(0) : 2 * Time_(H_LB) < Time_(L_LB)
127 	 * High Bit(1) : 2 * Time_(L_HB) < Time_(H_HB)
128 	 * HIGH  ___           ____    _..     _________    ___
129 	 *          |_________|    |_..  |____|         |__|
130 	 * LOW        <L_LB>  <H_LB>     <L_HB>  <H_HB>
131 	 *          [  Low Bit (0) ]     [  High Bit(1) ]
132 	 */
133 	if (bit) {
134 		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
135 		udelay(KTD2692_TIME_SHORT_BITSET_US);
136 		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
137 		udelay(KTD2692_TIME_LONG_BITSET_US);
138 	} else {
139 		gpiod_direction_output(led->ctrl_gpio, KTD2692_LOW);
140 		udelay(KTD2692_TIME_LONG_BITSET_US);
141 		gpiod_direction_output(led->ctrl_gpio, KTD2692_HIGH);
142 		udelay(KTD2692_TIME_SHORT_BITSET_US);
143 	}
144 }
145 
146 static void ktd2692_expresswire_write(struct ktd2692_context *led, u8 value)
147 {
148 	int i;
149 
150 	ktd2692_expresswire_start(led);
151 	for (i = 7; i >= 0; i--)
152 		ktd2692_expresswire_set_bit(led, value & BIT(i));
153 	ktd2692_expresswire_end(led);
154 }
155 
156 static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
157 				       enum led_brightness brightness)
158 {
159 	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
160 	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
161 
162 	mutex_lock(&led->lock);
163 
164 	if (brightness == LED_OFF) {
165 		led->mode = KTD2692_MODE_DISABLE;
166 		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
167 	} else {
168 		ktd2692_expresswire_write(led, brightness |
169 					KTD2692_REG_MOVIE_CURRENT_BASE);
170 		led->mode = KTD2692_MODE_MOVIE;
171 	}
172 
173 	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
174 	mutex_unlock(&led->lock);
175 
176 	return 0;
177 }
178 
179 static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
180 					bool state)
181 {
182 	struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
183 	struct led_flash_setting *timeout = &fled_cdev->timeout;
184 	u32 flash_tm_reg;
185 
186 	mutex_lock(&led->lock);
187 
188 	if (state) {
189 		flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
190 		ktd2692_expresswire_write(led, flash_tm_reg
191 				| KTD2692_REG_FLASH_TIMEOUT_BASE);
192 
193 		led->mode = KTD2692_MODE_FLASH;
194 		gpiod_direction_output(led->aux_gpio, KTD2692_HIGH);
195 	} else {
196 		led->mode = KTD2692_MODE_DISABLE;
197 		gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
198 	}
199 
200 	ktd2692_expresswire_write(led, led->mode | KTD2692_REG_MODE_BASE);
201 
202 	fled_cdev->led_cdev.brightness = LED_OFF;
203 	led->mode = KTD2692_MODE_DISABLE;
204 
205 	mutex_unlock(&led->lock);
206 
207 	return 0;
208 }
209 
210 static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
211 					 u32 timeout)
212 {
213 	return 0;
214 }
215 
216 static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
217 {
218 	u32 offset, step;
219 	u32 movie_current_microamp;
220 
221 	offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
222 	step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
223 		/ KTD2692_MOVIE_MODE_CURRENT_LEVELS;
224 
225 	do {
226 		movie_current_microamp = step * offset;
227 		offset--;
228 	} while ((movie_current_microamp > cfg->movie_max_microamp) &&
229 		(offset > 0));
230 
231 	cfg->max_brightness = offset;
232 }
233 
234 static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
235 				       struct ktd2692_led_config_data *cfg)
236 {
237 	struct led_flash_setting *setting;
238 
239 	setting = &fled_cdev->timeout;
240 	setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
241 	setting->max = cfg->flash_max_timeout;
242 	setting->step = cfg->flash_max_timeout
243 			/ (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
244 	setting->val = cfg->flash_max_timeout;
245 }
246 
247 static void ktd2692_setup(struct ktd2692_context *led)
248 {
249 	led->mode = KTD2692_MODE_DISABLE;
250 	ktd2692_expresswire_reset(led);
251 	gpiod_direction_output(led->aux_gpio, KTD2692_LOW);
252 
253 	ktd2692_expresswire_write(led, (KTD2692_MM_MIN_CURR_THRESHOLD_SCALE - 1)
254 				 | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
255 	ktd2692_expresswire_write(led, KTD2692_FLASH_MODE_CURR_PERCENT(45)
256 				 | KTD2692_REG_FLASH_CURRENT_BASE);
257 }
258 
259 static void regulator_disable_action(void *_data)
260 {
261 	struct device *dev = _data;
262 	struct ktd2692_context *led = dev_get_drvdata(dev);
263 	int ret;
264 
265 	ret = regulator_disable(led->regulator);
266 	if (ret)
267 		dev_err(dev, "Failed to disable supply: %d\n", ret);
268 }
269 
270 static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
271 			    struct ktd2692_led_config_data *cfg)
272 {
273 	struct device_node *np = dev_of_node(dev);
274 	struct device_node *child_node;
275 	int ret;
276 
277 	if (!dev_of_node(dev))
278 		return -ENXIO;
279 
280 	led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
281 	ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
282 	if (ret) {
283 		dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
284 		return ret;
285 	}
286 
287 	led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
288 	ret = PTR_ERR_OR_ZERO(led->aux_gpio);
289 	if (ret) {
290 		dev_err(dev, "cannot get aux-gpios %d\n", ret);
291 		return ret;
292 	}
293 
294 	led->regulator = devm_regulator_get(dev, "vin");
295 	if (IS_ERR(led->regulator))
296 		led->regulator = NULL;
297 
298 	if (led->regulator) {
299 		ret = regulator_enable(led->regulator);
300 		if (ret) {
301 			dev_err(dev, "Failed to enable supply: %d\n", ret);
302 		} else {
303 			ret = devm_add_action_or_reset(dev,
304 						regulator_disable_action, dev);
305 			if (ret)
306 				return ret;
307 		}
308 	}
309 
310 	child_node = of_get_next_available_child(np, NULL);
311 	if (!child_node) {
312 		dev_err(dev, "No DT child node found for connected LED.\n");
313 		return -EINVAL;
314 	}
315 
316 	led->fled_cdev.led_cdev.name =
317 		of_get_property(child_node, "label", NULL) ? : child_node->name;
318 
319 	ret = of_property_read_u32(child_node, "led-max-microamp",
320 				   &cfg->movie_max_microamp);
321 	if (ret) {
322 		dev_err(dev, "failed to parse led-max-microamp\n");
323 		goto err_parse_dt;
324 	}
325 
326 	ret = of_property_read_u32(child_node, "flash-max-microamp",
327 				   &cfg->flash_max_microamp);
328 	if (ret) {
329 		dev_err(dev, "failed to parse flash-max-microamp\n");
330 		goto err_parse_dt;
331 	}
332 
333 	ret = of_property_read_u32(child_node, "flash-max-timeout-us",
334 				   &cfg->flash_max_timeout);
335 	if (ret) {
336 		dev_err(dev, "failed to parse flash-max-timeout-us\n");
337 		goto err_parse_dt;
338 	}
339 
340 err_parse_dt:
341 	of_node_put(child_node);
342 	return ret;
343 }
344 
345 static const struct led_flash_ops flash_ops = {
346 	.strobe_set = ktd2692_led_flash_strobe_set,
347 	.timeout_set = ktd2692_led_flash_timeout_set,
348 };
349 
350 static int ktd2692_probe(struct platform_device *pdev)
351 {
352 	struct ktd2692_context *led;
353 	struct led_classdev *led_cdev;
354 	struct led_classdev_flash *fled_cdev;
355 	struct ktd2692_led_config_data led_cfg;
356 	int ret;
357 
358 	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
359 	if (!led)
360 		return -ENOMEM;
361 
362 	fled_cdev = &led->fled_cdev;
363 	led_cdev = &fled_cdev->led_cdev;
364 
365 	ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
366 	if (ret)
367 		return ret;
368 
369 	ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
370 	ktd2692_init_movie_current_max(&led_cfg);
371 
372 	fled_cdev->ops = &flash_ops;
373 
374 	led_cdev->max_brightness = led_cfg.max_brightness;
375 	led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
376 	led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
377 
378 	mutex_init(&led->lock);
379 
380 	platform_set_drvdata(pdev, led);
381 
382 	ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
383 	if (ret) {
384 		dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
385 		mutex_destroy(&led->lock);
386 		return ret;
387 	}
388 
389 	ktd2692_setup(led);
390 
391 	return 0;
392 }
393 
394 static int ktd2692_remove(struct platform_device *pdev)
395 {
396 	struct ktd2692_context *led = platform_get_drvdata(pdev);
397 
398 	led_classdev_flash_unregister(&led->fled_cdev);
399 
400 	mutex_destroy(&led->lock);
401 
402 	return 0;
403 }
404 
405 static const struct of_device_id ktd2692_match[] = {
406 	{ .compatible = "kinetic,ktd2692", },
407 	{ /* sentinel */ },
408 };
409 MODULE_DEVICE_TABLE(of, ktd2692_match);
410 
411 static struct platform_driver ktd2692_driver = {
412 	.driver = {
413 		.name  = "ktd2692",
414 		.of_match_table = ktd2692_match,
415 	},
416 	.probe  = ktd2692_probe,
417 	.remove = ktd2692_remove,
418 };
419 
420 module_platform_driver(ktd2692_driver);
421 
422 MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
423 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
424 MODULE_LICENSE("GPL v2");
425