1 /*
2  * max8973-regulator.c -- Maxim max8973
3  *
4  * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator.
5  *
6  * Copyright (c) 2012, NVIDIA Corporation.
7  *
8  * Author: Laxman Dewangan <ldewangan@nvidia.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation version 2.
13  *
14  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
15  * whether express or implied; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
22  * 02111-1307, USA
23  */
24 
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/err.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 #include <linux/platform_device.h>
32 #include <linux/regulator/driver.h>
33 #include <linux/regulator/machine.h>
34 #include <linux/regulator/max8973-regulator.h>
35 #include <linux/regulator/of_regulator.h>
36 #include <linux/gpio.h>
37 #include <linux/of_gpio.h>
38 #include <linux/i2c.h>
39 #include <linux/slab.h>
40 #include <linux/regmap.h>
41 
42 /* Register definitions */
43 #define MAX8973_VOUT					0x0
44 #define MAX8973_VOUT_DVS				0x1
45 #define MAX8973_CONTROL1				0x2
46 #define MAX8973_CONTROL2				0x3
47 #define MAX8973_CHIPID1					0x4
48 #define MAX8973_CHIPID2					0x5
49 
50 #define MAX8973_MAX_VOUT_REG				2
51 
52 /* MAX8973_VOUT */
53 #define MAX8973_VOUT_ENABLE				BIT(7)
54 #define MAX8973_VOUT_MASK				0x7F
55 
56 /* MAX8973_VOUT_DVS */
57 #define MAX8973_DVS_VOUT_MASK				0x7F
58 
59 /* MAX8973_CONTROL1 */
60 #define MAX8973_SNS_ENABLE				BIT(7)
61 #define MAX8973_FPWM_EN_M				BIT(6)
62 #define MAX8973_NFSR_ENABLE				BIT(5)
63 #define MAX8973_AD_ENABLE				BIT(4)
64 #define MAX8973_BIAS_ENABLE				BIT(3)
65 #define MAX8973_FREQSHIFT_9PER				BIT(2)
66 
67 #define MAX8973_RAMP_12mV_PER_US			0x0
68 #define MAX8973_RAMP_25mV_PER_US			0x1
69 #define MAX8973_RAMP_50mV_PER_US			0x2
70 #define MAX8973_RAMP_200mV_PER_US			0x3
71 #define MAX8973_RAMP_MASK				0x3
72 
73 /* MAX8973_CONTROL2 */
74 #define MAX8973_WDTMR_ENABLE				BIT(6)
75 #define MAX8973_DISCH_ENBABLE				BIT(5)
76 #define MAX8973_FT_ENABLE				BIT(4)
77 
78 #define MAX8973_CKKADV_TRIP_DISABLE			0xC
79 #define MAX8973_CKKADV_TRIP_75mV_PER_US			0x0
80 #define MAX8973_CKKADV_TRIP_150mV_PER_US		0x4
81 #define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS	0x8
82 #define MAX8973_CONTROL_CLKADV_TRIP_MASK		0x00030000
83 
84 #define MAX8973_INDUCTOR_MIN_30_PER			0x0
85 #define MAX8973_INDUCTOR_NOMINAL			0x1
86 #define MAX8973_INDUCTOR_PLUS_30_PER			0x2
87 #define MAX8973_INDUCTOR_PLUS_60_PER			0x3
88 #define MAX8973_CONTROL_INDUCTOR_VALUE_MASK		0x00300000
89 
90 #define MAX8973_MIN_VOLATGE				606250
91 #define MAX8973_MAX_VOLATGE				1400000
92 #define MAX8973_VOLATGE_STEP				6250
93 #define MAX8973_BUCK_N_VOLTAGE				0x80
94 
95 enum device_id {
96 	MAX8973,
97 	MAX77621
98 };
99 
100 /* Maxim 8973 chip information */
101 struct max8973_chip {
102 	struct device *dev;
103 	struct regulator_desc desc;
104 	struct regmap *regmap;
105 	bool enable_external_control;
106 	int enable_gpio;
107 	int dvs_gpio;
108 	int lru_index[MAX8973_MAX_VOUT_REG];
109 	int curr_vout_val[MAX8973_MAX_VOUT_REG];
110 	int curr_vout_reg;
111 	int curr_gpio_val;
112 	struct regulator_ops ops;
113 	enum device_id id;
114 };
115 
116 /*
117  * find_voltage_set_register: Find new voltage configuration register (VOUT).
118  * The finding of the new VOUT register will be based on the LRU mechanism.
119  * Each VOUT register will have different voltage configured . This
120  * Function will look if any of the VOUT register have requested voltage set
121  * or not.
122  *     - If it is already there then it will make that register as most
123  *       recently used and return as found so that caller need not to set
124  *       the VOUT register but need to set the proper gpios to select this
125  *       VOUT register.
126  *     - If requested voltage is not found then it will use the least
127  *       recently mechanism to get new VOUT register for new configuration
128  *       and will return not_found so that caller need to set new VOUT
129  *       register and then gpios (both).
130  */
131 static bool find_voltage_set_register(struct max8973_chip *tps,
132 		int req_vsel, int *vout_reg, int *gpio_val)
133 {
134 	int i;
135 	bool found = false;
136 	int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
137 	int found_index = MAX8973_MAX_VOUT_REG - 1;
138 
139 	for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
140 		if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
141 			new_vout_reg = tps->lru_index[i];
142 			found_index = i;
143 			found = true;
144 			goto update_lru_index;
145 		}
146 	}
147 
148 update_lru_index:
149 	for (i = found_index; i > 0; i--)
150 		tps->lru_index[i] = tps->lru_index[i - 1];
151 
152 	tps->lru_index[0] = new_vout_reg;
153 	*gpio_val = new_vout_reg;
154 	*vout_reg = MAX8973_VOUT + new_vout_reg;
155 	return found;
156 }
157 
158 static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
159 {
160 	struct max8973_chip *max = rdev_get_drvdata(rdev);
161 	unsigned int data;
162 	int ret;
163 
164 	ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
165 	if (ret < 0) {
166 		dev_err(max->dev, "register %d read failed, err = %d\n",
167 			max->curr_vout_reg, ret);
168 		return ret;
169 	}
170 	return data & MAX8973_VOUT_MASK;
171 }
172 
173 static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
174 	     unsigned vsel)
175 {
176 	struct max8973_chip *max = rdev_get_drvdata(rdev);
177 	int ret;
178 	bool found = false;
179 	int vout_reg = max->curr_vout_reg;
180 	int gpio_val = max->curr_gpio_val;
181 
182 	/*
183 	 * If gpios are available to select the VOUT register then least
184 	 * recently used register for new configuration.
185 	 */
186 	if (gpio_is_valid(max->dvs_gpio))
187 		found = find_voltage_set_register(max, vsel,
188 					&vout_reg, &gpio_val);
189 
190 	if (!found) {
191 		ret = regmap_update_bits(max->regmap, vout_reg,
192 					MAX8973_VOUT_MASK, vsel);
193 		if (ret < 0) {
194 			dev_err(max->dev, "register %d update failed, err %d\n",
195 				 vout_reg, ret);
196 			return ret;
197 		}
198 		max->curr_vout_reg = vout_reg;
199 		max->curr_vout_val[gpio_val] = vsel;
200 	}
201 
202 	/* Select proper VOUT register vio gpios */
203 	if (gpio_is_valid(max->dvs_gpio)) {
204 		gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1);
205 		max->curr_gpio_val = gpio_val;
206 	}
207 	return 0;
208 }
209 
210 static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
211 {
212 	struct max8973_chip *max = rdev_get_drvdata(rdev);
213 	int ret;
214 	int pwm;
215 
216 	/* Enable force PWM mode in FAST mode only. */
217 	switch (mode) {
218 	case REGULATOR_MODE_FAST:
219 		pwm = MAX8973_FPWM_EN_M;
220 		break;
221 
222 	case REGULATOR_MODE_NORMAL:
223 		pwm = 0;
224 		break;
225 
226 	default:
227 		return -EINVAL;
228 	}
229 
230 	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
231 				MAX8973_FPWM_EN_M, pwm);
232 	if (ret < 0)
233 		dev_err(max->dev, "register %d update failed, err %d\n",
234 				MAX8973_CONTROL1, ret);
235 	return ret;
236 }
237 
238 static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
239 {
240 	struct max8973_chip *max = rdev_get_drvdata(rdev);
241 	unsigned int data;
242 	int ret;
243 
244 	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
245 	if (ret < 0) {
246 		dev_err(max->dev, "register %d read failed, err %d\n",
247 				MAX8973_CONTROL1, ret);
248 		return ret;
249 	}
250 	return (data & MAX8973_FPWM_EN_M) ?
251 		REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
252 }
253 
254 static int max8973_set_ramp_delay(struct regulator_dev *rdev,
255 		int ramp_delay)
256 {
257 	struct max8973_chip *max = rdev_get_drvdata(rdev);
258 	unsigned int control;
259 	int ret;
260 	int ret_val;
261 
262 	/* Set ramp delay */
263 	if (ramp_delay < 25000) {
264 		control = MAX8973_RAMP_12mV_PER_US;
265 		ret_val = 12000;
266 	} else if (ramp_delay < 50000) {
267 		control = MAX8973_RAMP_25mV_PER_US;
268 		ret_val = 25000;
269 	} else if (ramp_delay < 200000) {
270 		control = MAX8973_RAMP_50mV_PER_US;
271 		ret_val = 50000;
272 	} else {
273 		control = MAX8973_RAMP_200mV_PER_US;
274 		ret_val = 200000;
275 	}
276 
277 	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
278 			MAX8973_RAMP_MASK, control);
279 	if (ret < 0)
280 		dev_err(max->dev, "register %d update failed, %d",
281 				MAX8973_CONTROL1, ret);
282 	return ret;
283 }
284 
285 static const struct regulator_ops max8973_dcdc_ops = {
286 	.get_voltage_sel	= max8973_dcdc_get_voltage_sel,
287 	.set_voltage_sel	= max8973_dcdc_set_voltage_sel,
288 	.list_voltage		= regulator_list_voltage_linear,
289 	.set_mode		= max8973_dcdc_set_mode,
290 	.get_mode		= max8973_dcdc_get_mode,
291 	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
292 	.set_ramp_delay		= max8973_set_ramp_delay,
293 };
294 
295 static int max8973_init_dcdc(struct max8973_chip *max,
296 			     struct max8973_regulator_platform_data *pdata)
297 {
298 	int ret;
299 	uint8_t	control1 = 0;
300 	uint8_t control2 = 0;
301 	unsigned int data;
302 
303 	ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
304 	if (ret < 0) {
305 		dev_err(max->dev, "register %d read failed, err = %d",
306 				MAX8973_CONTROL1, ret);
307 		return ret;
308 	}
309 	control1 = data & MAX8973_RAMP_MASK;
310 	switch (control1) {
311 	case MAX8973_RAMP_12mV_PER_US:
312 		max->desc.ramp_delay = 12000;
313 		break;
314 	case MAX8973_RAMP_25mV_PER_US:
315 		max->desc.ramp_delay = 25000;
316 		break;
317 	case MAX8973_RAMP_50mV_PER_US:
318 		max->desc.ramp_delay = 50000;
319 		break;
320 	case MAX8973_RAMP_200mV_PER_US:
321 		max->desc.ramp_delay = 200000;
322 		break;
323 	}
324 
325 	if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
326 		control1 |= MAX8973_SNS_ENABLE;
327 
328 	if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
329 		control1 |= MAX8973_NFSR_ENABLE;
330 
331 	if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
332 		control1 |= MAX8973_AD_ENABLE;
333 
334 	if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
335 		control1 |= MAX8973_BIAS_ENABLE;
336 		max->desc.enable_time = 20;
337 	} else {
338 		max->desc.enable_time = 240;
339 	}
340 
341 	if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
342 		control1 |= MAX8973_FREQSHIFT_9PER;
343 
344 	if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
345 		control2 |= MAX8973_DISCH_ENBABLE;
346 
347 	/*  Clock advance trip configuration */
348 	switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
349 	case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
350 		control2 |= MAX8973_CKKADV_TRIP_DISABLE;
351 		break;
352 
353 	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
354 		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
355 		break;
356 
357 	case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
358 		control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
359 		break;
360 
361 	case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
362 		control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
363 		break;
364 	}
365 
366 	/* Configure inductor value */
367 	switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
368 	case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
369 		control2 |= MAX8973_INDUCTOR_NOMINAL;
370 		break;
371 
372 	case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
373 		control2 |= MAX8973_INDUCTOR_MIN_30_PER;
374 		break;
375 
376 	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
377 		control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
378 		break;
379 
380 	case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
381 		control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
382 		break;
383 	}
384 
385 	ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
386 	if (ret < 0) {
387 		dev_err(max->dev, "register %d write failed, err = %d",
388 				MAX8973_CONTROL1, ret);
389 		return ret;
390 	}
391 
392 	ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
393 	if (ret < 0) {
394 		dev_err(max->dev, "register %d write failed, err = %d",
395 				MAX8973_CONTROL2, ret);
396 		return ret;
397 	}
398 
399 	/* If external control is enabled then disable EN bit */
400 	if (max->enable_external_control && (max->id == MAX8973)) {
401 		ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
402 						MAX8973_VOUT_ENABLE, 0);
403 		if (ret < 0)
404 			dev_err(max->dev, "register %d update failed, err = %d",
405 				MAX8973_VOUT, ret);
406 	}
407 	return ret;
408 }
409 
410 static const struct regmap_config max8973_regmap_config = {
411 	.reg_bits		= 8,
412 	.val_bits		= 8,
413 	.max_register		= MAX8973_CHIPID2,
414 	.cache_type		= REGCACHE_RBTREE,
415 };
416 
417 static struct max8973_regulator_platform_data *max8973_parse_dt(
418 		struct device *dev)
419 {
420 	struct max8973_regulator_platform_data *pdata;
421 	struct device_node *np = dev->of_node;
422 	int ret;
423 	u32 pval;
424 
425 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
426 	if (!pdata)
427 		return NULL;
428 
429 	pdata->enable_ext_control = of_property_read_bool(np,
430 						"maxim,externally-enable");
431 	pdata->enable_gpio = of_get_named_gpio(np, "maxim,enable-gpio", 0);
432 	pdata->dvs_gpio = of_get_named_gpio(np, "maxim,dvs-gpio", 0);
433 
434 	ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
435 	if (!ret)
436 		pdata->dvs_def_state = pval;
437 
438 	if (of_property_read_bool(np, "maxim,enable-remote-sense"))
439 		pdata->control_flags  |= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;
440 
441 	if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
442 		pdata->control_flags  |=
443 				MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;
444 
445 	if (of_property_read_bool(np, "maxim,enable-active-discharge"))
446 		pdata->control_flags  |=
447 				MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;
448 
449 	if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
450 		pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;
451 
452 	if (of_property_read_bool(np, "maxim,enable-bias-control"))
453 		pdata->control_flags  |= MAX8973_CONTROL_BIAS_ENABLE;
454 
455 	return pdata;
456 }
457 
458 static const struct of_device_id of_max8973_match_tbl[] = {
459 	{ .compatible = "maxim,max8973", .data = (void *)MAX8973, },
460 	{ .compatible = "maxim,max77621", .data = (void *)MAX77621, },
461 	{ },
462 };
463 MODULE_DEVICE_TABLE(of, of_max8973_match_tbl);
464 
465 static int max8973_probe(struct i2c_client *client,
466 			 const struct i2c_device_id *id)
467 {
468 	struct max8973_regulator_platform_data *pdata;
469 	struct regulator_init_data *ridata;
470 	struct regulator_config config = { };
471 	struct regulator_dev *rdev;
472 	struct max8973_chip *max;
473 	bool pdata_from_dt = false;
474 	unsigned int chip_id;
475 	int ret;
476 
477 	pdata = dev_get_platdata(&client->dev);
478 
479 	if (!pdata && client->dev.of_node) {
480 		pdata = max8973_parse_dt(&client->dev);
481 		pdata_from_dt = true;
482 	}
483 
484 	if (!pdata) {
485 		dev_err(&client->dev, "No Platform data");
486 		return -EIO;
487 	}
488 
489 	if ((pdata->dvs_gpio == -EPROBE_DEFER) ||
490 		(pdata->enable_gpio == -EPROBE_DEFER))
491 		return -EPROBE_DEFER;
492 
493 	max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
494 	if (!max)
495 		return -ENOMEM;
496 
497 	max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
498 	if (IS_ERR(max->regmap)) {
499 		ret = PTR_ERR(max->regmap);
500 		dev_err(&client->dev, "regmap init failed, err %d\n", ret);
501 		return ret;
502 	}
503 
504 	if (client->dev.of_node) {
505 		const struct of_device_id *match;
506 
507 		match = of_match_device(of_match_ptr(of_max8973_match_tbl),
508 				&client->dev);
509 		if (!match)
510 			return -ENODATA;
511 		max->id = (u32)((uintptr_t)match->data);
512 	} else {
513 		max->id = id->driver_data;
514 	}
515 
516 	ret = regmap_read(max->regmap, MAX8973_CHIPID1, &chip_id);
517 	if (ret < 0) {
518 		dev_err(&client->dev, "register CHIPID1 read failed, %d", ret);
519 		return ret;
520 	}
521 
522 	dev_info(&client->dev, "CHIP-ID OTP: 0x%02x ID_M: 0x%02x\n",
523 			(chip_id >> 4) & 0xF, (chip_id >> 1) & 0x7);
524 
525 	i2c_set_clientdata(client, max);
526 	max->ops = max8973_dcdc_ops;
527 	max->dev = &client->dev;
528 	max->desc.name = id->name;
529 	max->desc.id = 0;
530 	max->desc.ops = &max->ops;
531 	max->desc.type = REGULATOR_VOLTAGE;
532 	max->desc.owner = THIS_MODULE;
533 	max->desc.min_uV = MAX8973_MIN_VOLATGE;
534 	max->desc.uV_step = MAX8973_VOLATGE_STEP;
535 	max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
536 
537 	max->dvs_gpio = (pdata->dvs_gpio) ? pdata->dvs_gpio : -EINVAL;
538 	max->enable_gpio = (pdata->enable_gpio) ? pdata->enable_gpio : -EINVAL;
539 	max->enable_external_control = pdata->enable_ext_control;
540 	max->curr_gpio_val = pdata->dvs_def_state;
541 	max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
542 
543 	if (gpio_is_valid(max->enable_gpio))
544 		max->enable_external_control = true;
545 
546 	max->lru_index[0] = max->curr_vout_reg;
547 
548 	if (gpio_is_valid(max->dvs_gpio)) {
549 		int gpio_flags;
550 		int i;
551 
552 		gpio_flags = (pdata->dvs_def_state) ?
553 				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
554 		ret = devm_gpio_request_one(&client->dev, max->dvs_gpio,
555 				gpio_flags, "max8973-dvs");
556 		if (ret) {
557 			dev_err(&client->dev,
558 				"gpio_request for gpio %d failed, err = %d\n",
559 				max->dvs_gpio, ret);
560 			return ret;
561 		}
562 
563 		/*
564 		 * Initialize the lru index with vout_reg id
565 		 * The index 0 will be most recently used and
566 		 * set with the max->curr_vout_reg */
567 		for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
568 			max->lru_index[i] = i;
569 		max->lru_index[0] = max->curr_vout_reg;
570 		max->lru_index[max->curr_vout_reg] = 0;
571 	}
572 
573 	if (pdata_from_dt)
574 		pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
575 					client->dev.of_node, &max->desc);
576 
577 	ridata = pdata->reg_init_data;
578 	switch (max->id) {
579 	case MAX8973:
580 		if (!pdata->enable_ext_control) {
581 			max->desc.enable_reg = MAX8973_VOUT;
582 			max->desc.enable_mask = MAX8973_VOUT_ENABLE;
583 			max->ops.enable = regulator_enable_regmap;
584 			max->ops.disable = regulator_disable_regmap;
585 			max->ops.is_enabled = regulator_is_enabled_regmap;
586 			break;
587 		}
588 
589 		if (gpio_is_valid(max->enable_gpio)) {
590 			config.ena_gpio_flags = GPIOF_OUT_INIT_LOW;
591 			if (ridata && (ridata->constraints.always_on ||
592 					ridata->constraints.boot_on))
593 				config.ena_gpio_flags = GPIOF_OUT_INIT_HIGH;
594 			config.ena_gpio = max->enable_gpio;
595 		}
596 		break;
597 
598 	case MAX77621:
599 		if (gpio_is_valid(max->enable_gpio)) {
600 			ret = devm_gpio_request_one(&client->dev,
601 					max->enable_gpio, GPIOF_OUT_INIT_HIGH,
602 					"max8973-en-gpio");
603 			if (ret) {
604 				dev_err(&client->dev,
605 					"gpio_request for gpio %d failed: %d\n",
606 					max->enable_gpio, ret);
607 				return ret;
608 			}
609 		}
610 
611 		max->desc.enable_reg = MAX8973_VOUT;
612 		max->desc.enable_mask = MAX8973_VOUT_ENABLE;
613 		max->ops.enable = regulator_enable_regmap;
614 		max->ops.disable = regulator_disable_regmap;
615 		max->ops.is_enabled = regulator_is_enabled_regmap;
616 		break;
617 	default:
618 		break;
619 	}
620 
621 	ret = max8973_init_dcdc(max, pdata);
622 	if (ret < 0) {
623 		dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
624 		return ret;
625 	}
626 
627 	config.dev = &client->dev;
628 	config.init_data = pdata->reg_init_data;
629 	config.driver_data = max;
630 	config.of_node = client->dev.of_node;
631 	config.regmap = max->regmap;
632 
633 	/* Register the regulators */
634 	rdev = devm_regulator_register(&client->dev, &max->desc, &config);
635 	if (IS_ERR(rdev)) {
636 		ret = PTR_ERR(rdev);
637 		dev_err(max->dev, "regulator register failed, err %d\n", ret);
638 		return ret;
639 	}
640 
641 	return 0;
642 }
643 
644 static const struct i2c_device_id max8973_id[] = {
645 	{.name = "max8973", .driver_data = MAX8973},
646 	{.name = "max77621", .driver_data = MAX77621},
647 	{},
648 };
649 MODULE_DEVICE_TABLE(i2c, max8973_id);
650 
651 static struct i2c_driver max8973_i2c_driver = {
652 	.driver = {
653 		.name = "max8973",
654 		.of_match_table = of_max8973_match_tbl,
655 		.owner = THIS_MODULE,
656 	},
657 	.probe = max8973_probe,
658 	.id_table = max8973_id,
659 };
660 
661 static int __init max8973_init(void)
662 {
663 	return i2c_add_driver(&max8973_i2c_driver);
664 }
665 subsys_initcall(max8973_init);
666 
667 static void __exit max8973_cleanup(void)
668 {
669 	i2c_del_driver(&max8973_i2c_driver);
670 }
671 module_exit(max8973_cleanup);
672 
673 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
674 MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
675 MODULE_LICENSE("GPL v2");
676