Contributors: 3
Author Tokens Token Proportion Commits Commit Proportion
Guodong Xu 2314 99.23% 2 33.33%
Axel Lin 17 0.73% 3 50.00%
Baoyou Xie 1 0.04% 1 16.67%
Total 2332 6 


/*
 * Device driver for regulators in Hi6421 IC
 *
 * Copyright (c) <2011-2014> HiSilicon Technologies Co., Ltd.
 *              http://www.hisilicon.com
 * Copyright (c) <2013-2014> Linaro Ltd.
 *              http://www.linaro.org
 *
 * Author: Guodong Xu <guodong.xu@linaro.org>
 *
 * 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.
 */

#include <linux/slab.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/mfd/hi6421-pmic.h>

/*
 * struct hi6421_regulator_pdata - Hi6421 regulator data of platform device
 * @lock: mutex to serialize regulator enable
 */
struct hi6421_regulator_pdata {
	struct mutex lock;
};

/*
 * struct hi6421_regulator_info - hi6421 regulator information
 * @desc: regulator description
 * @mode_mask: ECO mode bitmask of LDOs; for BUCKs, this masks sleep
 * @eco_microamp: eco mode load upper limit (in uA), valid for LDOs only
 */
struct hi6421_regulator_info {
	struct regulator_desc	desc;
	u8		mode_mask;
	u32		eco_microamp;
};

/* HI6421 regulators */
enum hi6421_regulator_id {
	HI6421_LDO0,
	HI6421_LDO1,
	HI6421_LDO2,
	HI6421_LDO3,
	HI6421_LDO4,
	HI6421_LDO5,
	HI6421_LDO6,
	HI6421_LDO7,
	HI6421_LDO8,
	HI6421_LDO9,
	HI6421_LDO10,
	HI6421_LDO11,
	HI6421_LDO12,
	HI6421_LDO13,
	HI6421_LDO14,
	HI6421_LDO15,
	HI6421_LDO16,
	HI6421_LDO17,
	HI6421_LDO18,
	HI6421_LDO19,
	HI6421_LDO20,
	HI6421_LDOAUDIO,
	HI6421_BUCK0,
	HI6421_BUCK1,
	HI6421_BUCK2,
	HI6421_BUCK3,
	HI6421_BUCK4,
	HI6421_BUCK5,
	HI6421_NUM_REGULATORS,
};

#define HI6421_REGULATOR_OF_MATCH(_name, id)				\
{									\
	.name = #_name,							\
	.driver_data = (void *) HI6421_##id,				\
}

static struct of_regulator_match hi6421_regulator_match[] = {
	HI6421_REGULATOR_OF_MATCH(hi6421_vout0, LDO0),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout1, LDO1),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout2, LDO2),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout3, LDO3),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout4, LDO4),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout5, LDO5),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout6, LDO6),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout7, LDO7),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout8, LDO8),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout9, LDO9),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout10, LDO10),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout11, LDO11),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout12, LDO12),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout13, LDO13),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout14, LDO14),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout15, LDO15),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout16, LDO16),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout17, LDO17),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout18, LDO18),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout19, LDO19),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout20, LDO20),
	HI6421_REGULATOR_OF_MATCH(hi6421_vout_audio, LDOAUDIO),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck0, BUCK0),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck1, BUCK1),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck2, BUCK2),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck3, BUCK3),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck4, BUCK4),
	HI6421_REGULATOR_OF_MATCH(hi6421_buck5, BUCK5),
};

/* LDO 0, 4~7, 9~14, 16~20 have same voltage table. */
static const unsigned int ldo_0_voltages[] = {
	1500000, 1800000, 2400000, 2500000,
	2600000, 2700000, 2850000, 3000000,
};

/* LDO 8, 15 have same voltage table. */
static const unsigned int ldo_8_voltages[] = {
	1500000, 1800000, 2400000, 2600000,
	2700000, 2850000, 3000000, 3300000,
};

/* Ranges are sorted in ascending order. */
static const struct regulator_linear_range ldo_audio_volt_range[] = {
	REGULATOR_LINEAR_RANGE(2800000, 0, 3, 50000),
	REGULATOR_LINEAR_RANGE(3000000, 4, 7, 100000),
};

static const unsigned int buck_3_voltages[] = {
	 950000, 1050000, 1100000, 1117000,
	1134000, 1150000, 1167000, 1200000,
};

static const unsigned int buck_4_voltages[] = {
	1150000, 1200000, 1250000, 1350000,
	1700000, 1800000, 1900000, 2000000,
};

static const unsigned int buck_5_voltages[] = {
	1150000, 1200000, 1250000, 1350000,
	1600000, 1700000, 1800000, 1900000,
};

static const struct regulator_ops hi6421_ldo_ops;
static const struct regulator_ops hi6421_ldo_linear_ops;
static const struct regulator_ops hi6421_ldo_linear_range_ops;
static const struct regulator_ops hi6421_buck012_ops;
static const struct regulator_ops hi6421_buck345_ops;

#define HI6421_LDO_ENABLE_TIME (350)
/*
 * _id - LDO id name string
 * v_table - voltage table
 * vreg - voltage select register
 * vmask - voltage select mask
 * ereg - enable register
 * emask - enable mask
 * odelay - off/on delay time in uS
 * ecomask - eco mode mask
 * ecoamp - eco mode load uppler limit in uA
 */
#define HI6421_LDO(_id, v_table, vreg, vmask, ereg, emask,		\
		   odelay, ecomask, ecoamp)				\
	[HI6421_##_id] = {						\
		.desc = {						\
			.name		= #_id,				\
			.ops		= &hi6421_ldo_ops,		\
			.type		= REGULATOR_VOLTAGE,		\
			.id		= HI6421_##_id,			\
			.owner		= THIS_MODULE,			\
			.n_voltages	= ARRAY_SIZE(v_table),		\
			.volt_table	= v_table,			\
			.vsel_reg	= HI6421_REG_TO_BUS_ADDR(vreg),	\
			.vsel_mask	= vmask,			\
			.enable_reg	= HI6421_REG_TO_BUS_ADDR(ereg),	\
			.enable_mask	= emask,			\
			.enable_time	= HI6421_LDO_ENABLE_TIME,	\
			.off_on_delay	= odelay,			\
		},							\
		.mode_mask		= ecomask,			\
		.eco_microamp		= ecoamp,			\
	}

/* HI6421 LDO1~3 are linear voltage regulators at fixed uV_step
 *
 * _id - LDO id name string
 * _min_uV - minimum voltage supported in uV
 * n_volt - number of votages available
 * vstep - voltage increase in each linear step in uV
 * vreg - voltage select register
 * vmask - voltage select mask
 * ereg - enable register
 * emask - enable mask
 * odelay - off/on delay time in uS
 * ecomask - eco mode mask
 * ecoamp - eco mode load uppler limit in uA
 */
#define HI6421_LDO_LINEAR(_id, _min_uV, n_volt, vstep, vreg, vmask,	\
			  ereg, emask, odelay, ecomask, ecoamp)		\
	[HI6421_##_id] = {						\
		.desc = {						\
			.name		= #_id,				\
			.ops		= &hi6421_ldo_linear_ops,	\
			.type		= REGULATOR_VOLTAGE,		\
			.id		= HI6421_##_id,			\
			.owner		= THIS_MODULE,			\
			.min_uV		= _min_uV,			\
			.n_voltages	= n_volt,			\
			.uV_step	= vstep,			\
			.vsel_reg	= HI6421_REG_TO_BUS_ADDR(vreg),	\
			.vsel_mask	= vmask,			\
			.enable_reg	= HI6421_REG_TO_BUS_ADDR(ereg),	\
			.enable_mask	= emask,			\
			.enable_time	= HI6421_LDO_ENABLE_TIME,	\
			.off_on_delay	= odelay,			\
		},							\
		.mode_mask		= ecomask,			\
		.eco_microamp		= ecoamp,			\
	}

/* HI6421 LDOAUDIO is a linear voltage regulator with two 4-step ranges
 *
 * _id - LDO id name string
 * n_volt - number of votages available
 * volt_ranges - array of regulator_linear_range
 * vstep - voltage increase in each linear step in uV
 * vreg - voltage select register
 * vmask - voltage select mask
 * ereg - enable register
 * emask - enable mask
 * odelay - off/on delay time in uS
 * ecomask - eco mode mask
 * ecoamp - eco mode load uppler limit in uA
 */
#define HI6421_LDO_LINEAR_RANGE(_id, n_volt, volt_ranges, vreg, vmask,	\
				ereg, emask, odelay, ecomask, ecoamp)	\
	[HI6421_##_id] = {						\
		.desc = {						\
			.name		= #_id,				\
			.ops		= &hi6421_ldo_linear_range_ops,	\
			.type		= REGULATOR_VOLTAGE,		\
			.id		= HI6421_##_id,			\
			.owner		= THIS_MODULE,			\
			.n_voltages	= n_volt,			\
			.linear_ranges	= volt_ranges,			\
			.n_linear_ranges = ARRAY_SIZE(volt_ranges),	\
			.vsel_reg	= HI6421_REG_TO_BUS_ADDR(vreg),	\
			.vsel_mask	= vmask,			\
			.enable_reg	= HI6421_REG_TO_BUS_ADDR(ereg),	\
			.enable_mask	= emask,			\
			.enable_time	= HI6421_LDO_ENABLE_TIME,	\
			.off_on_delay	= odelay,			\
		},							\
		.mode_mask		= ecomask,			\
		.eco_microamp		= ecoamp,			\
	}

/* HI6421 BUCK0/1/2 are linear voltage regulators at fixed uV_step
 *
 * _id - BUCK0/1/2 id name string
 * vreg - voltage select register
 * vmask - voltage select mask
 * ereg - enable register
 * emask - enable mask
 * sleepmask - mask of sleep mode
 * etime - enable time
 * odelay - off/on delay time in uS
 */
#define HI6421_BUCK012(_id, vreg, vmask, ereg, emask, sleepmask,	\
			etime, odelay)					\
	[HI6421_##_id] = {						\
		.desc = {						\
			.name		= #_id,				\
			.ops		= &hi6421_buck012_ops,		\
			.type		= REGULATOR_VOLTAGE,		\
			.id		= HI6421_##_id,			\
			.owner		= THIS_MODULE,			\
			.min_uV		= 700000,			\
			.n_voltages	= 128,				\
			.uV_step	= 7086,				\
			.vsel_reg	= HI6421_REG_TO_BUS_ADDR(vreg),	\
			.vsel_mask	= vmask,			\
			.enable_reg	= HI6421_REG_TO_BUS_ADDR(ereg),	\
			.enable_mask	= emask,			\
			.enable_time	= etime,			\
			.off_on_delay	= odelay,			\
		},							\
		.mode_mask		= sleepmask,			\
	}

/* HI6421 BUCK3/4/5 share similar configurations as LDOs, with exception
 *  that it supports SLEEP mode, so has different .ops.
 *
 * _id - LDO id name string
 * v_table - voltage table
 * vreg - voltage select register
 * vmask - voltage select mask
 * ereg - enable register
 * emask - enable mask
 * odelay - off/on delay time in uS
 * sleepmask - mask of sleep mode
 */
#define HI6421_BUCK345(_id, v_table, vreg, vmask, ereg, emask,		\
			odelay, sleepmask)				\
	[HI6421_##_id] = {						\
		.desc = {						\
			.name		= #_id,				\
			.ops		= &hi6421_buck345_ops,		\
			.type		= REGULATOR_VOLTAGE,		\
			.id		= HI6421_##_id,			\
			.owner		= THIS_MODULE,			\
			.n_voltages	= ARRAY_SIZE(v_table),		\
			.volt_table	= v_table,			\
			.vsel_reg	= HI6421_REG_TO_BUS_ADDR(vreg),	\
			.vsel_mask	= vmask,			\
			.enable_reg	= HI6421_REG_TO_BUS_ADDR(ereg),	\
			.enable_mask	= emask,			\
			.enable_time	= HI6421_LDO_ENABLE_TIME,	\
			.off_on_delay	= odelay,			\
		},							\
		.mode_mask		= sleepmask,			\
	}

/* HI6421 regulator information */
static struct hi6421_regulator_info
		hi6421_regulator_info[HI6421_NUM_REGULATORS] = {
	HI6421_LDO(LDO0, ldo_0_voltages, 0x20, 0x07, 0x20, 0x10,
		   10000, 0x20, 8000),
	HI6421_LDO_LINEAR(LDO1, 1700000, 4, 100000, 0x21, 0x03, 0x21, 0x10,
			  10000, 0x20, 5000),
	HI6421_LDO_LINEAR(LDO2, 1050000, 8, 50000, 0x22, 0x07, 0x22, 0x10,
			  20000, 0x20, 8000),
	HI6421_LDO_LINEAR(LDO3, 1050000, 8, 50000, 0x23, 0x07, 0x23, 0x10,
			  20000, 0x20, 8000),
	HI6421_LDO(LDO4, ldo_0_voltages, 0x24, 0x07, 0x24, 0x10,
		   20000, 0x20, 8000),
	HI6421_LDO(LDO5, ldo_0_voltages, 0x25, 0x07, 0x25, 0x10,
		   20000, 0x20, 8000),
	HI6421_LDO(LDO6, ldo_0_voltages, 0x26, 0x07, 0x26, 0x10,
		   20000, 0x20, 8000),
	HI6421_LDO(LDO7, ldo_0_voltages, 0x27, 0x07, 0x27, 0x10,
		   20000, 0x20, 5000),
	HI6421_LDO(LDO8, ldo_8_voltages, 0x28, 0x07, 0x28, 0x10,
		   20000, 0x20, 8000),
	HI6421_LDO(LDO9, ldo_0_voltages, 0x29, 0x07, 0x29, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO10, ldo_0_voltages, 0x2a, 0x07, 0x2a, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO11, ldo_0_voltages, 0x2b, 0x07, 0x2b, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO12, ldo_0_voltages, 0x2c, 0x07, 0x2c, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO13, ldo_0_voltages, 0x2d, 0x07, 0x2d, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO14, ldo_0_voltages, 0x2e, 0x07, 0x2e, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO15, ldo_8_voltages, 0x2f, 0x07, 0x2f, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO16, ldo_0_voltages, 0x30, 0x07, 0x30, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO17, ldo_0_voltages, 0x31, 0x07, 0x31, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO18, ldo_0_voltages, 0x32, 0x07, 0x32, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO19, ldo_0_voltages, 0x33, 0x07, 0x33, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO(LDO20, ldo_0_voltages, 0x34, 0x07, 0x34, 0x10,
		   40000, 0x20, 8000),
	HI6421_LDO_LINEAR_RANGE(LDOAUDIO, 8, ldo_audio_volt_range, 0x36,
				0x70, 0x36, 0x01, 40000, 0x02, 5000),
	HI6421_BUCK012(BUCK0, 0x0d, 0x7f, 0x0c, 0x01, 0x10, 400, 20000),
	HI6421_BUCK012(BUCK1, 0x0f, 0x7f, 0x0e, 0x01, 0x10, 400, 20000),
	HI6421_BUCK012(BUCK2, 0x11, 0x7f, 0x10, 0x01, 0x10, 350, 100),
	HI6421_BUCK345(BUCK3, buck_3_voltages, 0x13, 0x07, 0x12, 0x01,
		       20000, 0x10),
	HI6421_BUCK345(BUCK4, buck_4_voltages, 0x15, 0x07, 0x14, 0x01,
		       20000, 0x10),
	HI6421_BUCK345(BUCK5, buck_5_voltages, 0x17, 0x07, 0x16, 0x01,
		       20000, 0x10),
};

static int hi6421_regulator_enable(struct regulator_dev *rdev)
{
	struct hi6421_regulator_pdata *pdata;

	pdata = dev_get_drvdata(rdev->dev.parent);
	/* hi6421 spec requires regulator enablement must be serialized:
	 *  - Because when BUCK, LDO switching from off to on, it will have
	 *    a huge instantaneous current; so you can not turn on two or
	 *    more LDO or BUCKs simultaneously, or it may burn the chip.
	 */
	mutex_lock(&pdata->lock);

	/* call regulator regmap helper */
	regulator_enable_regmap(rdev);

	mutex_unlock(&pdata->lock);
	return 0;
}

static unsigned int hi6421_regulator_ldo_get_mode(struct regulator_dev *rdev)
{
	struct hi6421_regulator_info *info = rdev_get_drvdata(rdev);
	u32 reg_val;

	regmap_read(rdev->regmap, rdev->desc->enable_reg, &reg_val);
	if (reg_val & info->mode_mask)
		return REGULATOR_MODE_IDLE;

	return REGULATOR_MODE_NORMAL;
}

static unsigned int hi6421_regulator_buck_get_mode(struct regulator_dev *rdev)
{
	struct hi6421_regulator_info *info = rdev_get_drvdata(rdev);
	u32 reg_val;

	regmap_read(rdev->regmap, rdev->desc->enable_reg, &reg_val);
	if (reg_val & info->mode_mask)
		return REGULATOR_MODE_STANDBY;

	return REGULATOR_MODE_NORMAL;
}

static int hi6421_regulator_ldo_set_mode(struct regulator_dev *rdev,
						unsigned int mode)
{
	struct hi6421_regulator_info *info = rdev_get_drvdata(rdev);
	u32 new_mode;

	switch (mode) {
	case REGULATOR_MODE_NORMAL:
		new_mode = 0;
		break;
	case REGULATOR_MODE_IDLE:
		new_mode = info->mode_mask;
		break;
	default:
		return -EINVAL;
	}

	/* set mode */
	regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
			   info->mode_mask, new_mode);

	return 0;
}

static int hi6421_regulator_buck_set_mode(struct regulator_dev *rdev,
						unsigned int mode)
{
	struct hi6421_regulator_info *info = rdev_get_drvdata(rdev);
	u32 new_mode;

	switch (mode) {
	case REGULATOR_MODE_NORMAL:
		new_mode = 0;
		break;
	case REGULATOR_MODE_STANDBY:
		new_mode = info->mode_mask;
		break;
	default:
		return -EINVAL;
	}

	/* set mode */
	regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
			   info->mode_mask, new_mode);

	return 0;
}

static unsigned int
hi6421_regulator_ldo_get_optimum_mode(struct regulator_dev *rdev,
			int input_uV, int output_uV, int load_uA)
{
	struct hi6421_regulator_info *info = rdev_get_drvdata(rdev);

	if (load_uA > info->eco_microamp)
		return REGULATOR_MODE_NORMAL;

	return REGULATOR_MODE_IDLE;
}

static const struct regulator_ops hi6421_ldo_ops = {
	.is_enabled = regulator_is_enabled_regmap,
	.enable = hi6421_regulator_enable,
	.disable = regulator_disable_regmap,
	.list_voltage = regulator_list_voltage_table,
	.map_voltage = regulator_map_voltage_ascend,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_mode = hi6421_regulator_ldo_get_mode,
	.set_mode = hi6421_regulator_ldo_set_mode,
	.get_optimum_mode = hi6421_regulator_ldo_get_optimum_mode,
};

static const struct regulator_ops hi6421_ldo_linear_ops = {
	.is_enabled = regulator_is_enabled_regmap,
	.enable = hi6421_regulator_enable,
	.disable = regulator_disable_regmap,
	.list_voltage = regulator_list_voltage_linear,
	.map_voltage = regulator_map_voltage_linear,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_mode = hi6421_regulator_ldo_get_mode,
	.set_mode = hi6421_regulator_ldo_set_mode,
	.get_optimum_mode = hi6421_regulator_ldo_get_optimum_mode,
};

static const struct regulator_ops hi6421_ldo_linear_range_ops = {
	.is_enabled = regulator_is_enabled_regmap,
	.enable = hi6421_regulator_enable,
	.disable = regulator_disable_regmap,
	.list_voltage = regulator_list_voltage_linear_range,
	.map_voltage = regulator_map_voltage_linear_range,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_mode = hi6421_regulator_ldo_get_mode,
	.set_mode = hi6421_regulator_ldo_set_mode,
	.get_optimum_mode = hi6421_regulator_ldo_get_optimum_mode,
};

static const struct regulator_ops hi6421_buck012_ops = {
	.is_enabled = regulator_is_enabled_regmap,
	.enable = hi6421_regulator_enable,
	.disable = regulator_disable_regmap,
	.list_voltage = regulator_list_voltage_linear,
	.map_voltage = regulator_map_voltage_linear,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_mode = hi6421_regulator_buck_get_mode,
	.set_mode = hi6421_regulator_buck_set_mode,
};

static const struct regulator_ops hi6421_buck345_ops = {
	.is_enabled = regulator_is_enabled_regmap,
	.enable = hi6421_regulator_enable,
	.disable = regulator_disable_regmap,
	.list_voltage = regulator_list_voltage_table,
	.map_voltage = regulator_map_voltage_ascend,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_mode = hi6421_regulator_buck_get_mode,
	.set_mode = hi6421_regulator_buck_set_mode,
};

static int hi6421_regulator_register(struct platform_device *pdev,
				     struct regmap *rmap,
				     struct regulator_init_data *init_data,
				     int id, struct device_node *np)
{
	struct hi6421_regulator_info *info = NULL;
	struct regulator_config config = { };
	struct regulator_dev *rdev;

	/* assign per-regulator data */
	info = &hi6421_regulator_info[id];

	config.dev = &pdev->dev;
	config.init_data = init_data;
	config.driver_data = info;
	config.regmap = rmap;
	config.of_node = np;

	/* register regulator with framework */
	rdev = devm_regulator_register(&pdev->dev, &info->desc, &config);
	if (IS_ERR(rdev)) {
		dev_err(&pdev->dev, "failed to register regulator %s\n",
			info->desc.name);
		return PTR_ERR(rdev);
	}

	return 0;
}

static int hi6421_regulator_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np;
	struct hi6421_pmic *pmic;
	struct hi6421_regulator_pdata *pdata;
	int i, ret = 0;

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;
	mutex_init(&pdata->lock);
	platform_set_drvdata(pdev, pdata);

	np = of_get_child_by_name(dev->parent->of_node, "regulators");
	if (!np)
		return -ENODEV;

	ret = of_regulator_match(dev, np,
				 hi6421_regulator_match,
				 ARRAY_SIZE(hi6421_regulator_match));
	of_node_put(np);
	if (ret < 0) {
		dev_err(dev, "Error parsing regulator init data: %d\n", ret);
		return ret;
	}

	pmic = dev_get_drvdata(dev->parent);

	for (i = 0; i < ARRAY_SIZE(hi6421_regulator_info); i++) {
		ret = hi6421_regulator_register(pdev, pmic->regmap,
			hi6421_regulator_match[i].init_data, i,
			hi6421_regulator_match[i].of_node);
		if (ret)
			return ret;
	}

	return 0;
}

static const struct platform_device_id hi6421_regulator_table[] = {
	{ .name = "hi6421-regulator" },
	{},
};
MODULE_DEVICE_TABLE(platform, hi6421_regulator_table);

static struct platform_driver hi6421_regulator_driver = {
	.id_table = hi6421_regulator_table,
	.driver = {
		.name	= "hi6421-regulator",
	},
	.probe	= hi6421_regulator_probe,
};
module_platform_driver(hi6421_regulator_driver);

MODULE_AUTHOR("Guodong Xu <guodong.xu@linaro.org>");
MODULE_DESCRIPTION("Hi6421 regulator driver");
MODULE_LICENSE("GPL v2");