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
55 enum ktd2692_bitset {
56 KTD2692_LOW = 0,
57 KTD2692_HIGH,
58 };
59
60 /* Movie / Flash Mode Control */
61 enum ktd2692_led_mode {
62 KTD2692_MODE_DISABLE = 0, /* default */
63 KTD2692_MODE_MOVIE,
64 KTD2692_MODE_FLASH,
65 };
66
67 struct 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
78 struct 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
fled_cdev_to_led(struct led_classdev_flash * fled_cdev)94 static 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
ktd2692_expresswire_start(struct ktd2692_context * led)100 static 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
ktd2692_expresswire_reset(struct ktd2692_context * led)106 static 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
ktd2692_expresswire_end(struct ktd2692_context * led)112 static 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
ktd2692_expresswire_set_bit(struct ktd2692_context * led,bool bit)120 static 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
ktd2692_expresswire_write(struct ktd2692_context * led,u8 value)151 static 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
ktd2692_brightness_set(struct ktd2692_context * led,enum led_brightness brightness)161 static 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
ktd2692_brightness_set_work(struct work_struct * work)179 static 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
ktd2692_led_brightness_set(struct led_classdev * led_cdev,enum led_brightness brightness)187 static 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
ktd2692_led_brightness_set_sync(struct led_classdev * led_cdev,enum led_brightness brightness)197 static 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
ktd2692_led_flash_strobe_set(struct led_classdev_flash * fled_cdev,bool state)208 static 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
ktd2692_led_flash_timeout_set(struct led_classdev_flash * fled_cdev,u32 timeout)239 static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
240 u32 timeout)
241 {
242 return 0;
243 }
244
ktd2692_init_movie_current_max(struct ktd2692_led_config_data * cfg)245 static 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
ktd2692_init_flash_timeout(struct led_classdev_flash * fled_cdev,struct ktd2692_led_config_data * cfg)263 static 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
ktd2692_setup(struct ktd2692_context * led)276 static 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
ktd2692_parse_dt(struct ktd2692_context * led,struct device * dev,struct ktd2692_led_config_data * cfg)288 static 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 ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
300 if (ret) {
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 ret = PTR_ERR_OR_ZERO(led->aux_gpio);
307 if (ret) {
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
354 static 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
ktd2692_probe(struct platform_device * pdev)359 static 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
ktd2692_remove(struct platform_device * pdev)405 static 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
425 static const struct of_device_id ktd2692_match[] = {
426 { .compatible = "kinetic,ktd2692", },
427 { /* sentinel */ },
428 };
429 MODULE_DEVICE_TABLE(of, ktd2692_match);
430
431 static 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
440 module_platform_driver(ktd2692_driver);
441
442 MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
443 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
444 MODULE_LICENSE("GPL v2");
445