summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/regulator/max8973-regulator.c
blob: 5b75b7c2e3ea441c266a13c367d555b08d46077d (plain)
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
/*
 * max8973-regulator.c -- Maxim max8973
 *
 * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
 *
 * Copyright (c) 2012, NVIDIA Corporation.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
 * whether express or implied; 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., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307, USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/max8973-regulator.h>
#include <linux/regulator/of_regulator.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>

/* Register definitions */
#define MAX8973_VOUT					0x0
#define MAX8973_VOUT_DVS				0x1
#define MAX8973_CONTROL1				0x2
#define MAX8973_CONTROL2				0x3
#define MAX8973_CHIPID1					0x4
#define MAX8973_CHIPID2					0x5

#define MAX8973_MAX_VOUT_REG				2

/* MAX8973_VOUT */
#define MAX8973_VOUT_ENABLE				BIT(7)
#define MAX8973_VOUT_MASK				0x7F

/* MAX8973_VOUT_DVS */
#define MAX8973_DVS_VOUT_MASK				0x7F

/* MAX8973_CONTROL1 */
#define MAX8973_SNS_ENABLE				BIT(7)
#define MAX8973_FPWM_EN_M				BIT(6)
#define MAX8973_NFSR_ENABLE				BIT(5)
#define MAX8973_AD_ENABLE				BIT(4)
#define MAX8973_BIAS_ENABLE				BIT(3)
#define MAX8973_FREQSHIFT_9PER				BIT(2)

#define MAX8973_RAMP_12mV_PER_US			0x0
#define MAX8973_RAMP_25mV_PER_US			0x1
#define MAX8973_RAMP_50mV_PER_US			0x2
#define MAX8973_RAMP_200mV_PER_US			0x3
#define MAX8973_RAMP_MASK				0x3

/* MAX8973_CONTROL2 */
#define MAX8973_WDTMR_ENABLE				BIT(6)
#define MAX8973_DISCH_ENBABLE				BIT(5)
#define MAX8973_FT_ENABLE				BIT(4)

#define MAX8973_CKKADV_TRIP_MASK			0xC
#define MAX8973_CKKADV_TRIP_DISABLE			0xC
#define MAX8973_CKKADV_TRIP_75mV_PER_US			0x0
#define MAX8973_CKKADV_TRIP_150mV_PER_US		0x4
#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS	0x8
#define MAX8973_CONTROL_CLKADV_TRIP_MASK		0x00030000

#define MAX8973_INDUCTOR_MIN_30_PER			0x0
#define MAX8973_INDUCTOR_NOMINAL			0x1
#define MAX8973_INDUCTOR_PLUS_30_PER			0x2
#define MAX8973_INDUCTOR_PLUS_60_PER			0x3
#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK		0x00300000

#define MAX8973_MIN_VOLATGE				606250
#define MAX8973_MAX_VOLATGE				1400000
#define MAX8973_VOLATGE_STEP				6250
#define MAX8973_BUCK_N_VOLTAGE				0x80

enum device_id {
	MAX8973,
	MAX77621
};

/* Maxim 8973 chip information */
struct max8973_chip {
	struct device *dev;
	struct regulator_desc desc;
	struct regmap *regmap;
	bool enable_external_control;
	int enable_gpio;
	int dvs_gpio;
	int lru_index[MAX8973_MAX_VOUT_REG];
	int curr_vout_val[MAX8973_MAX_VOUT_REG];
	int curr_vout_reg;
	int curr_gpio_val;
	struct regulator_ops ops;
	enum device_id id;
};

/*
 * find_voltage_set_register: Find new voltage configuration register (VOUT).
 * The finding of the new VOUT register will be based on the LRU mechanism.
 * Each VOUT register will have different voltage configured . This
 * Function will look if any of the VOUT register have requested voltage set
 * or not.
 *     - If it is already there then it will make that register as most
 *       recently used and return as found so that caller need not to set
 *       the VOUT register but need to set the proper gpios to select this
 *       VOUT register.
 *     - If requested voltage is not found then it will use the least
 *       recently mechanism to get new VOUT register for new configuration
 *       and will return not_found so that caller need to set new VOUT
 *       register and then gpios (both).
 */
static bool find_voltage_set_register(struct max8973_chip *tps,
		int req_vsel, int *vout_reg, int *gpio_val)
{
	int i;
	bool found = false;
	int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
	int found_index = MAX8973_MAX_VOUT_REG - 1;

	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
		if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
			new_vout_reg = tps->lru_index[i];
			found_index = i;
			found = true;
			goto update_lru_index;
		}
	}

update_lru_index:
	for (i = found_index; i > 0; i--)
		tps->lru_index[i] = tps->lru_index[i - 1];

	tps->lru_index[0] = new_vout_reg;
	*gpio_val = new_vout_reg;
	*vout_reg = MAX8973_VOUT + new_vout_reg;
	return found;
}

static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int data;
	int ret;

	ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err = %d\n",
			max->curr_vout_reg, ret);
		return ret;
	}
	return data & MAX8973_VOUT_MASK;
}

static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
	     unsigned vsel)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	int ret;
	bool found = false;
	int vout_reg = max->curr_vout_reg;
	int gpio_val = max->curr_gpio_val;

	/*
	 * If gpios are available to select the VOUT register then least
	 * recently used register for new configuration.
	 */
	if (gpio_is_valid(max->dvs_gpio))
		found = find_voltage_set_register(max, vsel,
					&vout_reg, &gpio_val);

	if (!found) {
		ret = regmap_update_bits(max->regmap, vout_reg,
					MAX8973_VOUT_MASK, vsel);
		if (ret < 0) {
			dev_err(max->dev, "register %d update failed, err %d\n",
				 vout_reg, ret);
			return ret;
		}
		max->curr_vout_reg = vout_reg;
		max->curr_vout_val[gpio_val] = vsel;
	}

	/* Select proper VOUT register vio gpios */
	if (gpio_is_valid(max->dvs_gpio)) {
		gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
		max->curr_gpio_val = gpio_val;
	}
	return 0;
}

static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	int ret;
	int pwm;

	/* Enable force PWM mode in FAST mode only. */
	switch (mode) {
	case REGULATOR_MODE_FAST:
		pwm = MAX8973_FPWM_EN_M;
		break;

	case REGULATOR_MODE_NORMAL:
		pwm = 0;
		break;

	default:
		return -EINVAL;
	}

	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
				MAX8973_FPWM_EN_M, pwm);
	if (ret < 0)
		dev_err(max->dev, "register %d update failed, err %d\n",
				MAX8973_CONTROL1, ret);
	return ret;
}

static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int data;
	int ret;

	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err %d\n",
				MAX8973_CONTROL1, ret);
		return ret;
	}
	return (data & MAX8973_FPWM_EN_M) ?
		REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
}

static int max8973_set_ramp_delay(struct regulator_dev *rdev,
		int ramp_delay)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int control;
	int ret;
	int ret_val;

	/* Set ramp delay */
	if (ramp_delay < 25000) {
		control = MAX8973_RAMP_12mV_PER_US;
		ret_val = 12000;
	} else if (ramp_delay < 50000) {
		control = MAX8973_RAMP_25mV_PER_US;
		ret_val = 25000;
	} else if (ramp_delay < 200000) {
		control = MAX8973_RAMP_50mV_PER_US;
		ret_val = 50000;
	} else {
		control = MAX8973_RAMP_200mV_PER_US;
		ret_val = 200000;
	}

	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
			MAX8973_RAMP_MASK, control);
	if (ret < 0)
		dev_err(max->dev, "register %d update failed, %d",
				MAX8973_CONTROL1, ret);
	return ret;
}

static int max8973_set_current_limit(struct regulator_dev *rdev,
		int min_ua, int max_ua)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int val;
	int ret;

	if (max_ua <= 9000000)
		val = MAX8973_CKKADV_TRIP_75mV_PER_US;
	else if (max_ua <= 12000000)
		val = MAX8973_CKKADV_TRIP_150mV_PER_US;
	else
		val = MAX8973_CKKADV_TRIP_DISABLE;

	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL2,
			MAX8973_CKKADV_TRIP_MASK, val);
	if (ret < 0) {
		dev_err(max->dev, "register %d update failed: %d\n",
				MAX8973_CONTROL2, ret);
		return ret;
	}
	return 0;
}

static int max8973_get_current_limit(struct regulator_dev *rdev)
{
	struct max8973_chip *max = rdev_get_drvdata(rdev);
	unsigned int control2;
	int ret;

	ret = regmap_read(max->regmap, MAX8973_CONTROL2, &control2);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed: %d\n",
				MAX8973_CONTROL2, ret);
		return ret;
	}
	switch (control2 & MAX8973_CKKADV_TRIP_MASK) {
	case MAX8973_CKKADV_TRIP_DISABLE:
		return 15000000;
	case MAX8973_CKKADV_TRIP_150mV_PER_US:
		return 12000000;
	case MAX8973_CKKADV_TRIP_75mV_PER_US:
		return 9000000;
	default:
		break;
	}
	return 9000000;
}

static const struct regulator_ops max8973_dcdc_ops = {
	.get_voltage_sel	= max8973_dcdc_get_voltage_sel,
	.set_voltage_sel	= max8973_dcdc_set_voltage_sel,
	.list_voltage		= regulator_list_voltage_linear,
	.set_mode		= max8973_dcdc_set_mode,
	.get_mode		= max8973_dcdc_get_mode,
	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
	.set_ramp_delay		= max8973_set_ramp_delay,
};

static int max8973_init_dcdc(struct max8973_chip *max,
			     struct max8973_regulator_platform_data *pdata)
{
	int ret;
	uint8_t	control1 = 0;
	uint8_t control2 = 0;
	unsigned int data;

	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
	if (ret < 0) {
		dev_err(max->dev, "register %d read failed, err = %d",
				MAX8973_CONTROL1, ret);
		return ret;
	}
	control1 = data & MAX8973_RAMP_MASK;
	switch (control1) {
	case MAX8973_RAMP_12mV_PER_US:
		max->desc.ramp_delay = 12000;
		break;
	case MAX8973_RAMP_25mV_PER_US:
		max->desc.ramp_delay = 25000;
		break;
	case MAX8973_RAMP_50mV_PER_US:
		max->desc.ramp_delay = 50000;
		break;
	case MAX8973_RAMP_200mV_PER_US:
		max->desc.ramp_delay = 200000;
		break;
	}

	if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
		control1 |= MAX8973_SNS_ENABLE;

	if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
		control1 |= MAX8973_NFSR_ENABLE;

	if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
		control1 |= MAX8973_AD_ENABLE;

	if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
		control1 |= MAX8973_BIAS_ENABLE;
		max->desc.enable_time = 20;
	} else {
		max->desc.enable_time = 240;
	}

	if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
		control1 |= MAX8973_FREQSHIFT_9PER;

	if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
		control2 |= MAX8973_DISCH_ENBABLE;

	/*  Clock advance trip configuration */
	switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
	case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
		control2 |= MAX8973_CKKADV_TRIP_DISABLE;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
		control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
		break;

	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
		break;
	}

	/* Configure inductor value */
	switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
	case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
		control2 |= MAX8973_INDUCTOR_NOMINAL;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
		control2 |= MAX8973_INDUCTOR_MIN_30_PER;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
		control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
		break;

	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
		control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
		break;
	}

	ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
	if (ret < 0) {
		dev_err(max->dev, "register %d write failed, err = %d",
				MAX8973_CONTROL1, ret);
		return ret;
	}

	ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
	if (ret < 0) {
		dev_err(max->dev, "register %d write failed, err = %d",
				MAX8973_CONTROL2, ret);
		return ret;
	}

	/* If external control is enabled then disable EN bit */
	if (max->enable_external_control && (max->id == MAX8973)) {
		ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
						MAX8973_VOUT_ENABLE, 0);
		if (ret < 0)
			dev_err(max->dev, "register %d update failed, err = %d",
				MAX8973_VOUT, ret);
	}
	return ret;
}

static const struct regmap_config max8973_regmap_config = {
	.reg_bits		= 8,
	.val_bits		= 8,
	.max_register		= MAX8973_CHIPID2,
	.cache_type		= REGCACHE_RBTREE,
};

static struct max8973_regulator_platform_data *max8973_parse_dt(
		struct device *dev)
{
	struct max8973_regulator_platform_data *pdata;
	struct device_node *np = dev->of_node;
	int ret;
	u32 pval;
	bool etr_enable;
	bool etr_sensitivity_high;

	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return NULL;

	pdata->enable_ext_control = of_property_read_bool(np,
						"maxim,externally-enable");
	pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
	pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);

	ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
	if (!ret)
		pdata->dvs_def_state = pval;

	if (of_property_read_bool(np, "maxim,enable-remote-sense"))
		pdata->control_flags  |= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
		pdata->control_flags  |=
				MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-active-discharge"))
		pdata->control_flags  |=
				MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
		pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;

	if (of_property_read_bool(np, "maxim,enable-bias-control"))
		pdata->control_flags  |= MAX8973_CONTROL_BIAS_ENABLE;

	etr_enable = of_property_read_bool(np, "maxim,enable-etr");
	etr_sensitivity_high = of_property_read_bool(np,
				"maxim,enable-high-etr-sensitivity");
	if (etr_sensitivity_high)
		etr_enable = true;

	if (etr_enable) {
		if (etr_sensitivity_high)
			pdata->control_flags |=
				MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US;
		else
			pdata->control_flags |=
				MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US;
	} else {
		pdata->control_flags |= MAX8973_CONTROL_CLKADV_TRIP_DISABLED;
	}

	return pdata;
}

static const struct of_device_id of_max8973_match_tbl[] = {
	{ .compatible = "maxim,max8973", .data = (void *)MAX8973, },
	{ .compatible = "maxim,max77621", .data = (void *)MAX77621, },
	{ },
};
MODULE_DEVICE_TABLE(of, of_max8973_match_tbl);

static int max8973_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct max8973_regulator_platform_data *pdata;
	struct regulator_init_data *ridata;
	struct regulator_config config = { };
	struct regulator_dev *rdev;
	struct max8973_chip *max;
	bool pdata_from_dt = false;
	unsigned int chip_id;
	int ret;

	pdata = dev_get_platdata(&client->dev);

	if (!pdata && client->dev.of_node) {
		pdata = max8973_parse_dt(&client->dev);
		pdata_from_dt = true;
	}

	if (!pdata) {
		dev_err(&client->dev, "No Platform data");
		return -EIO;
	}

	if ((pdata->dvs_gpio == -EPROBE_DEFER) ||
		(pdata->enable_gpio == -EPROBE_DEFER))
		return -EPROBE_DEFER;

	max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
	if (!max)
		return -ENOMEM;

	max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
	if (IS_ERR(max->regmap)) {
		ret = PTR_ERR(max->regmap);
		dev_err(&client->dev, "regmap init failed, err %d\n", ret);
		return ret;
	}

	if (client->dev.of_node) {
		const struct of_device_id *match;

		match = of_match_device(of_match_ptr(of_max8973_match_tbl),
				&client->dev);
		if (!match)
			return -ENODATA;
		max->id = (u32)((uintptr_t)match->data);
	} else {
		max->id = id->driver_data;
	}

	ret = regmap_read(max->regmap, MAX8973_CHIPID1, &chip_id);
	if (ret < 0) {
		dev_err(&client->dev, "register CHIPID1 read failed, %d", ret);
		return ret;
	}

	dev_info(&client->dev, "CHIP-ID OTP: 0x%02x ID_M: 0x%02x\n",
			(chip_id >> 4) & 0xF, (chip_id >> 1) & 0x7);

	i2c_set_clientdata(client, max);
	max->ops = max8973_dcdc_ops;
	max->dev = &client->dev;
	max->desc.name = id->name;
	max->desc.id = 0;
	max->desc.ops = &max->ops;
	max->desc.type = REGULATOR_VOLTAGE;
	max->desc.owner = THIS_MODULE;
	max->desc.min_uV = MAX8973_MIN_VOLATGE;
	max->desc.uV_step = MAX8973_VOLATGE_STEP;
	max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;

	max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
	max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
	max->enable_external_control = pdata->enable_ext_control;
	max->curr_gpio_val = pdata->dvs_def_state;
	max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;

	if (gpio_is_valid(max->enable_gpio))
		max->enable_external_control = true;

	max->lru_index[0] = max->curr_vout_reg;

	if (gpio_is_valid(max->dvs_gpio)) {
		int gpio_flags;
		int i;

		gpio_flags = (pdata->dvs_def_state) ?
				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
		ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
				gpio_flags, "max8973-dvs");
		if (ret) {
			dev_err(&client->dev,
				"gpio_request for gpio %d failed, err = %d\n",
				max->dvs_gpio, ret);
			return ret;
		}

		/*
		 * Initialize the lru index with vout_reg id
		 * The index 0 will be most recently used and
		 * set with the max->curr_vout_reg */
		for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
			max->lru_index[i] = i;
		max->lru_index[0] = max->curr_vout_reg;
		max->lru_index[max->curr_vout_reg] = 0;
	} else {
		/*
		 * If there is no DVS GPIO, the VOUT register
		 * address is fixed.
		 */
		max->ops.set_voltage_sel = regulator_set_voltage_sel_regmap;
		max->ops.get_voltage_sel = regulator_get_voltage_sel_regmap;
		max->desc.vsel_reg = max->curr_vout_reg;
		max->desc.vsel_mask = MAX8973_VOUT_MASK;
	}

	if (pdata_from_dt)
		pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
					client->dev.of_node, &max->desc);

	ridata = pdata->reg_init_data;
	switch (max->id) {
	case MAX8973:
		if (!pdata->enable_ext_control) {
			max->desc.enable_reg = MAX8973_VOUT;
			max->desc.enable_mask = MAX8973_VOUT_ENABLE;
			max->ops.enable = regulator_enable_regmap;
			max->ops.disable = regulator_disable_regmap;
			max->ops.is_enabled = regulator_is_enabled_regmap;
			break;
		}

		if (gpio_is_valid(max->enable_gpio)) {
			config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
			if (ridata && (ridata->constraints.always_on ||
					ridata->constraints.boot_on))
				config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
			config.ena_gpio = max->enable_gpio;
		}
		break;

	case MAX77621:
		if (gpio_is_valid(max->enable_gpio)) {
			ret = devm_gpio_request_one(&client->dev,
					max->enable_gpio, GPIOF_OUT_INIT_HIGH,
					"max8973-en-gpio");
			if (ret) {
				dev_err(&client->dev,
					"gpio_request for gpio %d failed: %d\n",
					max->enable_gpio, ret);
				return ret;
			}
		}

		max->desc.enable_reg = MAX8973_VOUT;
		max->desc.enable_mask = MAX8973_VOUT_ENABLE;
		max->ops.enable = regulator_enable_regmap;
		max->ops.disable = regulator_disable_regmap;
		max->ops.is_enabled = regulator_is_enabled_regmap;
		max->ops.set_current_limit = max8973_set_current_limit;
		max->ops.get_current_limit = max8973_get_current_limit;
		break;
	default:
		break;
	}

	ret = max8973_init_dcdc(max, pdata);
	if (ret < 0) {
		dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
		return ret;
	}

	config.dev = &client->dev;
	config.init_data = pdata->reg_init_data;
	config.driver_data = max;
	config.of_node = client->dev.of_node;
	config.regmap = max->regmap;

	/* Register the regulators */
	rdev = devm_regulator_register(&client->dev, &max->desc, &config);
	if (IS_ERR(rdev)) {
		ret = PTR_ERR(rdev);
		dev_err(max->dev, "regulator register failed, err %d\n", ret);
		return ret;
	}

	return 0;
}

static const struct i2c_device_id max8973_id[] = {
	{.name = "max8973", .driver_data = MAX8973},
	{.name = "max77621", .driver_data = MAX77621},
	{},
};
MODULE_DEVICE_TABLE(i2c, max8973_id);

static struct i2c_driver max8973_i2c_driver = {
	.driver = {
		.name = "max8973",
		.of_match_table = of_max8973_match_tbl,
	},
	.probe = max8973_probe,
	.id_table = max8973_id,
};

static int __init max8973_init(void)
{
	return i2c_add_driver(&max8973_i2c_driver);
}
subsys_initcall(max8973_init);

static void __exit max8973_cleanup(void)
{
	i2c_del_driver(&max8973_i2c_driver);
}
module_exit(max8973_cleanup);

MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
MODULE_LICENSE("GPL v2");