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
fled_cdev_to_led(struct led_classdev_flash * fled_cdev)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
ktd2692_expresswire_start(struct ktd2692_context * led)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
ktd2692_expresswire_reset(struct ktd2692_context * led)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
ktd2692_expresswire_end(struct ktd2692_context * led)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
ktd2692_expresswire_set_bit(struct ktd2692_context * led,bool bit)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
ktd2692_expresswire_write(struct ktd2692_context * led,u8 value)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
ktd2692_led_brightness_set(struct led_classdev * led_cdev,enum led_brightness brightness)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
ktd2692_led_flash_strobe_set(struct led_classdev_flash * fled_cdev,bool state)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
ktd2692_led_flash_timeout_set(struct led_classdev_flash * fled_cdev,u32 timeout)210 static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
211 u32 timeout)
212 {
213 return 0;
214 }
215
ktd2692_init_movie_current_max(struct ktd2692_led_config_data * cfg)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
ktd2692_init_flash_timeout(struct led_classdev_flash * fled_cdev,struct ktd2692_led_config_data * cfg)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
ktd2692_setup(struct ktd2692_context * led)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
ktd2692_parse_dt(struct ktd2692_context * led,struct device * dev,struct ktd2692_led_config_data * cfg)259 static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
260 struct ktd2692_led_config_data *cfg)
261 {
262 struct device_node *np = dev_of_node(dev);
263 struct device_node *child_node;
264 int ret;
265
266 if (!dev_of_node(dev))
267 return -ENXIO;
268
269 led->ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
270 ret = PTR_ERR_OR_ZERO(led->ctrl_gpio);
271 if (ret) {
272 dev_err(dev, "cannot get ctrl-gpios %d\n", ret);
273 return ret;
274 }
275
276 led->aux_gpio = devm_gpiod_get(dev, "aux", GPIOD_ASIS);
277 ret = PTR_ERR_OR_ZERO(led->aux_gpio);
278 if (ret) {
279 dev_err(dev, "cannot get aux-gpios %d\n", ret);
280 return ret;
281 }
282
283 led->regulator = devm_regulator_get(dev, "vin");
284 if (IS_ERR(led->regulator))
285 led->regulator = NULL;
286
287 if (led->regulator) {
288 ret = regulator_enable(led->regulator);
289 if (ret)
290 dev_err(dev, "Failed to enable supply: %d\n", ret);
291 }
292
293 child_node = of_get_next_available_child(np, NULL);
294 if (!child_node) {
295 dev_err(dev, "No DT child node found for connected LED.\n");
296 return -EINVAL;
297 }
298
299 led->fled_cdev.led_cdev.name =
300 of_get_property(child_node, "label", NULL) ? : child_node->name;
301
302 ret = of_property_read_u32(child_node, "led-max-microamp",
303 &cfg->movie_max_microamp);
304 if (ret) {
305 dev_err(dev, "failed to parse led-max-microamp\n");
306 goto err_parse_dt;
307 }
308
309 ret = of_property_read_u32(child_node, "flash-max-microamp",
310 &cfg->flash_max_microamp);
311 if (ret) {
312 dev_err(dev, "failed to parse flash-max-microamp\n");
313 goto err_parse_dt;
314 }
315
316 ret = of_property_read_u32(child_node, "flash-max-timeout-us",
317 &cfg->flash_max_timeout);
318 if (ret) {
319 dev_err(dev, "failed to parse flash-max-timeout-us\n");
320 goto err_parse_dt;
321 }
322
323 err_parse_dt:
324 of_node_put(child_node);
325 return ret;
326 }
327
328 static const struct led_flash_ops flash_ops = {
329 .strobe_set = ktd2692_led_flash_strobe_set,
330 .timeout_set = ktd2692_led_flash_timeout_set,
331 };
332
ktd2692_probe(struct platform_device * pdev)333 static int ktd2692_probe(struct platform_device *pdev)
334 {
335 struct ktd2692_context *led;
336 struct led_classdev *led_cdev;
337 struct led_classdev_flash *fled_cdev;
338 struct ktd2692_led_config_data led_cfg;
339 int ret;
340
341 led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
342 if (!led)
343 return -ENOMEM;
344
345 fled_cdev = &led->fled_cdev;
346 led_cdev = &fled_cdev->led_cdev;
347
348 ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
349 if (ret)
350 return ret;
351
352 ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
353 ktd2692_init_movie_current_max(&led_cfg);
354
355 fled_cdev->ops = &flash_ops;
356
357 led_cdev->max_brightness = led_cfg.max_brightness;
358 led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
359 led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;
360
361 mutex_init(&led->lock);
362
363 platform_set_drvdata(pdev, led);
364
365 ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
366 if (ret) {
367 dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
368 mutex_destroy(&led->lock);
369 return ret;
370 }
371
372 ktd2692_setup(led);
373
374 return 0;
375 }
376
ktd2692_remove(struct platform_device * pdev)377 static int ktd2692_remove(struct platform_device *pdev)
378 {
379 struct ktd2692_context *led = platform_get_drvdata(pdev);
380 int ret;
381
382 led_classdev_flash_unregister(&led->fled_cdev);
383
384 if (led->regulator) {
385 ret = regulator_disable(led->regulator);
386 if (ret)
387 dev_err(&pdev->dev,
388 "Failed to disable supply: %d\n", ret);
389 }
390
391 mutex_destroy(&led->lock);
392
393 return 0;
394 }
395
396 static const struct of_device_id ktd2692_match[] = {
397 { .compatible = "kinetic,ktd2692", },
398 { /* sentinel */ },
399 };
400 MODULE_DEVICE_TABLE(of, ktd2692_match);
401
402 static struct platform_driver ktd2692_driver = {
403 .driver = {
404 .name = "ktd2692",
405 .of_match_table = ktd2692_match,
406 },
407 .probe = ktd2692_probe,
408 .remove = ktd2692_remove,
409 };
410
411 module_platform_driver(ktd2692_driver);
412
413 MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
414 MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
415 MODULE_LICENSE("GPL v2");
416
