xref: /linux/drivers/leds/leds-blinkm.c (revision 0da908c291070d89482f6211dbe81d4d43c3f7cb)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  leds-blinkm.c
4  *  (c) Jan-Simon Möller (dl9pf@gmx.de)
5  */
6 
7 #include <linux/module.h>
8 #include <linux/slab.h>
9 #include <linux/jiffies.h>
10 #include <linux/i2c.h>
11 #include <linux/err.h>
12 #include <linux/mutex.h>
13 #include <linux/sysfs.h>
14 #include <linux/printk.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/leds.h>
17 #include <linux/delay.h>
18 
19 /* Addresses to scan - BlinkM is on 0x09 by default*/
20 static const unsigned short normal_i2c[] = { 0x09, I2C_CLIENT_END };
21 
22 static int blinkm_transfer_hw(struct i2c_client *client, int cmd);
23 static int blinkm_test_run(struct i2c_client *client);
24 
25 struct blinkm_led {
26 	struct i2c_client *i2c_client;
27 	struct led_classdev led_cdev;
28 	int id;
29 };
30 
31 #define cdev_to_blmled(c)          container_of(c, struct blinkm_led, led_cdev)
32 
33 struct blinkm_data {
34 	struct i2c_client *i2c_client;
35 	struct mutex update_lock;
36 	/* used for led class interface */
37 	struct blinkm_led blinkm_leds[3];
38 	/* used for "blinkm" sysfs interface */
39 	u8 red;			/* color red */
40 	u8 green;		/* color green */
41 	u8 blue;		/* color blue */
42 	/* next values to use for transfer */
43 	u8 next_red;			/* color red */
44 	u8 next_green;		/* color green */
45 	u8 next_blue;		/* color blue */
46 	/* internal use */
47 	u8 args[7];		/* set of args for transmission */
48 	u8 i2c_addr;		/* i2c addr */
49 	u8 fw_ver;		/* firmware version */
50 	/* used, but not from userspace */
51 	u8 hue;			/* HSB  hue */
52 	u8 saturation;		/* HSB  saturation */
53 	u8 brightness;		/* HSB  brightness */
54 	u8 next_hue;			/* HSB  hue */
55 	u8 next_saturation;		/* HSB  saturation */
56 	u8 next_brightness;		/* HSB  brightness */
57 	/* currently unused / todo */
58 	u8 fade_speed;		/* fade speed     1 - 255 */
59 	s8 time_adjust;		/* time adjust -128 - 127 */
60 	u8 fade:1;		/* fade on = 1, off = 0 */
61 	u8 rand:1;		/* rand fade mode on = 1 */
62 	u8 script_id;		/* script ID */
63 	u8 script_repeats;	/* repeats of script */
64 	u8 script_startline;	/* line to start */
65 };
66 
67 /* Colors */
68 #define RED   0
69 #define GREEN 1
70 #define BLUE  2
71 
72 /* mapping command names to cmd chars - see datasheet */
73 #define BLM_GO_RGB            0
74 #define BLM_FADE_RGB          1
75 #define BLM_FADE_HSB          2
76 #define BLM_FADE_RAND_RGB     3
77 #define BLM_FADE_RAND_HSB     4
78 #define BLM_PLAY_SCRIPT       5
79 #define BLM_STOP_SCRIPT       6
80 #define BLM_SET_FADE_SPEED    7
81 #define BLM_SET_TIME_ADJ      8
82 #define BLM_GET_CUR_RGB       9
83 #define BLM_WRITE_SCRIPT_LINE 10
84 #define BLM_READ_SCRIPT_LINE  11
85 #define BLM_SET_SCRIPT_LR     12	/* Length & Repeats */
86 #define BLM_SET_ADDR          13
87 #define BLM_GET_ADDR          14
88 #define BLM_GET_FW_VER        15
89 #define BLM_SET_STARTUP_PARAM 16
90 
91 /* BlinkM Commands
92  *  as extracted out of the datasheet:
93  *
94  *  cmdchar = command (ascii)
95  *  cmdbyte = command in hex
96  *  nr_args = number of arguments (to send)
97  *  nr_ret  = number of return values (to read)
98  *  dir = direction (0 = read, 1 = write, 2 = both)
99  *
100  */
101 static const struct {
102 	char cmdchar;
103 	u8 cmdbyte;
104 	u8 nr_args;
105 	u8 nr_ret;
106 	u8 dir:2;
107 } blinkm_cmds[17] = {
108   /* cmdchar, cmdbyte, nr_args, nr_ret,  dir */
109 	{ 'n', 0x6e, 3, 0, 1},
110 	{ 'c', 0x63, 3, 0, 1},
111 	{ 'h', 0x68, 3, 0, 1},
112 	{ 'C', 0x43, 3, 0, 1},
113 	{ 'H', 0x48, 3, 0, 1},
114 	{ 'p', 0x70, 3, 0, 1},
115 	{ 'o', 0x6f, 0, 0, 1},
116 	{ 'f', 0x66, 1, 0, 1},
117 	{ 't', 0x74, 1, 0, 1},
118 	{ 'g', 0x67, 0, 3, 0},
119 	{ 'W', 0x57, 7, 0, 1},
120 	{ 'R', 0x52, 2, 5, 2},
121 	{ 'L', 0x4c, 3, 0, 1},
122 	{ 'A', 0x41, 4, 0, 1},
123 	{ 'a', 0x61, 0, 1, 0},
124 	{ 'Z', 0x5a, 0, 1, 0},
125 	{ 'B', 0x42, 5, 0, 1},
126 };
127 
128 static ssize_t show_color_common(struct device *dev, char *buf, int color)
129 {
130 	struct i2c_client *client;
131 	struct blinkm_data *data;
132 	int ret;
133 
134 	client = to_i2c_client(dev);
135 	data = i2c_get_clientdata(client);
136 
137 	ret = blinkm_transfer_hw(client, BLM_GET_CUR_RGB);
138 	if (ret < 0)
139 		return ret;
140 	switch (color) {
141 	case RED:
142 		return sysfs_emit(buf, "%02X\n", data->red);
143 	case GREEN:
144 		return sysfs_emit(buf, "%02X\n", data->green);
145 	case BLUE:
146 		return sysfs_emit(buf, "%02X\n", data->blue);
147 	default:
148 		return -EINVAL;
149 	}
150 	return -EINVAL;
151 }
152 
153 static int store_color_common(struct device *dev, const char *buf, int color)
154 {
155 	struct i2c_client *client;
156 	struct blinkm_data *data;
157 	int ret;
158 	u8 value;
159 
160 	client = to_i2c_client(dev);
161 	data = i2c_get_clientdata(client);
162 
163 	ret = kstrtou8(buf, 10, &value);
164 	if (ret < 0) {
165 		dev_err(dev, "BlinkM: value too large!\n");
166 		return ret;
167 	}
168 
169 	switch (color) {
170 	case RED:
171 		data->next_red = value;
172 		break;
173 	case GREEN:
174 		data->next_green = value;
175 		break;
176 	case BLUE:
177 		data->next_blue = value;
178 		break;
179 	default:
180 		return -EINVAL;
181 	}
182 
183 	dev_dbg(dev, "next_red = %d, next_green = %d, next_blue = %d\n",
184 			data->next_red, data->next_green, data->next_blue);
185 
186 	/* if mode ... */
187 	ret = blinkm_transfer_hw(client, BLM_GO_RGB);
188 	if (ret < 0) {
189 		dev_err(dev, "BlinkM: can't set RGB\n");
190 		return ret;
191 	}
192 	return 0;
193 }
194 
195 static ssize_t red_show(struct device *dev, struct device_attribute *attr,
196 			char *buf)
197 {
198 	return show_color_common(dev, buf, RED);
199 }
200 
201 static ssize_t red_store(struct device *dev, struct device_attribute *attr,
202 			 const char *buf, size_t count)
203 {
204 	int ret;
205 
206 	ret = store_color_common(dev, buf, RED);
207 	if (ret < 0)
208 		return ret;
209 	return count;
210 }
211 
212 static DEVICE_ATTR_RW(red);
213 
214 static ssize_t green_show(struct device *dev, struct device_attribute *attr,
215 			  char *buf)
216 {
217 	return show_color_common(dev, buf, GREEN);
218 }
219 
220 static ssize_t green_store(struct device *dev, struct device_attribute *attr,
221 			   const char *buf, size_t count)
222 {
223 
224 	int ret;
225 
226 	ret = store_color_common(dev, buf, GREEN);
227 	if (ret < 0)
228 		return ret;
229 	return count;
230 }
231 
232 static DEVICE_ATTR_RW(green);
233 
234 static ssize_t blue_show(struct device *dev, struct device_attribute *attr,
235 			 char *buf)
236 {
237 	return show_color_common(dev, buf, BLUE);
238 }
239 
240 static ssize_t blue_store(struct device *dev, struct device_attribute *attr,
241 			  const char *buf, size_t count)
242 {
243 	int ret;
244 
245 	ret = store_color_common(dev, buf, BLUE);
246 	if (ret < 0)
247 		return ret;
248 	return count;
249 }
250 
251 static DEVICE_ATTR_RW(blue);
252 
253 static ssize_t test_show(struct device *dev, struct device_attribute *attr,
254 			 char *buf)
255 {
256 	return sysfs_emit(buf,
257 			 "#Write into test to start test sequence!#\n");
258 }
259 
260 static ssize_t test_store(struct device *dev, struct device_attribute *attr,
261 			  const char *buf, size_t count)
262 {
263 
264 	struct i2c_client *client;
265 	int ret;
266 	client = to_i2c_client(dev);
267 
268 	/*test */
269 	ret = blinkm_test_run(client);
270 	if (ret < 0)
271 		return ret;
272 
273 	return count;
274 }
275 
276 static DEVICE_ATTR_RW(test);
277 
278 /* TODO: HSB, fade, timeadj, script ... */
279 
280 static struct attribute *blinkm_attrs[] = {
281 	&dev_attr_red.attr,
282 	&dev_attr_green.attr,
283 	&dev_attr_blue.attr,
284 	&dev_attr_test.attr,
285 	NULL,
286 };
287 
288 static const struct attribute_group blinkm_group = {
289 	.name = "blinkm",
290 	.attrs = blinkm_attrs,
291 };
292 
293 static int blinkm_write(struct i2c_client *client, int cmd, u8 *arg)
294 {
295 	int result;
296 	int i;
297 	int arglen = blinkm_cmds[cmd].nr_args;
298 	/* write out cmd to blinkm - always / default step */
299 	result = i2c_smbus_write_byte(client, blinkm_cmds[cmd].cmdbyte);
300 	if (result < 0)
301 		return result;
302 	/* no args to write out */
303 	if (arglen == 0)
304 		return 0;
305 
306 	for (i = 0; i < arglen; i++) {
307 		/* repeat for arglen */
308 		result = i2c_smbus_write_byte(client, arg[i]);
309 		if (result < 0)
310 			return result;
311 	}
312 	return 0;
313 }
314 
315 static int blinkm_read(struct i2c_client *client, int cmd, u8 *arg)
316 {
317 	int result;
318 	int i;
319 	int retlen = blinkm_cmds[cmd].nr_ret;
320 	for (i = 0; i < retlen; i++) {
321 		/* repeat for retlen */
322 		result = i2c_smbus_read_byte(client);
323 		if (result < 0)
324 			return result;
325 		arg[i] = result;
326 	}
327 
328 	return 0;
329 }
330 
331 static int blinkm_transfer_hw(struct i2c_client *client, int cmd)
332 {
333 	/* the protocol is simple but non-standard:
334 	 * e.g.  cmd 'g' (= 0x67) for "get device address"
335 	 * - which defaults to 0x09 - would be the sequence:
336 	 *   a) write 0x67 to the device (byte write)
337 	 *   b) read the value (0x09) back right after (byte read)
338 	 *
339 	 * Watch out for "unfinished" sequences (i.e. not enough reads
340 	 * or writes after a command. It will make the blinkM misbehave.
341 	 * Sequence is key here.
342 	 */
343 
344 	/* args / return are in private data struct */
345 	struct blinkm_data *data = i2c_get_clientdata(client);
346 
347 	/* We start hardware transfers which are not to be
348 	 * mixed with other commands. Aquire a lock now. */
349 	if (mutex_lock_interruptible(&data->update_lock) < 0)
350 		return -EAGAIN;
351 
352 	/* switch cmd - usually write before reads */
353 	switch (cmd) {
354 	case BLM_FADE_RAND_RGB:
355 	case BLM_GO_RGB:
356 	case BLM_FADE_RGB:
357 		data->args[0] = data->next_red;
358 		data->args[1] = data->next_green;
359 		data->args[2] = data->next_blue;
360 		blinkm_write(client, cmd, data->args);
361 		data->red = data->args[0];
362 		data->green = data->args[1];
363 		data->blue = data->args[2];
364 		break;
365 	case BLM_FADE_HSB:
366 	case BLM_FADE_RAND_HSB:
367 		data->args[0] = data->next_hue;
368 		data->args[1] = data->next_saturation;
369 		data->args[2] = data->next_brightness;
370 		blinkm_write(client, cmd, data->args);
371 		data->hue = data->next_hue;
372 		data->saturation = data->next_saturation;
373 		data->brightness = data->next_brightness;
374 		break;
375 	case BLM_PLAY_SCRIPT:
376 		data->args[0] = data->script_id;
377 		data->args[1] = data->script_repeats;
378 		data->args[2] = data->script_startline;
379 		blinkm_write(client, cmd, data->args);
380 		break;
381 	case BLM_STOP_SCRIPT:
382 		blinkm_write(client, cmd, NULL);
383 		break;
384 	case BLM_GET_CUR_RGB:
385 		data->args[0] = data->red;
386 		data->args[1] = data->green;
387 		data->args[2] = data->blue;
388 		blinkm_write(client, cmd, NULL);
389 		blinkm_read(client, cmd, data->args);
390 		data->red = data->args[0];
391 		data->green = data->args[1];
392 		data->blue = data->args[2];
393 		break;
394 	case BLM_GET_ADDR:
395 		data->args[0] = data->i2c_addr;
396 		blinkm_write(client, cmd, NULL);
397 		blinkm_read(client, cmd, data->args);
398 		data->i2c_addr = data->args[0];
399 		break;
400 	case BLM_SET_TIME_ADJ:
401 	case BLM_SET_FADE_SPEED:
402 	case BLM_READ_SCRIPT_LINE:
403 	case BLM_WRITE_SCRIPT_LINE:
404 	case BLM_SET_SCRIPT_LR:
405 	case BLM_SET_ADDR:
406 	case BLM_GET_FW_VER:
407 	case BLM_SET_STARTUP_PARAM:
408 		dev_err(&client->dev,
409 				"BlinkM: cmd %d not implemented yet.\n", cmd);
410 		break;
411 	default:
412 		dev_err(&client->dev, "BlinkM: unknown command %d\n", cmd);
413 		mutex_unlock(&data->update_lock);
414 		return -EINVAL;
415 	}			/* end switch(cmd) */
416 
417 	/* transfers done, unlock */
418 	mutex_unlock(&data->update_lock);
419 	return 0;
420 }
421 
422 static int blinkm_led_common_set(struct led_classdev *led_cdev,
423 				 enum led_brightness value, int color)
424 {
425 	/* led_brightness is 0, 127 or 255 - we just use it here as-is */
426 	struct blinkm_led *led = cdev_to_blmled(led_cdev);
427 	struct blinkm_data *data = i2c_get_clientdata(led->i2c_client);
428 
429 	switch (color) {
430 	case RED:
431 		/* bail out if there's no change */
432 		if (data->next_red == (u8) value)
433 			return 0;
434 		data->next_red = (u8) value;
435 		break;
436 	case GREEN:
437 		/* bail out if there's no change */
438 		if (data->next_green == (u8) value)
439 			return 0;
440 		data->next_green = (u8) value;
441 		break;
442 	case BLUE:
443 		/* bail out if there's no change */
444 		if (data->next_blue == (u8) value)
445 			return 0;
446 		data->next_blue = (u8) value;
447 		break;
448 
449 	default:
450 		dev_err(&led->i2c_client->dev, "BlinkM: unknown color.\n");
451 		return -EINVAL;
452 	}
453 
454 	blinkm_transfer_hw(led->i2c_client, BLM_GO_RGB);
455 	dev_dbg(&led->i2c_client->dev,
456 			"# DONE # next_red = %d, next_green = %d,"
457 			" next_blue = %d\n",
458 			data->next_red, data->next_green,
459 			data->next_blue);
460 	return 0;
461 }
462 
463 static int blinkm_led_red_set(struct led_classdev *led_cdev,
464 			       enum led_brightness value)
465 {
466 	return blinkm_led_common_set(led_cdev, value, RED);
467 }
468 
469 static int blinkm_led_green_set(struct led_classdev *led_cdev,
470 				 enum led_brightness value)
471 {
472 	return blinkm_led_common_set(led_cdev, value, GREEN);
473 }
474 
475 static int blinkm_led_blue_set(struct led_classdev *led_cdev,
476 				enum led_brightness value)
477 {
478 	return blinkm_led_common_set(led_cdev, value, BLUE);
479 }
480 
481 static void blinkm_init_hw(struct i2c_client *client)
482 {
483 	blinkm_transfer_hw(client, BLM_STOP_SCRIPT);
484 	blinkm_transfer_hw(client, BLM_GO_RGB);
485 }
486 
487 static int blinkm_test_run(struct i2c_client *client)
488 {
489 	int ret;
490 	struct blinkm_data *data = i2c_get_clientdata(client);
491 
492 	data->next_red = 0x01;
493 	data->next_green = 0x05;
494 	data->next_blue = 0x10;
495 	ret = blinkm_transfer_hw(client, BLM_GO_RGB);
496 	if (ret < 0)
497 		return ret;
498 	msleep(2000);
499 
500 	data->next_red = 0x25;
501 	data->next_green = 0x10;
502 	data->next_blue = 0x31;
503 	ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
504 	if (ret < 0)
505 		return ret;
506 	msleep(2000);
507 
508 	data->next_hue = 0x50;
509 	data->next_saturation = 0x10;
510 	data->next_brightness = 0x20;
511 	ret = blinkm_transfer_hw(client, BLM_FADE_HSB);
512 	if (ret < 0)
513 		return ret;
514 	msleep(2000);
515 
516 	return 0;
517 }
518 
519 /* Return 0 if detection is successful, -ENODEV otherwise */
520 static int blinkm_detect(struct i2c_client *client, struct i2c_board_info *info)
521 {
522 	struct i2c_adapter *adapter = client->adapter;
523 	int ret;
524 	int count = 99;
525 	u8 tmpargs[7];
526 
527 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
528 				     | I2C_FUNC_SMBUS_WORD_DATA
529 				     | I2C_FUNC_SMBUS_WRITE_BYTE))
530 		return -ENODEV;
531 
532 	/* Now, we do the remaining detection. Simple for now. */
533 	/* We might need more guards to protect other i2c slaves */
534 
535 	/* make sure the blinkM is balanced (read/writes) */
536 	while (count > 0) {
537 		ret = blinkm_write(client, BLM_GET_ADDR, NULL);
538 		if (ret)
539 			return ret;
540 		usleep_range(5000, 10000);
541 		ret = blinkm_read(client, BLM_GET_ADDR, tmpargs);
542 		if (ret)
543 			return ret;
544 		usleep_range(5000, 10000);
545 		if (tmpargs[0] == 0x09)
546 			count = 0;
547 		count--;
548 	}
549 
550 	/* Step 1: Read BlinkM address back  -  cmd_char 'a' */
551 	ret = blinkm_write(client, BLM_GET_ADDR, NULL);
552 	if (ret < 0)
553 		return ret;
554 	usleep_range(20000, 30000);	/* allow a small delay */
555 	ret = blinkm_read(client, BLM_GET_ADDR, tmpargs);
556 	if (ret < 0)
557 		return ret;
558 
559 	if (tmpargs[0] != 0x09) {
560 		dev_err(&client->dev, "enodev DEV ADDR = 0x%02X\n", tmpargs[0]);
561 		return -ENODEV;
562 	}
563 
564 	strlcpy(info->type, "blinkm", I2C_NAME_SIZE);
565 	return 0;
566 }
567 
568 static int blinkm_probe(struct i2c_client *client,
569 			const struct i2c_device_id *id)
570 {
571 	struct blinkm_data *data;
572 	struct blinkm_led *led[3];
573 	int err, i;
574 	char blinkm_led_name[28];
575 
576 	data = devm_kzalloc(&client->dev,
577 			sizeof(struct blinkm_data), GFP_KERNEL);
578 	if (!data) {
579 		err = -ENOMEM;
580 		goto exit;
581 	}
582 
583 	data->i2c_addr = 0x08;
584 	/* i2c addr  - use fake addr of 0x08 initially (real is 0x09) */
585 	data->fw_ver = 0xfe;
586 	/* firmware version - use fake until we read real value
587 	 * (currently broken - BlinkM confused!) */
588 	data->script_id = 0x01;
589 	data->i2c_client = client;
590 
591 	i2c_set_clientdata(client, data);
592 	mutex_init(&data->update_lock);
593 
594 	/* Register sysfs hooks */
595 	err = sysfs_create_group(&client->dev.kobj, &blinkm_group);
596 	if (err < 0) {
597 		dev_err(&client->dev, "couldn't register sysfs group\n");
598 		goto exit;
599 	}
600 
601 	for (i = 0; i < 3; i++) {
602 		/* RED = 0, GREEN = 1, BLUE = 2 */
603 		led[i] = &data->blinkm_leds[i];
604 		led[i]->i2c_client = client;
605 		led[i]->id = i;
606 		led[i]->led_cdev.max_brightness = 255;
607 		led[i]->led_cdev.flags = LED_CORE_SUSPENDRESUME;
608 		switch (i) {
609 		case RED:
610 			snprintf(blinkm_led_name, sizeof(blinkm_led_name),
611 					 "blinkm-%d-%d-red",
612 					 client->adapter->nr,
613 					 client->addr);
614 			led[i]->led_cdev.name = blinkm_led_name;
615 			led[i]->led_cdev.brightness_set_blocking =
616 							blinkm_led_red_set;
617 			err = led_classdev_register(&client->dev,
618 						    &led[i]->led_cdev);
619 			if (err < 0) {
620 				dev_err(&client->dev,
621 					"couldn't register LED %s\n",
622 					led[i]->led_cdev.name);
623 				goto failred;
624 			}
625 			break;
626 		case GREEN:
627 			snprintf(blinkm_led_name, sizeof(blinkm_led_name),
628 					 "blinkm-%d-%d-green",
629 					 client->adapter->nr,
630 					 client->addr);
631 			led[i]->led_cdev.name = blinkm_led_name;
632 			led[i]->led_cdev.brightness_set_blocking =
633 							blinkm_led_green_set;
634 			err = led_classdev_register(&client->dev,
635 						    &led[i]->led_cdev);
636 			if (err < 0) {
637 				dev_err(&client->dev,
638 					"couldn't register LED %s\n",
639 					led[i]->led_cdev.name);
640 				goto failgreen;
641 			}
642 			break;
643 		case BLUE:
644 			snprintf(blinkm_led_name, sizeof(blinkm_led_name),
645 					 "blinkm-%d-%d-blue",
646 					 client->adapter->nr,
647 					 client->addr);
648 			led[i]->led_cdev.name = blinkm_led_name;
649 			led[i]->led_cdev.brightness_set_blocking =
650 							blinkm_led_blue_set;
651 			err = led_classdev_register(&client->dev,
652 						    &led[i]->led_cdev);
653 			if (err < 0) {
654 				dev_err(&client->dev,
655 					"couldn't register LED %s\n",
656 					led[i]->led_cdev.name);
657 				goto failblue;
658 			}
659 			break;
660 		}		/* end switch */
661 	}			/* end for */
662 
663 	/* Initialize the blinkm */
664 	blinkm_init_hw(client);
665 
666 	return 0;
667 
668 failblue:
669 	led_classdev_unregister(&led[GREEN]->led_cdev);
670 
671 failgreen:
672 	led_classdev_unregister(&led[RED]->led_cdev);
673 
674 failred:
675 	sysfs_remove_group(&client->dev.kobj, &blinkm_group);
676 exit:
677 	return err;
678 }
679 
680 static void blinkm_remove(struct i2c_client *client)
681 {
682 	struct blinkm_data *data = i2c_get_clientdata(client);
683 	int ret = 0;
684 	int i;
685 
686 	/* make sure no workqueue entries are pending */
687 	for (i = 0; i < 3; i++)
688 		led_classdev_unregister(&data->blinkm_leds[i].led_cdev);
689 
690 	/* reset rgb */
691 	data->next_red = 0x00;
692 	data->next_green = 0x00;
693 	data->next_blue = 0x00;
694 	ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
695 	if (ret < 0)
696 		dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");
697 
698 	/* reset hsb */
699 	data->next_hue = 0x00;
700 	data->next_saturation = 0x00;
701 	data->next_brightness = 0x00;
702 	ret = blinkm_transfer_hw(client, BLM_FADE_HSB);
703 	if (ret < 0)
704 		dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");
705 
706 	/* red fade to off */
707 	data->next_red = 0xff;
708 	ret = blinkm_transfer_hw(client, BLM_GO_RGB);
709 	if (ret < 0)
710 		dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");
711 
712 	/* off */
713 	data->next_red = 0x00;
714 	ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
715 	if (ret < 0)
716 		dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");
717 
718 	sysfs_remove_group(&client->dev.kobj, &blinkm_group);
719 }
720 
721 static const struct i2c_device_id blinkm_id[] = {
722 	{"blinkm", 0},
723 	{}
724 };
725 
726 MODULE_DEVICE_TABLE(i2c, blinkm_id);
727 
728   /* This is the driver that will be inserted */
729 static struct i2c_driver blinkm_driver = {
730 	.class = I2C_CLASS_HWMON,
731 	.driver = {
732 		   .name = "blinkm",
733 		   },
734 	.probe = blinkm_probe,
735 	.remove = blinkm_remove,
736 	.id_table = blinkm_id,
737 	.detect = blinkm_detect,
738 	.address_list = normal_i2c,
739 };
740 
741 module_i2c_driver(blinkm_driver);
742 
743 MODULE_AUTHOR("Jan-Simon Moeller <dl9pf@gmx.de>");
744 MODULE_DESCRIPTION("BlinkM RGB LED driver");
745 MODULE_LICENSE("GPL");
746 
747