aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/leds/leds-lp5521.c
blob: 4d91c08656c5c69573bc6d2e34dbaf7323039764 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
/*
 * LP5521 LED chip driver.
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/leds.h>
#include <linux/leds-lp5521.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#define LP5521_PROGRAM_LENGTH		32	/* in bytes */

#define LP5521_MAX_LEDS			3	/* Maximum number of LEDs */
#define LP5521_MAX_ENGINES		3	/* Maximum number of engines */

#define LP5521_ENG_MASK_BASE		0x30	/* 00110000 */
#define LP5521_ENG_STATUS_MASK		0x07	/* 00000111 */

#define LP5521_CMD_LOAD			0x15	/* 00010101 */
#define LP5521_CMD_RUN			0x2a	/* 00101010 */
#define LP5521_CMD_DIRECT		0x3f	/* 00111111 */
#define LP5521_CMD_DISABLED		0x00	/* 00000000 */

/* Registers */
#define LP5521_REG_ENABLE		0x00
#define LP5521_REG_OP_MODE		0x01
#define LP5521_REG_R_PWM		0x02
#define LP5521_REG_G_PWM		0x03
#define LP5521_REG_B_PWM		0x04
#define LP5521_REG_R_CURRENT		0x05
#define LP5521_REG_G_CURRENT		0x06
#define LP5521_REG_B_CURRENT		0x07
#define LP5521_REG_CONFIG		0x08
#define LP5521_REG_R_CHANNEL_PC		0x09
#define LP5521_REG_G_CHANNEL_PC		0x0A
#define LP5521_REG_B_CHANNEL_PC		0x0B
#define LP5521_REG_STATUS		0x0C
#define LP5521_REG_RESET		0x0D
#define LP5521_REG_GPO			0x0E
#define LP5521_REG_R_PROG_MEM		0x10
#define LP5521_REG_G_PROG_MEM		0x30
#define LP5521_REG_B_PROG_MEM		0x50

#define LP5521_PROG_MEM_BASE		LP5521_REG_R_PROG_MEM
#define LP5521_PROG_MEM_SIZE		0x20

/* Base register to set LED current */
#define LP5521_REG_LED_CURRENT_BASE	LP5521_REG_R_CURRENT

/* Base register to set the brightness */
#define LP5521_REG_LED_PWM_BASE		LP5521_REG_R_PWM

/* Bits in ENABLE register */
#define LP5521_MASTER_ENABLE		0x40	/* Chip master enable */
#define LP5521_LOGARITHMIC_PWM		0x80	/* Logarithmic PWM adjustment */
#define LP5521_EXEC_RUN			0x2A

/* Bits in CONFIG register */
#define LP5521_PWM_HF			0x40	/* PWM: 0 = 256Hz, 1 = 558Hz */
#define LP5521_PWRSAVE_EN		0x20	/* 1 = Power save mode */
#define LP5521_CP_MODE_OFF		0	/* Charge pump (CP) off */
#define LP5521_CP_MODE_BYPASS		8	/* CP forced to bypass mode */
#define LP5521_CP_MODE_1X5		0x10	/* CP forced to 1.5x mode */
#define LP5521_CP_MODE_AUTO		0x18	/* Automatic mode selection */
#define LP5521_R_TO_BATT		4	/* R out: 0 = CP, 1 = Vbat */
#define LP5521_CLK_SRC_EXT		0	/* Ext-clk source (CLK_32K) */
#define LP5521_CLK_INT			1	/* Internal clock */
#define LP5521_CLK_AUTO			2	/* Automatic clock selection */

/* Status */
#define LP5521_EXT_CLK_USED		0x08

struct lp5521_engine {
	int		id;
	u8		mode;
	u8		prog_page;
	u8		engine_mask;
};

struct lp5521_led {
	int			id;
	u8			chan_nr;
	u8			led_current;
	u8			max_current;
	struct led_classdev	cdev;
	struct work_struct	brightness_work;
	u8			brightness;
};

struct lp5521_chip {
	struct lp5521_platform_data *pdata;
	struct mutex		lock; /* Serialize control */
	struct i2c_client	*client;
	struct lp5521_engine	engines[LP5521_MAX_ENGINES];
	struct lp5521_led	leds[LP5521_MAX_LEDS];
	u8			num_channels;
	u8			num_leds;
};

static inline struct lp5521_led *cdev_to_led(struct led_classdev *cdev)
{
	return container_of(cdev, struct lp5521_led, cdev);
}

static inline struct lp5521_chip *engine_to_lp5521(struct lp5521_engine *engine)
{
	return container_of(engine, struct lp5521_chip,
			    engines[engine->id - 1]);
}

static inline struct lp5521_chip *led_to_lp5521(struct lp5521_led *led)
{
	return container_of(led, struct lp5521_chip,
			    leds[led->id]);
}

static void lp5521_led_brightness_work(struct work_struct *work);

static inline int lp5521_write(struct i2c_client *client, u8 reg, u8 value)
{
	return i2c_smbus_write_byte_data(client, reg, value);
}

static int lp5521_read(struct i2c_client *client, u8 reg, u8 *buf)
{
	s32 ret;

	ret = i2c_smbus_read_byte_data(client, reg);
	if (ret < 0)
		return -EIO;

	*buf = ret;
	return 0;
}

static int lp5521_set_engine_mode(struct lp5521_engine *engine, u8 mode)
{
	struct lp5521_chip *chip = engine_to_lp5521(engine);
	struct i2c_client *client = chip->client;
	int ret;
	u8 engine_state;

	/* Only transition between RUN and DIRECT mode are handled here */
	if (mode == LP5521_CMD_LOAD)
		return 0;

	if (mode == LP5521_CMD_DISABLED)
		mode = LP5521_CMD_DIRECT;

	ret = lp5521_read(client, LP5521_REG_OP_MODE, &engine_state);

	/* set mode only for this engine */
	engine_state &= ~(engine->engine_mask);
	mode &= engine->engine_mask;
	engine_state |= mode;
	ret |= lp5521_write(client, LP5521_REG_OP_MODE, engine_state);

	return ret;
}

static int lp5521_load_program(struct lp5521_engine *eng, const u8 *pattern)
{
	struct lp5521_chip *chip = engine_to_lp5521(eng);
	struct i2c_client *client = chip->client;
	int ret;
	int addr;
	u8 mode;

	/* move current engine to direct mode and remember the state */
	ret = lp5521_set_engine_mode(eng, LP5521_CMD_DIRECT);
	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
	usleep_range(1000, 2000);
	ret |= lp5521_read(client, LP5521_REG_OP_MODE, &mode);

	/* For loading, all the engines to load mode */
	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
	usleep_range(1000, 2000);
	lp5521_write(client, LP5521_REG_OP_MODE, LP5521_CMD_LOAD);
	/* Mode change requires min 500 us delay. 1 - 2 ms  with margin */
	usleep_range(1000, 2000);

	addr = LP5521_PROG_MEM_BASE + eng->prog_page * LP5521_PROG_MEM_SIZE;
	i2c_smbus_write_i2c_block_data(client,
				addr,
				LP5521_PROG_MEM_SIZE,
				pattern);

	ret |= lp5521_write(client, LP5521_REG_OP_MODE, mode);
	return ret;
}

static int lp5521_set_led_current(struct lp5521_chip *chip, int led, u8 curr)
{
	return lp5521_write(chip->client,
		    LP5521_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
		    curr);
}

static void lp5521_init_engine(struct lp5521_chip *chip)
{
	int i;
	for (i = 0; i < ARRAY_SIZE(chip->engines); i++) {
		chip->engines[i].id = i + 1;
		chip->engines[i].engine_mask = LP5521_ENG_MASK_BASE >> (i * 2);
		chip->engines[i].prog_page = i;
	}
}

static int lp5521_configure(struct i2c_client *client)
{
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	int ret;

	lp5521_init_engine(chip);

	/* Set all PWMs to direct control mode */
	ret = lp5521_write(client, LP5521_REG_OP_MODE, 0x3F);

	/* Enable auto-powersave, set charge pump to auto, red to battery */
	ret |= lp5521_write(client, LP5521_REG_CONFIG,
		LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO | LP5521_R_TO_BATT);

	/* Initialize all channels PWM to zero -> leds off */
	ret |= lp5521_write(client, LP5521_REG_R_PWM, 0);
	ret |= lp5521_write(client, LP5521_REG_G_PWM, 0);
	ret |= lp5521_write(client, LP5521_REG_B_PWM, 0);

	/* Set engines are set to run state when OP_MODE enables engines */
	ret |= lp5521_write(client, LP5521_REG_ENABLE,
			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM |
			LP5521_EXEC_RUN);
	/* enable takes 500us. 1 - 2 ms leaves some margin */
	usleep_range(1000, 2000);

	return ret;
}

static int lp5521_run_selftest(struct lp5521_chip *chip, char *buf)
{
	int ret;
	u8 status;

	ret = lp5521_read(chip->client, LP5521_REG_STATUS, &status);
	if (ret < 0)
		return ret;

	/* Check that ext clock is really in use if requested */
	if (chip->pdata && chip->pdata->clock_mode == LP5521_CLOCK_EXT)
		if  ((status & LP5521_EXT_CLK_USED) == 0)
			return -EIO;
	return 0;
}

static void lp5521_set_brightness(struct led_classdev *cdev,
			     enum led_brightness brightness)
{
	struct lp5521_led *led = cdev_to_led(cdev);
	led->brightness = (u8)brightness;
	schedule_work(&led->brightness_work);
}

static void lp5521_led_brightness_work(struct work_struct *work)
{
	struct lp5521_led *led = container_of(work,
					      struct lp5521_led,
					      brightness_work);
	struct lp5521_chip *chip = led_to_lp5521(led);
	struct i2c_client *client = chip->client;

	mutex_lock(&chip->lock);
	lp5521_write(client, LP5521_REG_LED_PWM_BASE + led->chan_nr,
		led->brightness);
	mutex_unlock(&chip->lock);
}

/* Detect the chip by setting its ENABLE register and reading it back. */
static int lp5521_detect(struct i2c_client *client)
{
	int ret;
	u8 buf;

	ret = lp5521_write(client, LP5521_REG_ENABLE,
			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM);
	if (ret)
		return ret;
	/* enable takes 500us. 1 - 2 ms leaves some margin */
	usleep_range(1000, 2000);
	ret = lp5521_read(client, LP5521_REG_ENABLE, &buf);
	if (ret)
		return ret;
	if (buf != (LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM))
		return -ENODEV;

	return 0;
}

/* Set engine mode and create appropriate sysfs attributes, if required. */
static int lp5521_set_mode(struct lp5521_engine *engine, u8 mode)
{
	int ret = 0;

	/* if in that mode already do nothing, except for run */
	if (mode == engine->mode && mode != LP5521_CMD_RUN)
		return 0;

	if (mode == LP5521_CMD_RUN) {
		ret = lp5521_set_engine_mode(engine, LP5521_CMD_RUN);
	} else if (mode == LP5521_CMD_LOAD) {
		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
		lp5521_set_engine_mode(engine, LP5521_CMD_LOAD);
	} else if (mode == LP5521_CMD_DISABLED) {
		lp5521_set_engine_mode(engine, LP5521_CMD_DISABLED);
	}

	engine->mode = mode;

	return ret;
}

static int lp5521_do_store_load(struct lp5521_engine *engine,
				const char *buf, size_t len)
{
	struct lp5521_chip *chip = engine_to_lp5521(engine);
	struct i2c_client *client = chip->client;
	int  ret, nrchars, offset = 0, i = 0;
	char c[3];
	unsigned cmd;
	u8 pattern[LP5521_PROGRAM_LENGTH] = {0};

	while ((offset < len - 1) && (i < LP5521_PROGRAM_LENGTH)) {
		/* separate sscanfs because length is working only for %s */
		ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);
		if (ret != 2)
			goto fail;
		ret = sscanf(c, "%2x", &cmd);
		if (ret != 1)
			goto fail;
		pattern[i] = (u8)cmd;

		offset += nrchars;
		i++;
	}

	/* Each instruction is 16bit long. Check that length is even */
	if (i % 2)
		goto fail;

	mutex_lock(&chip->lock);
	if (engine->mode == LP5521_CMD_LOAD)
		ret = lp5521_load_program(engine, pattern);
	else
		ret = -EINVAL;
	mutex_unlock(&chip->lock);

	if (ret) {
		dev_err(&client->dev, "failed loading pattern\n");
		return ret;
	}

	return len;
fail:
	dev_err(&client->dev, "wrong pattern format\n");
	return -EINVAL;
}

static ssize_t store_engine_load(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t len, int nr)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	return lp5521_do_store_load(&chip->engines[nr - 1], buf, len);
}

#define store_load(nr)							\
static ssize_t store_engine##nr##_load(struct device *dev,		\
				     struct device_attribute *attr,	\
				     const char *buf, size_t len)	\
{									\
	return store_engine_load(dev, attr, buf, len, nr);		\
}
store_load(1)
store_load(2)
store_load(3)

static ssize_t show_engine_mode(struct device *dev,
				struct device_attribute *attr,
				char *buf, int nr)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	switch (chip->engines[nr - 1].mode) {
	case LP5521_CMD_RUN:
		return sprintf(buf, "run\n");
	case LP5521_CMD_LOAD:
		return sprintf(buf, "load\n");
	case LP5521_CMD_DISABLED:
		return sprintf(buf, "disabled\n");
	default:
		return sprintf(buf, "disabled\n");
	}
}

#define show_mode(nr)							\
static ssize_t show_engine##nr##_mode(struct device *dev,		\
				    struct device_attribute *attr,	\
				    char *buf)				\
{									\
	return show_engine_mode(dev, attr, buf, nr);			\
}
show_mode(1)
show_mode(2)
show_mode(3)

static ssize_t store_engine_mode(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t len, int nr)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	struct lp5521_engine *engine = &chip->engines[nr - 1];
	mutex_lock(&chip->lock);

	if (!strncmp(buf, "run", 3))
		lp5521_set_mode(engine, LP5521_CMD_RUN);
	else if (!strncmp(buf, "load", 4))
		lp5521_set_mode(engine, LP5521_CMD_LOAD);
	else if (!strncmp(buf, "disabled", 8))
		lp5521_set_mode(engine, LP5521_CMD_DISABLED);

	mutex_unlock(&chip->lock);
	return len;
}

#define store_mode(nr)							\
static ssize_t store_engine##nr##_mode(struct device *dev,		\
				     struct device_attribute *attr,	\
				     const char *buf, size_t len)	\
{									\
	return store_engine_mode(dev, attr, buf, len, nr);		\
}
store_mode(1)
store_mode(2)
store_mode(3)

static ssize_t show_max_current(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct lp5521_led *led = cdev_to_led(led_cdev);

	return sprintf(buf, "%d\n", led->max_current);
}

static ssize_t show_current(struct device *dev,
			    struct device_attribute *attr,
			    char *buf)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct lp5521_led *led = cdev_to_led(led_cdev);

	return sprintf(buf, "%d\n", led->led_current);
}

static ssize_t store_current(struct device *dev,
			     struct device_attribute *attr,
			     const char *buf, size_t len)
{
	struct led_classdev *led_cdev = dev_get_drvdata(dev);
	struct lp5521_led *led = cdev_to_led(led_cdev);
	struct lp5521_chip *chip = led_to_lp5521(led);
	ssize_t ret;
	unsigned long curr;

	if (strict_strtoul(buf, 0, &curr))
		return -EINVAL;

	if (curr > led->max_current)
		return -EINVAL;

	mutex_lock(&chip->lock);
	ret = lp5521_set_led_current(chip, led->id, curr);
	mutex_unlock(&chip->lock);

	if (ret < 0)
		return ret;

	led->led_current = (u8)curr;

	return len;
}

static ssize_t lp5521_selftest(struct device *dev,
			       struct device_attribute *attr,
			       char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	int ret;

	mutex_lock(&chip->lock);
	ret = lp5521_run_selftest(chip, buf);
	mutex_unlock(&chip->lock);
	return sprintf(buf, "%s\n", ret ? "FAIL" : "OK");
}

/* led class device attributes */
static DEVICE_ATTR(led_current, S_IRUGO | S_IWUGO, show_current, store_current);
static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);

static struct attribute *lp5521_led_attributes[] = {
	&dev_attr_led_current.attr,
	&dev_attr_max_current.attr,
	NULL,
};

static struct attribute_group lp5521_led_attribute_group = {
	.attrs = lp5521_led_attributes
};

/* device attributes */
static DEVICE_ATTR(engine1_mode, S_IRUGO | S_IWUGO,
		   show_engine1_mode, store_engine1_mode);
static DEVICE_ATTR(engine2_mode, S_IRUGO | S_IWUGO,
		   show_engine2_mode, store_engine2_mode);
static DEVICE_ATTR(engine3_mode, S_IRUGO | S_IWUGO,
		   show_engine3_mode, store_engine3_mode);
static DEVICE_ATTR(engine1_load, S_IWUGO, NULL, store_engine1_load);
static DEVICE_ATTR(engine2_load, S_IWUGO, NULL, store_engine2_load);
static DEVICE_ATTR(engine3_load, S_IWUGO, NULL, store_engine3_load);
static DEVICE_ATTR(selftest, S_IRUGO, lp5521_selftest, NULL);

static struct attribute *lp5521_attributes[] = {
	&dev_attr_engine1_mode.attr,
	&dev_attr_engine2_mode.attr,
	&dev_attr_engine3_mode.attr,
	&dev_attr_selftest.attr,
	&dev_attr_engine1_load.attr,
	&dev_attr_engine2_load.attr,
	&dev_attr_engine3_load.attr,
	NULL
};

static const struct attribute_group lp5521_group = {
	.attrs = lp5521_attributes,
};

static int lp5521_register_sysfs(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	return sysfs_create_group(&dev->kobj, &lp5521_group);
}

static void lp5521_unregister_sysfs(struct i2c_client *client)
{
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	struct device *dev = &client->dev;
	int i;

	sysfs_remove_group(&dev->kobj, &lp5521_group);

	for (i = 0; i < chip->num_leds; i++)
		sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
				&lp5521_led_attribute_group);
}

static int __init lp5521_init_led(struct lp5521_led *led,
				struct i2c_client *client,
				int chan, struct lp5521_platform_data *pdata)
{
	struct device *dev = &client->dev;
	char name[32];
	int res;

	if (chan >= LP5521_MAX_LEDS)
		return -EINVAL;

	if (pdata->led_config[chan].led_current == 0)
		return 0;

	led->led_current = pdata->led_config[chan].led_current;
	led->max_current = pdata->led_config[chan].max_current;
	led->chan_nr = pdata->led_config[chan].chan_nr;

	if (led->chan_nr >= LP5521_MAX_LEDS) {
		dev_err(dev, "Use channel numbers between 0 and %d\n",
			LP5521_MAX_LEDS - 1);
		return -EINVAL;
	}

	snprintf(name, sizeof(name), "%s:channel%d", client->name, chan);
	led->cdev.brightness_set = lp5521_set_brightness;
	led->cdev.name = name;
	res = led_classdev_register(dev, &led->cdev);
	if (res < 0) {
		dev_err(dev, "couldn't register led on channel %d\n", chan);
		return res;
	}

	res = sysfs_create_group(&led->cdev.dev->kobj,
			&lp5521_led_attribute_group);
	if (res < 0) {
		dev_err(dev, "couldn't register current attribute\n");
		led_classdev_unregister(&led->cdev);
		return res;
	}
	return 0;
}

static int lp5521_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct lp5521_chip		*chip;
	struct lp5521_platform_data	*pdata;
	int ret, i, led;

	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	i2c_set_clientdata(client, chip);
	chip->client = client;

	pdata = client->dev.platform_data;

	if (!pdata) {
		dev_err(&client->dev, "no platform data\n");
		ret = -EINVAL;
		goto fail1;
	}

	mutex_init(&chip->lock);

	chip->pdata   = pdata;

	if (pdata->setup_resources) {
		ret = pdata->setup_resources();
		if (ret < 0)
			goto fail1;
	}

	if (pdata->enable) {
		pdata->enable(0);
		usleep_range(1000, 2000); /* Keep enable down at least 1ms */
		pdata->enable(1);
		usleep_range(1000, 2000); /* 500us abs min. */
	}

	lp5521_write(client, LP5521_REG_RESET, 0xff);
	usleep_range(10000, 20000); /*
				     * Exact value is not available. 10 - 20ms
				     * appears to be enough for reset.
				     */
	ret = lp5521_detect(client);

	if (ret) {
		dev_err(&client->dev, "Chip not found\n");
		goto fail2;
	}

	dev_info(&client->dev, "%s programmable led chip found\n", id->name);

	ret = lp5521_configure(client);
	if (ret < 0) {
		dev_err(&client->dev, "error configuring chip\n");
		goto fail2;
	}

	/* Initialize leds */
	chip->num_channels = pdata->num_channels;
	chip->num_leds = 0;
	led = 0;
	for (i = 0; i < pdata->num_channels; i++) {
		/* Do not initialize channels that are not connected */
		if (pdata->led_config[i].led_current == 0)
			continue;

		ret = lp5521_init_led(&chip->leds[led], client, i, pdata);
		if (ret) {
			dev_err(&client->dev, "error initializing leds\n");
			goto fail3;
		}
		chip->num_leds++;

		chip->leds[led].id = led;
		/* Set initial LED current */
		lp5521_set_led_current(chip, led,
				chip->leds[led].led_current);

		INIT_WORK(&(chip->leds[led].brightness_work),
			lp5521_led_brightness_work);

		led++;
	}

	ret = lp5521_register_sysfs(client);
	if (ret) {
		dev_err(&client->dev, "registering sysfs failed\n");
		goto fail3;
	}
	return ret;
fail3:
	for (i = 0; i < chip->num_leds; i++) {
		led_classdev_unregister(&chip->leds[i].cdev);
		cancel_work_sync(&chip->leds[i].brightness_work);
	}
fail2:
	if (pdata->enable)
		pdata->enable(0);
	if (pdata->release_resources)
		pdata->release_resources();
fail1:
	kfree(chip);
	return ret;
}

static int lp5521_remove(struct i2c_client *client)
{
	struct lp5521_chip *chip = i2c_get_clientdata(client);
	int i;

	lp5521_unregister_sysfs(client);

	for (i = 0; i < chip->num_leds; i++) {
		led_classdev_unregister(&chip->leds[i].cdev);
		cancel_work_sync(&chip->leds[i].brightness_work);
	}

	if (chip->pdata->enable)
		chip->pdata->enable(0);
	if (chip->pdata->release_resources)
		chip->pdata->release_resources();
	kfree(chip);
	return 0;
}

static const struct i2c_device_id lp5521_id[] = {
	{ "lp5521", 0 }, /* Three channel chip */
	{ }
};
MODULE_DEVICE_TABLE(i2c, lp5521_id);

static struct i2c_driver lp5521_driver = {
	.driver = {
		.name	= "lp5521",
	},
	.probe		= lp5521_probe,
	.remove		= lp5521_remove,
	.id_table	= lp5521_id,
};

static int __init lp5521_init(void)
{
	int ret;

	ret = i2c_add_driver(&lp5521_driver);

	if (ret < 0)
		printk(KERN_ALERT "Adding lp5521 driver failed\n");

	return ret;
}

static void __exit lp5521_exit(void)
{
	i2c_del_driver(&lp5521_driver);
}

module_init(lp5521_init);
module_exit(lp5521_exit);

MODULE_AUTHOR("Mathias Nyman, Yuri Zaporozhets, Samu Onkalo");
MODULE_DESCRIPTION("LP5521 LED engine");
MODULE_LICENSE("GPL v2");