1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Backlight driver for Analog Devices ADP8860 Backlight Devices
4  *
5  * Copyright 2009-2010 Analog Devices Inc.
6  */
7 
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/errno.h>
11 #include <linux/pm.h>
12 #include <linux/platform_device.h>
13 #include <linux/i2c.h>
14 #include <linux/fb.h>
15 #include <linux/backlight.h>
16 #include <linux/leds.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 
20 #include <linux/platform_data/adp8860.h>
21 #define ADP8860_EXT_FEATURES
22 #define ADP8860_USE_LEDS
23 
24 #define ADP8860_MFDVID 0x00 /* Manufacturer and device ID */
25 #define ADP8860_MDCR 0x01 /* Device mode and status */
26 #define ADP8860_MDCR2 0x02 /* Device mode and Status Register 2 */
27 #define ADP8860_INTR_EN 0x03 /* Interrupts enable */
28 #define ADP8860_CFGR 0x04 /* Configuration register */
29 #define ADP8860_BLSEN 0x05 /* Sink enable backlight or independent */
30 #define ADP8860_BLOFF 0x06 /* Backlight off timeout */
31 #define ADP8860_BLDIM 0x07 /* Backlight dim timeout */
32 #define ADP8860_BLFR 0x08 /* Backlight fade in and out rates */
33 #define ADP8860_BLMX1 0x09 /* Backlight (Brightness Level 1-daylight) maximum current */
34 #define ADP8860_BLDM1 0x0A /* Backlight (Brightness Level 1-daylight) dim current */
35 #define ADP8860_BLMX2 0x0B /* Backlight (Brightness Level 2-office) maximum current */
36 #define ADP8860_BLDM2 0x0C /* Backlight (Brightness Level 2-office) dim current */
37 #define ADP8860_BLMX3 0x0D /* Backlight (Brightness Level 3-dark) maximum current */
38 #define ADP8860_BLDM3 0x0E /* Backlight (Brightness Level 3-dark) dim current */
39 #define ADP8860_ISCFR 0x0F /* Independent sink current fade control register */
40 #define ADP8860_ISCC 0x10 /* Independent sink current control register */
41 #define ADP8860_ISCT1 0x11 /* Independent Sink Current Timer Register LED[7:5] */
42 #define ADP8860_ISCT2 0x12 /* Independent Sink Current Timer Register LED[4:1] */
43 #define ADP8860_ISCF 0x13 /* Independent sink current fade register */
44 #define ADP8860_ISC7 0x14 /* Independent Sink Current LED7 */
45 #define ADP8860_ISC6 0x15 /* Independent Sink Current LED6 */
46 #define ADP8860_ISC5 0x16 /* Independent Sink Current LED5 */
47 #define ADP8860_ISC4 0x17 /* Independent Sink Current LED4 */
48 #define ADP8860_ISC3 0x18 /* Independent Sink Current LED3 */
49 #define ADP8860_ISC2 0x19 /* Independent Sink Current LED2 */
50 #define ADP8860_ISC1 0x1A /* Independent Sink Current LED1 */
51 #define ADP8860_CCFG 0x1B /* Comparator configuration */
52 #define ADP8860_CCFG2 0x1C /* Second comparator configuration */
53 #define ADP8860_L2_TRP 0x1D /* L2 comparator reference */
54 #define ADP8860_L2_HYS 0x1E /* L2 hysteresis */
55 #define ADP8860_L3_TRP 0x1F /* L3 comparator reference */
56 #define ADP8860_L3_HYS 0x20 /* L3 hysteresis */
57 #define ADP8860_PH1LEVL 0x21 /* First phototransistor ambient light level-low byte register */
58 #define ADP8860_PH1LEVH 0x22 /* First phototransistor ambient light level-high byte register */
59 #define ADP8860_PH2LEVL 0x23 /* Second phototransistor ambient light level-low byte register */
60 #define ADP8860_PH2LEVH 0x24 /* Second phototransistor ambient light level-high byte register */
61 
62 #define ADP8860_MANUFID		0x0  /* Analog Devices ADP8860 Manufacturer ID */
63 #define ADP8861_MANUFID		0x4  /* Analog Devices ADP8861 Manufacturer ID */
64 #define ADP8863_MANUFID		0x2  /* Analog Devices ADP8863 Manufacturer ID */
65 
66 #define ADP8860_DEVID(x)	((x) & 0xF)
67 #define ADP8860_MANID(x)	((x) >> 4)
68 
69 /* MDCR Device mode and status */
70 #define INT_CFG			(1 << 6)
71 #define NSTBY			(1 << 5)
72 #define DIM_EN			(1 << 4)
73 #define GDWN_DIS		(1 << 3)
74 #define SIS_EN			(1 << 2)
75 #define CMP_AUTOEN		(1 << 1)
76 #define BLEN			(1 << 0)
77 
78 /* ADP8860_CCFG Main ALS comparator level enable */
79 #define L3_EN			(1 << 1)
80 #define L2_EN			(1 << 0)
81 
82 #define CFGR_BLV_SHIFT		3
83 #define CFGR_BLV_MASK		0x3
84 #define ADP8860_FLAG_LED_MASK	0xFF
85 
86 #define FADE_VAL(in, out)	((0xF & (in)) | ((0xF & (out)) << 4))
87 #define BL_CFGR_VAL(law, blv)	((((blv) & CFGR_BLV_MASK) << CFGR_BLV_SHIFT) | ((0x3 & (law)) << 1))
88 #define ALS_CCFG_VAL(filt)	((0x7 & filt) << 5)
89 
90 enum {
91 	adp8860,
92 	adp8861,
93 	adp8863
94 };
95 
96 struct adp8860_led {
97 	struct led_classdev	cdev;
98 	struct work_struct	work;
99 	struct i2c_client	*client;
100 	enum led_brightness	new_brightness;
101 	int			id;
102 	int			flags;
103 };
104 
105 struct adp8860_bl {
106 	struct i2c_client *client;
107 	struct backlight_device *bl;
108 	struct adp8860_led *led;
109 	struct adp8860_backlight_platform_data *pdata;
110 	struct mutex lock;
111 	unsigned long cached_daylight_max;
112 	int id;
113 	int revid;
114 	int current_brightness;
115 	unsigned en_ambl_sens:1;
116 	unsigned gdwn_dis:1;
117 };
118 
119 static int adp8860_read(struct i2c_client *client, int reg, uint8_t *val)
120 {
121 	int ret;
122 
123 	ret = i2c_smbus_read_byte_data(client, reg);
124 	if (ret < 0) {
125 		dev_err(&client->dev, "failed reading at 0x%02x\n", reg);
126 		return ret;
127 	}
128 
129 	*val = (uint8_t)ret;
130 	return 0;
131 }
132 
133 static int adp8860_write(struct i2c_client *client, u8 reg, u8 val)
134 {
135 	return i2c_smbus_write_byte_data(client, reg, val);
136 }
137 
138 static int adp8860_set_bits(struct i2c_client *client, int reg, uint8_t bit_mask)
139 {
140 	struct adp8860_bl *data = i2c_get_clientdata(client);
141 	uint8_t reg_val;
142 	int ret;
143 
144 	mutex_lock(&data->lock);
145 
146 	ret = adp8860_read(client, reg, &reg_val);
147 
148 	if (!ret && ((reg_val & bit_mask) != bit_mask)) {
149 		reg_val |= bit_mask;
150 		ret = adp8860_write(client, reg, reg_val);
151 	}
152 
153 	mutex_unlock(&data->lock);
154 	return ret;
155 }
156 
157 static int adp8860_clr_bits(struct i2c_client *client, int reg, uint8_t bit_mask)
158 {
159 	struct adp8860_bl *data = i2c_get_clientdata(client);
160 	uint8_t reg_val;
161 	int ret;
162 
163 	mutex_lock(&data->lock);
164 
165 	ret = adp8860_read(client, reg, &reg_val);
166 
167 	if (!ret && (reg_val & bit_mask)) {
168 		reg_val &= ~bit_mask;
169 		ret = adp8860_write(client, reg, reg_val);
170 	}
171 
172 	mutex_unlock(&data->lock);
173 	return ret;
174 }
175 
176 /*
177  * Independent sink / LED
178  */
179 #if defined(ADP8860_USE_LEDS)
180 static void adp8860_led_work(struct work_struct *work)
181 {
182 	struct adp8860_led *led = container_of(work, struct adp8860_led, work);
183 
184 	adp8860_write(led->client, ADP8860_ISC1 - led->id + 1,
185 			 led->new_brightness >> 1);
186 }
187 
188 static void adp8860_led_set(struct led_classdev *led_cdev,
189 			   enum led_brightness value)
190 {
191 	struct adp8860_led *led;
192 
193 	led = container_of(led_cdev, struct adp8860_led, cdev);
194 	led->new_brightness = value;
195 	schedule_work(&led->work);
196 }
197 
198 static int adp8860_led_setup(struct adp8860_led *led)
199 {
200 	struct i2c_client *client = led->client;
201 	int ret = 0;
202 
203 	ret = adp8860_write(client, ADP8860_ISC1 - led->id + 1, 0);
204 	ret |= adp8860_set_bits(client, ADP8860_ISCC, 1 << (led->id - 1));
205 
206 	if (led->id > 4)
207 		ret |= adp8860_set_bits(client, ADP8860_ISCT1,
208 				(led->flags & 0x3) << ((led->id - 5) * 2));
209 	else
210 		ret |= adp8860_set_bits(client, ADP8860_ISCT2,
211 				(led->flags & 0x3) << ((led->id - 1) * 2));
212 
213 	return ret;
214 }
215 
216 static int adp8860_led_probe(struct i2c_client *client)
217 {
218 	struct adp8860_backlight_platform_data *pdata =
219 		dev_get_platdata(&client->dev);
220 	struct adp8860_bl *data = i2c_get_clientdata(client);
221 	struct adp8860_led *led, *led_dat;
222 	struct led_info *cur_led;
223 	int ret, i;
224 
225 	led = devm_kcalloc(&client->dev, pdata->num_leds, sizeof(*led),
226 				GFP_KERNEL);
227 	if (led == NULL)
228 		return -ENOMEM;
229 
230 	ret = adp8860_write(client, ADP8860_ISCFR, pdata->led_fade_law);
231 	ret = adp8860_write(client, ADP8860_ISCT1,
232 			(pdata->led_on_time & 0x3) << 6);
233 	ret |= adp8860_write(client, ADP8860_ISCF,
234 			FADE_VAL(pdata->led_fade_in, pdata->led_fade_out));
235 
236 	if (ret) {
237 		dev_err(&client->dev, "failed to write\n");
238 		return ret;
239 	}
240 
241 	for (i = 0; i < pdata->num_leds; ++i) {
242 		cur_led = &pdata->leds[i];
243 		led_dat = &led[i];
244 
245 		led_dat->id = cur_led->flags & ADP8860_FLAG_LED_MASK;
246 
247 		if (led_dat->id > 7 || led_dat->id < 1) {
248 			dev_err(&client->dev, "Invalid LED ID %d\n",
249 				led_dat->id);
250 			ret = -EINVAL;
251 			goto err;
252 		}
253 
254 		if (pdata->bl_led_assign & (1 << (led_dat->id - 1))) {
255 			dev_err(&client->dev, "LED %d used by Backlight\n",
256 				led_dat->id);
257 			ret = -EBUSY;
258 			goto err;
259 		}
260 
261 		led_dat->cdev.name = cur_led->name;
262 		led_dat->cdev.default_trigger = cur_led->default_trigger;
263 		led_dat->cdev.brightness_set = adp8860_led_set;
264 		led_dat->cdev.brightness = LED_OFF;
265 		led_dat->flags = cur_led->flags >> FLAG_OFFT_SHIFT;
266 		led_dat->client = client;
267 		led_dat->new_brightness = LED_OFF;
268 		INIT_WORK(&led_dat->work, adp8860_led_work);
269 
270 		ret = led_classdev_register(&client->dev, &led_dat->cdev);
271 		if (ret) {
272 			dev_err(&client->dev, "failed to register LED %d\n",
273 				led_dat->id);
274 			goto err;
275 		}
276 
277 		ret = adp8860_led_setup(led_dat);
278 		if (ret) {
279 			dev_err(&client->dev, "failed to write\n");
280 			i++;
281 			goto err;
282 		}
283 	}
284 
285 	data->led = led;
286 
287 	return 0;
288 
289  err:
290 	for (i = i - 1; i >= 0; --i) {
291 		led_classdev_unregister(&led[i].cdev);
292 		cancel_work_sync(&led[i].work);
293 	}
294 
295 	return ret;
296 }
297 
298 static int adp8860_led_remove(struct i2c_client *client)
299 {
300 	struct adp8860_backlight_platform_data *pdata =
301 		dev_get_platdata(&client->dev);
302 	struct adp8860_bl *data = i2c_get_clientdata(client);
303 	int i;
304 
305 	for (i = 0; i < pdata->num_leds; i++) {
306 		led_classdev_unregister(&data->led[i].cdev);
307 		cancel_work_sync(&data->led[i].work);
308 	}
309 
310 	return 0;
311 }
312 #else
313 static int adp8860_led_probe(struct i2c_client *client)
314 {
315 	return 0;
316 }
317 
318 static int adp8860_led_remove(struct i2c_client *client)
319 {
320 	return 0;
321 }
322 #endif
323 
324 static int adp8860_bl_set(struct backlight_device *bl, int brightness)
325 {
326 	struct adp8860_bl *data = bl_get_data(bl);
327 	struct i2c_client *client = data->client;
328 	int ret = 0;
329 
330 	if (data->en_ambl_sens) {
331 		if ((brightness > 0) && (brightness < ADP8860_MAX_BRIGHTNESS)) {
332 			/* Disable Ambient Light auto adjust */
333 			ret |= adp8860_clr_bits(client, ADP8860_MDCR,
334 					CMP_AUTOEN);
335 			ret |= adp8860_write(client, ADP8860_BLMX1, brightness);
336 		} else {
337 			/*
338 			 * MAX_BRIGHTNESS -> Enable Ambient Light auto adjust
339 			 * restore daylight l1 sysfs brightness
340 			 */
341 			ret |= adp8860_write(client, ADP8860_BLMX1,
342 					 data->cached_daylight_max);
343 			ret |= adp8860_set_bits(client, ADP8860_MDCR,
344 					 CMP_AUTOEN);
345 		}
346 	} else
347 		ret |= adp8860_write(client, ADP8860_BLMX1, brightness);
348 
349 	if (data->current_brightness && brightness == 0)
350 		ret |= adp8860_set_bits(client,
351 				ADP8860_MDCR, DIM_EN);
352 	else if (data->current_brightness == 0 && brightness)
353 		ret |= adp8860_clr_bits(client,
354 				ADP8860_MDCR, DIM_EN);
355 
356 	if (!ret)
357 		data->current_brightness = brightness;
358 
359 	return ret;
360 }
361 
362 static int adp8860_bl_update_status(struct backlight_device *bl)
363 {
364 	return adp8860_bl_set(bl, backlight_get_brightness(bl));
365 }
366 
367 static int adp8860_bl_get_brightness(struct backlight_device *bl)
368 {
369 	struct adp8860_bl *data = bl_get_data(bl);
370 
371 	return data->current_brightness;
372 }
373 
374 static const struct backlight_ops adp8860_bl_ops = {
375 	.update_status	= adp8860_bl_update_status,
376 	.get_brightness	= adp8860_bl_get_brightness,
377 };
378 
379 static int adp8860_bl_setup(struct backlight_device *bl)
380 {
381 	struct adp8860_bl *data = bl_get_data(bl);
382 	struct i2c_client *client = data->client;
383 	struct adp8860_backlight_platform_data *pdata = data->pdata;
384 	int ret = 0;
385 
386 	ret |= adp8860_write(client, ADP8860_BLSEN, ~pdata->bl_led_assign);
387 	ret |= adp8860_write(client, ADP8860_BLMX1, pdata->l1_daylight_max);
388 	ret |= adp8860_write(client, ADP8860_BLDM1, pdata->l1_daylight_dim);
389 
390 	if (data->en_ambl_sens) {
391 		data->cached_daylight_max = pdata->l1_daylight_max;
392 		ret |= adp8860_write(client, ADP8860_BLMX2,
393 						pdata->l2_office_max);
394 		ret |= adp8860_write(client, ADP8860_BLDM2,
395 						pdata->l2_office_dim);
396 		ret |= adp8860_write(client, ADP8860_BLMX3,
397 						pdata->l3_dark_max);
398 		ret |= adp8860_write(client, ADP8860_BLDM3,
399 						pdata->l3_dark_dim);
400 
401 		ret |= adp8860_write(client, ADP8860_L2_TRP, pdata->l2_trip);
402 		ret |= adp8860_write(client, ADP8860_L2_HYS, pdata->l2_hyst);
403 		ret |= adp8860_write(client, ADP8860_L3_TRP, pdata->l3_trip);
404 		ret |= adp8860_write(client, ADP8860_L3_HYS, pdata->l3_hyst);
405 		ret |= adp8860_write(client, ADP8860_CCFG, L2_EN | L3_EN |
406 						ALS_CCFG_VAL(pdata->abml_filt));
407 	}
408 
409 	ret |= adp8860_write(client, ADP8860_CFGR,
410 			BL_CFGR_VAL(pdata->bl_fade_law, 0));
411 
412 	ret |= adp8860_write(client, ADP8860_BLFR, FADE_VAL(pdata->bl_fade_in,
413 			pdata->bl_fade_out));
414 
415 	ret |= adp8860_set_bits(client, ADP8860_MDCR, BLEN | DIM_EN | NSTBY |
416 			(data->gdwn_dis ? GDWN_DIS : 0));
417 
418 	return ret;
419 }
420 
421 static ssize_t adp8860_show(struct device *dev, char *buf, int reg)
422 {
423 	struct adp8860_bl *data = dev_get_drvdata(dev);
424 	int error;
425 	uint8_t reg_val;
426 
427 	mutex_lock(&data->lock);
428 	error = adp8860_read(data->client, reg, &reg_val);
429 	mutex_unlock(&data->lock);
430 
431 	if (error < 0)
432 		return error;
433 
434 	return sprintf(buf, "%u\n", reg_val);
435 }
436 
437 static ssize_t adp8860_store(struct device *dev, const char *buf,
438 			 size_t count, int reg)
439 {
440 	struct adp8860_bl *data = dev_get_drvdata(dev);
441 	unsigned long val;
442 	int ret;
443 
444 	ret = kstrtoul(buf, 10, &val);
445 	if (ret)
446 		return ret;
447 
448 	mutex_lock(&data->lock);
449 	adp8860_write(data->client, reg, val);
450 	mutex_unlock(&data->lock);
451 
452 	return count;
453 }
454 
455 static ssize_t adp8860_bl_l3_dark_max_show(struct device *dev,
456 				     struct device_attribute *attr, char *buf)
457 {
458 	return adp8860_show(dev, buf, ADP8860_BLMX3);
459 }
460 
461 static ssize_t adp8860_bl_l3_dark_max_store(struct device *dev,
462 		struct device_attribute *attr, const char *buf, size_t count)
463 {
464 	return adp8860_store(dev, buf, count, ADP8860_BLMX3);
465 }
466 
467 static DEVICE_ATTR(l3_dark_max, 0664, adp8860_bl_l3_dark_max_show,
468 			adp8860_bl_l3_dark_max_store);
469 
470 static ssize_t adp8860_bl_l2_office_max_show(struct device *dev,
471 		struct device_attribute *attr, char *buf)
472 {
473 	return adp8860_show(dev, buf, ADP8860_BLMX2);
474 }
475 
476 static ssize_t adp8860_bl_l2_office_max_store(struct device *dev,
477 		struct device_attribute *attr, const char *buf, size_t count)
478 {
479 	return adp8860_store(dev, buf, count, ADP8860_BLMX2);
480 }
481 static DEVICE_ATTR(l2_office_max, 0664, adp8860_bl_l2_office_max_show,
482 			adp8860_bl_l2_office_max_store);
483 
484 static ssize_t adp8860_bl_l1_daylight_max_show(struct device *dev,
485 			struct device_attribute *attr, char *buf)
486 {
487 	return adp8860_show(dev, buf, ADP8860_BLMX1);
488 }
489 
490 static ssize_t adp8860_bl_l1_daylight_max_store(struct device *dev,
491 		struct device_attribute *attr, const char *buf, size_t count)
492 {
493 	struct adp8860_bl *data = dev_get_drvdata(dev);
494 	int ret = kstrtoul(buf, 10, &data->cached_daylight_max);
495 
496 	if (ret)
497 		return ret;
498 
499 	return adp8860_store(dev, buf, count, ADP8860_BLMX1);
500 }
501 static DEVICE_ATTR(l1_daylight_max, 0664, adp8860_bl_l1_daylight_max_show,
502 			adp8860_bl_l1_daylight_max_store);
503 
504 static ssize_t adp8860_bl_l3_dark_dim_show(struct device *dev,
505 			struct device_attribute *attr, char *buf)
506 {
507 	return adp8860_show(dev, buf, ADP8860_BLDM3);
508 }
509 
510 static ssize_t adp8860_bl_l3_dark_dim_store(struct device *dev,
511 				     struct device_attribute *attr,
512 				     const char *buf, size_t count)
513 {
514 	return adp8860_store(dev, buf, count, ADP8860_BLDM3);
515 }
516 static DEVICE_ATTR(l3_dark_dim, 0664, adp8860_bl_l3_dark_dim_show,
517 			adp8860_bl_l3_dark_dim_store);
518 
519 static ssize_t adp8860_bl_l2_office_dim_show(struct device *dev,
520 			struct device_attribute *attr, char *buf)
521 {
522 	return adp8860_show(dev, buf, ADP8860_BLDM2);
523 }
524 
525 static ssize_t adp8860_bl_l2_office_dim_store(struct device *dev,
526 				     struct device_attribute *attr,
527 				     const char *buf, size_t count)
528 {
529 	return adp8860_store(dev, buf, count, ADP8860_BLDM2);
530 }
531 static DEVICE_ATTR(l2_office_dim, 0664, adp8860_bl_l2_office_dim_show,
532 			adp8860_bl_l2_office_dim_store);
533 
534 static ssize_t adp8860_bl_l1_daylight_dim_show(struct device *dev,
535 				     struct device_attribute *attr, char *buf)
536 {
537 	return adp8860_show(dev, buf, ADP8860_BLDM1);
538 }
539 
540 static ssize_t adp8860_bl_l1_daylight_dim_store(struct device *dev,
541 				     struct device_attribute *attr,
542 				     const char *buf, size_t count)
543 {
544 	return adp8860_store(dev, buf, count, ADP8860_BLDM1);
545 }
546 static DEVICE_ATTR(l1_daylight_dim, 0664, adp8860_bl_l1_daylight_dim_show,
547 			adp8860_bl_l1_daylight_dim_store);
548 
549 #ifdef ADP8860_EXT_FEATURES
550 static ssize_t adp8860_bl_ambient_light_level_show(struct device *dev,
551 				     struct device_attribute *attr, char *buf)
552 {
553 	struct adp8860_bl *data = dev_get_drvdata(dev);
554 	int error;
555 	uint8_t reg_val;
556 	uint16_t ret_val;
557 
558 	mutex_lock(&data->lock);
559 	error = adp8860_read(data->client, ADP8860_PH1LEVL, &reg_val);
560 	if (!error) {
561 		ret_val = reg_val;
562 		error = adp8860_read(data->client, ADP8860_PH1LEVH, &reg_val);
563 	}
564 	mutex_unlock(&data->lock);
565 
566 	if (error)
567 		return error;
568 
569 	/* Return 13-bit conversion value for the first light sensor */
570 	ret_val += (reg_val & 0x1F) << 8;
571 
572 	return sprintf(buf, "%u\n", ret_val);
573 }
574 static DEVICE_ATTR(ambient_light_level, 0444,
575 		adp8860_bl_ambient_light_level_show, NULL);
576 
577 static ssize_t adp8860_bl_ambient_light_zone_show(struct device *dev,
578 				     struct device_attribute *attr, char *buf)
579 {
580 	struct adp8860_bl *data = dev_get_drvdata(dev);
581 	int error;
582 	uint8_t reg_val;
583 
584 	mutex_lock(&data->lock);
585 	error = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
586 	mutex_unlock(&data->lock);
587 
588 	if (error < 0)
589 		return error;
590 
591 	return sprintf(buf, "%u\n",
592 		((reg_val >> CFGR_BLV_SHIFT) & CFGR_BLV_MASK) + 1);
593 }
594 
595 static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
596 				     struct device_attribute *attr,
597 				     const char *buf, size_t count)
598 {
599 	struct adp8860_bl *data = dev_get_drvdata(dev);
600 	unsigned long val;
601 	uint8_t reg_val;
602 	int ret;
603 
604 	ret = kstrtoul(buf, 10, &val);
605 	if (ret)
606 		return ret;
607 
608 	if (val == 0) {
609 		/* Enable automatic ambient light sensing */
610 		adp8860_set_bits(data->client, ADP8860_MDCR, CMP_AUTOEN);
611 	} else if ((val > 0) && (val <= 3)) {
612 		/* Disable automatic ambient light sensing */
613 		adp8860_clr_bits(data->client, ADP8860_MDCR, CMP_AUTOEN);
614 
615 		/* Set user supplied ambient light zone */
616 		mutex_lock(&data->lock);
617 		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
618 		if (!ret) {
619 			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
620 			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
621 			adp8860_write(data->client, ADP8860_CFGR, reg_val);
622 		}
623 		mutex_unlock(&data->lock);
624 	}
625 
626 	return count;
627 }
628 static DEVICE_ATTR(ambient_light_zone, 0664,
629 		adp8860_bl_ambient_light_zone_show,
630 		adp8860_bl_ambient_light_zone_store);
631 #endif
632 
633 static struct attribute *adp8860_bl_attributes[] = {
634 	&dev_attr_l3_dark_max.attr,
635 	&dev_attr_l3_dark_dim.attr,
636 	&dev_attr_l2_office_max.attr,
637 	&dev_attr_l2_office_dim.attr,
638 	&dev_attr_l1_daylight_max.attr,
639 	&dev_attr_l1_daylight_dim.attr,
640 #ifdef ADP8860_EXT_FEATURES
641 	&dev_attr_ambient_light_level.attr,
642 	&dev_attr_ambient_light_zone.attr,
643 #endif
644 	NULL
645 };
646 
647 static const struct attribute_group adp8860_bl_attr_group = {
648 	.attrs = adp8860_bl_attributes,
649 };
650 
651 static int adp8860_probe(struct i2c_client *client)
652 {
653 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
654 	struct backlight_device *bl;
655 	struct adp8860_bl *data;
656 	struct adp8860_backlight_platform_data *pdata =
657 		dev_get_platdata(&client->dev);
658 	struct backlight_properties props;
659 	uint8_t reg_val;
660 	int ret;
661 
662 	if (!i2c_check_functionality(client->adapter,
663 					I2C_FUNC_SMBUS_BYTE_DATA)) {
664 		dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
665 		return -EIO;
666 	}
667 
668 	if (!pdata) {
669 		dev_err(&client->dev, "no platform data?\n");
670 		return -EINVAL;
671 	}
672 
673 	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
674 	if (data == NULL)
675 		return -ENOMEM;
676 
677 	ret = adp8860_read(client, ADP8860_MFDVID, &reg_val);
678 	if (ret < 0)
679 		return ret;
680 
681 	switch (ADP8860_MANID(reg_val)) {
682 	case ADP8863_MANUFID:
683 		data->gdwn_dis = !!pdata->gdwn_dis;
684 		fallthrough;
685 	case ADP8860_MANUFID:
686 		data->en_ambl_sens = !!pdata->en_ambl_sens;
687 		break;
688 	case ADP8861_MANUFID:
689 		data->gdwn_dis = !!pdata->gdwn_dis;
690 		break;
691 	default:
692 		dev_err(&client->dev, "failed to probe\n");
693 		return -ENODEV;
694 	}
695 
696 	/* It's confirmed that the DEVID field is actually a REVID */
697 
698 	data->revid = ADP8860_DEVID(reg_val);
699 	data->client = client;
700 	data->pdata = pdata;
701 	data->id = id->driver_data;
702 	data->current_brightness = 0;
703 	i2c_set_clientdata(client, data);
704 
705 	memset(&props, 0, sizeof(props));
706 	props.type = BACKLIGHT_RAW;
707 	props.max_brightness = ADP8860_MAX_BRIGHTNESS;
708 
709 	mutex_init(&data->lock);
710 
711 	bl = devm_backlight_device_register(&client->dev,
712 				dev_driver_string(&client->dev),
713 				&client->dev, data, &adp8860_bl_ops, &props);
714 	if (IS_ERR(bl)) {
715 		dev_err(&client->dev, "failed to register backlight\n");
716 		return PTR_ERR(bl);
717 	}
718 
719 	bl->props.brightness = ADP8860_MAX_BRIGHTNESS;
720 
721 	data->bl = bl;
722 
723 	if (data->en_ambl_sens)
724 		ret = sysfs_create_group(&bl->dev.kobj,
725 			&adp8860_bl_attr_group);
726 
727 	if (ret) {
728 		dev_err(&client->dev, "failed to register sysfs\n");
729 		return ret;
730 	}
731 
732 	ret = adp8860_bl_setup(bl);
733 	if (ret) {
734 		ret = -EIO;
735 		goto out;
736 	}
737 
738 	backlight_update_status(bl);
739 
740 	dev_info(&client->dev, "%s Rev.%d Backlight\n",
741 		client->name, data->revid);
742 
743 	if (pdata->num_leds)
744 		adp8860_led_probe(client);
745 
746 	return 0;
747 
748 out:
749 	if (data->en_ambl_sens)
750 		sysfs_remove_group(&data->bl->dev.kobj,
751 			&adp8860_bl_attr_group);
752 
753 	return ret;
754 }
755 
756 static void adp8860_remove(struct i2c_client *client)
757 {
758 	struct adp8860_bl *data = i2c_get_clientdata(client);
759 
760 	adp8860_clr_bits(client, ADP8860_MDCR, NSTBY);
761 
762 	if (data->led)
763 		adp8860_led_remove(client);
764 
765 	if (data->en_ambl_sens)
766 		sysfs_remove_group(&data->bl->dev.kobj,
767 			&adp8860_bl_attr_group);
768 }
769 
770 #ifdef CONFIG_PM_SLEEP
771 static int adp8860_i2c_suspend(struct device *dev)
772 {
773 	struct i2c_client *client = to_i2c_client(dev);
774 
775 	adp8860_clr_bits(client, ADP8860_MDCR, NSTBY);
776 
777 	return 0;
778 }
779 
780 static int adp8860_i2c_resume(struct device *dev)
781 {
782 	struct i2c_client *client = to_i2c_client(dev);
783 
784 	adp8860_set_bits(client, ADP8860_MDCR, NSTBY | BLEN);
785 
786 	return 0;
787 }
788 #endif
789 
790 static SIMPLE_DEV_PM_OPS(adp8860_i2c_pm_ops, adp8860_i2c_suspend,
791 			adp8860_i2c_resume);
792 
793 static const struct i2c_device_id adp8860_id[] = {
794 	{ "adp8860", adp8860 },
795 	{ "adp8861", adp8861 },
796 	{ "adp8863", adp8863 },
797 	{ }
798 };
799 MODULE_DEVICE_TABLE(i2c, adp8860_id);
800 
801 static struct i2c_driver adp8860_driver = {
802 	.driver = {
803 		.name	= KBUILD_MODNAME,
804 		.pm	= &adp8860_i2c_pm_ops,
805 	},
806 	.probe = adp8860_probe,
807 	.remove = adp8860_remove,
808 	.id_table = adp8860_id,
809 };
810 
811 module_i2c_driver(adp8860_driver);
812 
813 MODULE_LICENSE("GPL v2");
814 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
815 MODULE_DESCRIPTION("ADP8860 Backlight driver");
816