drivers/regulator/mcp16502.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 //
 // MCP16502 PMIC driver
 //
 // Copyright (C) 2018 Microchip Technology Inc. and its subsidiaries
 //
 // Author: Andrei Stefanescu <andrei.stefanescu@microchip.com>
 //
 // Inspired from tps65086-regulator.c

 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/regmap.h>
 #include <linux/regulator/driver.h>
 #include <linux/suspend.h>
 #include <linux/gpio/consumer.h>

 #define VDD_LOW_SEL 0x0D
 #define VDD_HIGH_SEL 0x3F

 #define MCP16502_FLT		BIT(7)
 #define MCP16502_DVSR		GENMASK(3, 2)
 #define MCP16502_ENS		BIT(0)

 /*
  * The PMIC has four sets of registers corresponding to four power modes:
  * Performance, Active, Low-power, Hibernate.
  *
  * Registers:
  * Each regulator has a register for each power mode. To access a register
  * for a specific regulator and mode BASE_* and OFFSET_* need to be added.
  *
  * Operating modes:
  * In order for the PMIC to transition to operating modes it has to be
  * controlled via GPIO lines called LPM and HPM.
  *
  * The registers are fully configurable such that you can put all regulators in
  * a low-power state while the PMIC is in Active mode. They are supposed to be
  * configured at startup and then simply transition to/from a global low-power
  * state by setting the GPIO lpm pin high/low.
  *
  * This driver keeps the PMIC in Active mode, Low-power state is set for the
  * regulators by enabling/disabling operating mode (FPWM or Auto PFM).
  *
  * The PMIC's Low-power and Hibernate modes are used during standby/suspend.
  * To enter standby/suspend the PMIC will go to Low-power mode. From there, it
  * will transition to Hibernate when the PWRHLD line is set to low by the MPU.
  */

 /*
  * This function is useful for iterating over all regulators and accessing their
  * registers in a generic way or accessing a regulator device by its id.
  */
 #define MCP16502_REG_BASE(i, r) ((((i) + 1) << 4) + MCP16502_REG_##r)
 #define MCP16502_STAT_BASE(i) ((i) + 5)

 #define MCP16502_OPMODE_ACTIVE REGULATOR_MODE_NORMAL
 #define MCP16502_OPMODE_LPM REGULATOR_MODE_IDLE
 #define MCP16502_OPMODE_HIB REGULATOR_MODE_STANDBY

 #define MCP16502_MODE_AUTO_PFM 0
 #define MCP16502_MODE_FPWM BIT(6)

 #define MCP16502_VSEL 0x3F
 #define MCP16502_EN BIT(7)
 #define MCP16502_MODE BIT(6)

 #define MCP16502_MIN_REG 0x0
 #define MCP16502_MAX_REG 0x65

 /**
  * enum mcp16502_reg - MCP16502 regulators's registers
  * @MCP16502_REG_A: active state register
  * @MCP16502_REG_LPM: low power mode state register
  * @MCP16502_REG_HIB: hibernate state register
  * @MCP16502_REG_SEQ: startup sequence register
  * @MCP16502_REG_CFG: configuration register
  */
 enum mcp16502_reg {
 	MCP16502_REG_A,
 	MCP16502_REG_LPM,
 	MCP16502_REG_HIB,
 	MCP16502_REG_HPM,
 	MCP16502_REG_SEQ,
 	MCP16502_REG_CFG,
 };

 /* Ramp delay (uV/us) for buck1, ldo1, ldo2. */
 static const int mcp16502_ramp_b1l12[] = { 6250, 3125, 2083, 1563 };

 /* Ramp delay (uV/us) for buck2, buck3, buck4. */
 static const int mcp16502_ramp_b234[] = { 3125, 1563, 1042, 781 };

 static unsigned int mcp16502_of_map_mode(unsigned int mode)
 {
 	if (mode == REGULATOR_MODE_NORMAL || mode == REGULATOR_MODE_IDLE)
 		return mode;

 	return REGULATOR_MODE_INVALID;
 }

 #define MCP16502_REGULATOR(_name, _id, _ranges, _ops)			\
 	[_id] = {							\
 		.name			= _name,			\
 		.regulators_node	= of_match_ptr("regulators"),	\
 		.id			= _id,				\
 		.ops			= &(_ops),			\
 		.type			= REGULATOR_VOLTAGE,		\
 		.owner			= THIS_MODULE,			\
 		.n_voltages		= MCP16502_VSEL + 1,		\
 		.linear_ranges		= _ranges,			\
 		.linear_min_sel		= VDD_LOW_SEL,			\
 		.n_linear_ranges	= ARRAY_SIZE(_ranges),		\
 		.of_match		= of_match_ptr(_name),		\
 		.of_map_mode		= mcp16502_of_map_mode,		\
 		.vsel_reg		= (((_id) + 1) << 4),		\
 		.vsel_mask		= MCP16502_VSEL,		\
 		.enable_reg		= (((_id) + 1) << 4),		\
 		.enable_mask		= MCP16502_EN,			\
 	}

 enum {
 	BUCK1 = 0,
 	BUCK2,
 	BUCK3,
 	BUCK4,
 	LDO1,
 	LDO2,
 	NUM_REGULATORS
 };

 /*
  * struct mcp16502 - PMIC representation
  * @lpm: LPM GPIO descriptor
  */
 struct mcp16502 {
 	struct gpio_desc *lpm;
 };

 /*
  * mcp16502_gpio_set_mode() - set the GPIO corresponding value
  *
  * Used to prepare transitioning into hibernate or resuming from it.
  */
 static void mcp16502_gpio_set_mode(struct mcp16502 *mcp, int mode)
 {
 	switch (mode) {
 	case MCP16502_OPMODE_ACTIVE:
 		gpiod_set_value(mcp->lpm, 0);
 		break;
 	case MCP16502_OPMODE_LPM:
 	case MCP16502_OPMODE_HIB:
 		gpiod_set_value(mcp->lpm, 1);
 		break;
 	default:
 		pr_err("%s: %d invalid\n", __func__, mode);
 	}
 }

 /*
  * mcp16502_get_reg() - get the PMIC's state configuration register for opmode
  *
  * @rdev: the regulator whose register we are searching
  * @opmode: the PMIC's operating mode ACTIVE, Low-power, Hibernate
  */
 static int mcp16502_get_state_reg(struct regulator_dev *rdev, int opmode)
 {
 	switch (opmode) {
 	case MCP16502_OPMODE_ACTIVE:
 		return MCP16502_REG_BASE(rdev_get_id(rdev), A);
 	case MCP16502_OPMODE_LPM:
 		return MCP16502_REG_BASE(rdev_get_id(rdev), LPM);
 	case MCP16502_OPMODE_HIB:
 		return MCP16502_REG_BASE(rdev_get_id(rdev), HIB);
 	default:
 		return -EINVAL;
 	}
 }

 /*
  * mcp16502_get_mode() - return the current operating mode of a regulator
  *
  * Note: all functions that are not part of entering/exiting standby/suspend
  *	 use the Active mode registers.
  *
  * Note: this is different from the PMIC's operatig mode, it is the
  *	 MODE bit from the regulator's register.
  */
 static unsigned int mcp16502_get_mode(struct regulator_dev *rdev)
 {
 	unsigned int val;
 	int ret, reg;

 	reg = mcp16502_get_state_reg(rdev, MCP16502_OPMODE_ACTIVE);
 	if (reg < 0)
 		return reg;

 	ret = regmap_read(rdev->regmap, reg, &val);
 	if (ret)
 		return ret;

 	switch (val & MCP16502_MODE) {
 	case MCP16502_MODE_FPWM:
 		return REGULATOR_MODE_NORMAL;
 	case MCP16502_MODE_AUTO_PFM:
 		return REGULATOR_MODE_IDLE;
 	default:
 		return REGULATOR_MODE_INVALID;
 	}
 }

 /*
  * _mcp16502_set_mode() - helper for set_mode and set_suspend_mode
  *
  * @rdev: the regulator for which we are setting the mode
  * @mode: the regulator's mode (the one from MODE bit)
  * @opmode: the PMIC's operating mode: Active/Low-power/Hibernate
  */
 static int _mcp16502_set_mode(struct regulator_dev *rdev, unsigned int mode,
 			      unsigned int op_mode)
 {
 	int val;
 	int reg;

 	reg = mcp16502_get_state_reg(rdev, op_mode);
 	if (reg < 0)
 		return reg;

 	switch (mode) {
 	case REGULATOR_MODE_NORMAL:
 		val = MCP16502_MODE_FPWM;
 		break;
 	case REGULATOR_MODE_IDLE:
 		val = MCP16502_MODE_AUTO_PFM;
 		break;
 	default:
 		return -EINVAL;
 	}

 	reg = regmap_update_bits(rdev->regmap, reg, MCP16502_MODE, val);
 	return reg;
 }

 /*
  * mcp16502_set_mode() - regulator_ops set_mode
  */
 static int mcp16502_set_mode(struct regulator_dev *rdev, unsigned int mode)
 {
 	return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_ACTIVE);
 }

 /*
  * mcp16502_get_status() - regulator_ops get_status
  */
 static int mcp16502_get_status(struct regulator_dev *rdev)
 {
 	int ret;
 	unsigned int val;

 	ret = regmap_read(rdev->regmap, MCP16502_STAT_BASE(rdev_get_id(rdev)),
 			  &val);
 	if (ret)
 		return ret;

 	if (val & MCP16502_FLT)
 		return REGULATOR_STATUS_ERROR;
 	else if (val & MCP16502_ENS)
 		return REGULATOR_STATUS_ON;
 	else if (!(val & MCP16502_ENS))
 		return REGULATOR_STATUS_OFF;

 	return REGULATOR_STATUS_UNDEFINED;
 }

 static int mcp16502_set_voltage_time_sel(struct regulator_dev *rdev,
 					 unsigned int old_sel,
 					 unsigned int new_sel)
 {
 	static const u8 us_ramp[] = { 8, 16, 24, 32 };
 	int id = rdev_get_id(rdev);
 	unsigned int uV_delta, val;
 	int ret;

 	ret = regmap_read(rdev->regmap, MCP16502_REG_BASE(id, CFG), &val);
 	if (ret)
 		return ret;

 	val = (val & MCP16502_DVSR) >> 2;
 	uV_delta = abs(new_sel * rdev->desc->linear_ranges->step -
 		       old_sel * rdev->desc->linear_ranges->step);
 	switch (id) {
 	case BUCK1:
 	case LDO1:
 	case LDO2:
 		ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
 					mcp16502_ramp_b1l12[val]);
 		break;

 	case BUCK2:
 	case BUCK3:
 	case BUCK4:
 		ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
 					mcp16502_ramp_b234[val]);
 		break;

 	default:
 		return -EINVAL;
 	}

 	return ret;
 }

 static int mcp16502_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
 {
 	const int *ramp;
 	int id = rdev_get_id(rdev);
 	unsigned int i, size;

 	switch (id) {
 	case BUCK1:
 	case LDO1:
 	case LDO2:
 		ramp = mcp16502_ramp_b1l12;
 		size = ARRAY_SIZE(mcp16502_ramp_b1l12);
 		break;

 	case BUCK2:
 	case BUCK3:
 	case BUCK4:
 		ramp = mcp16502_ramp_b234;
 		size = ARRAY_SIZE(mcp16502_ramp_b234);
 		break;

 	default:
 		return -EINVAL;
 	}

 	for (i = 0; i < size; i++) {
 		if (ramp[i] == ramp_delay)
 			break;
 	}
 	if (i == size)
 		return -EINVAL;

 	return regmap_update_bits(rdev->regmap, MCP16502_REG_BASE(id, CFG),
 				  MCP16502_DVSR, (i << 2));
 }

 #ifdef CONFIG_SUSPEND
 /*
  * mcp16502_suspend_get_target_reg() - get the reg of the target suspend PMIC
  *				       mode
  */
 static int mcp16502_suspend_get_target_reg(struct regulator_dev *rdev)
 {
 	switch (pm_suspend_target_state) {
 	case PM_SUSPEND_STANDBY:
 		return mcp16502_get_state_reg(rdev, MCP16502_OPMODE_LPM);
 	case PM_SUSPEND_ON:
 	case PM_SUSPEND_MEM:
 		return mcp16502_get_state_reg(rdev, MCP16502_OPMODE_HIB);
 	default:
 		dev_err(&rdev->dev, "invalid suspend target: %d\n",
 			pm_suspend_target_state);
 	}

 	return -EINVAL;
 }

 /*
  * mcp16502_set_suspend_voltage() - regulator_ops set_suspend_voltage
  */
 static int mcp16502_set_suspend_voltage(struct regulator_dev *rdev, int uV)
 {
 	int sel = regulator_map_voltage_linear_range(rdev, uV, uV);
 	int reg = mcp16502_suspend_get_target_reg(rdev);

 	if (sel < 0)
 		return sel;

 	if (reg < 0)
 		return reg;

 	return regmap_update_bits(rdev->regmap, reg, MCP16502_VSEL, sel);
 }

 /*
  * mcp16502_set_suspend_mode() - regulator_ops set_suspend_mode
  */
 static int mcp16502_set_suspend_mode(struct regulator_dev *rdev,
 				     unsigned int mode)
 {
 	switch (pm_suspend_target_state) {
 	case PM_SUSPEND_STANDBY:
 		return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_LPM);
 	case PM_SUSPEND_ON:
 	case PM_SUSPEND_MEM:
 		return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_HIB);
 	default:
 		dev_err(&rdev->dev, "invalid suspend target: %d\n",
 			pm_suspend_target_state);
 	}

 	return -EINVAL;
 }

 /*
  * mcp16502_set_suspend_enable() - regulator_ops set_suspend_enable
  */
 static int mcp16502_set_suspend_enable(struct regulator_dev *rdev)
 {
 	int reg = mcp16502_suspend_get_target_reg(rdev);

 	if (reg < 0)
 		return reg;

 	return regmap_update_bits(rdev->regmap, reg, MCP16502_EN, MCP16502_EN);
 }

 /*
  * mcp16502_set_suspend_disable() - regulator_ops set_suspend_disable
  */
 static int mcp16502_set_suspend_disable(struct regulator_dev *rdev)
 {
 	int reg = mcp16502_suspend_get_target_reg(rdev);

 	if (reg < 0)
 		return reg;

 	return regmap_update_bits(rdev->regmap, reg, MCP16502_EN, 0);
 }
 #endif /* CONFIG_SUSPEND */

 static const struct regulator_ops mcp16502_buck_ops = {
 	.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,
 	.enable				= regulator_enable_regmap,
 	.disable			= regulator_disable_regmap,
 	.is_enabled			= regulator_is_enabled_regmap,
 	.get_status			= mcp16502_get_status,
 	.set_voltage_time_sel		= mcp16502_set_voltage_time_sel,
 	.set_ramp_delay			= mcp16502_set_ramp_delay,

 	.set_mode			= mcp16502_set_mode,
 	.get_mode			= mcp16502_get_mode,

 #ifdef CONFIG_SUSPEND
 	.set_suspend_voltage		= mcp16502_set_suspend_voltage,
 	.set_suspend_mode		= mcp16502_set_suspend_mode,
 	.set_suspend_enable		= mcp16502_set_suspend_enable,
 	.set_suspend_disable		= mcp16502_set_suspend_disable,
 #endif /* CONFIG_SUSPEND */
 };

 /*
  * LDOs cannot change operating modes.
  */
 static const struct regulator_ops mcp16502_ldo_ops = {
 	.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,
 	.enable				= regulator_enable_regmap,
 	.disable			= regulator_disable_regmap,
 	.is_enabled			= regulator_is_enabled_regmap,
 	.get_status			= mcp16502_get_status,
 	.set_voltage_time_sel		= mcp16502_set_voltage_time_sel,
 	.set_ramp_delay			= mcp16502_set_ramp_delay,

 #ifdef CONFIG_SUSPEND
 	.set_suspend_voltage		= mcp16502_set_suspend_voltage,
 	.set_suspend_enable		= mcp16502_set_suspend_enable,
 	.set_suspend_disable		= mcp16502_set_suspend_disable,
 #endif /* CONFIG_SUSPEND */
 };

 static const struct of_device_id mcp16502_ids[] = {
 	{ .compatible = "microchip,mcp16502", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, mcp16502_ids);

 static const struct linear_range b1l12_ranges[] = {
 	REGULATOR_LINEAR_RANGE(1200000, VDD_LOW_SEL, VDD_HIGH_SEL, 50000),
 };

 static const struct linear_range b234_ranges[] = {
 	REGULATOR_LINEAR_RANGE(600000, VDD_LOW_SEL, VDD_HIGH_SEL, 25000),
 };

 static const struct regulator_desc mcp16502_desc[] = {
 	/* MCP16502_REGULATOR(_name, _id, ranges, regulator_ops) */
 	MCP16502_REGULATOR("VDD_IO", BUCK1, b1l12_ranges, mcp16502_buck_ops),
 	MCP16502_REGULATOR("VDD_DDR", BUCK2, b234_ranges, mcp16502_buck_ops),
 	MCP16502_REGULATOR("VDD_CORE", BUCK3, b234_ranges, mcp16502_buck_ops),
 	MCP16502_REGULATOR("VDD_OTHER", BUCK4, b234_ranges, mcp16502_buck_ops),
 	MCP16502_REGULATOR("LDO1", LDO1, b1l12_ranges, mcp16502_ldo_ops),
 	MCP16502_REGULATOR("LDO2", LDO2, b1l12_ranges, mcp16502_ldo_ops)
 };

 static const struct regmap_range mcp16502_ranges[] = {
 	regmap_reg_range(MCP16502_MIN_REG, MCP16502_MAX_REG)
 };

 static const struct regmap_access_table mcp16502_yes_reg_table = {
 	.yes_ranges = mcp16502_ranges,
 	.n_yes_ranges = ARRAY_SIZE(mcp16502_ranges),
 };

 static const struct regmap_config mcp16502_regmap_config = {
 	.reg_bits	= 8,
 	.val_bits	= 8,
 	.max_register	= MCP16502_MAX_REG,
 	.cache_type	= REGCACHE_NONE,
 	.rd_table	= &mcp16502_yes_reg_table,
 	.wr_table	= &mcp16502_yes_reg_table,
 };

 static int mcp16502_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	struct regulator_config config = { };
 	struct regulator_dev *rdev;
 	struct device *dev;
 	struct mcp16502 *mcp;
 	struct regmap *rmap;
 	int i, ret;

 	dev = &client->dev;
 	config.dev = dev;

 	mcp = devm_kzalloc(dev, sizeof(*mcp), GFP_KERNEL);
 	if (!mcp)
 		return -ENOMEM;

 	rmap = devm_regmap_init_i2c(client, &mcp16502_regmap_config);
 	if (IS_ERR(rmap)) {
 		ret = PTR_ERR(rmap);
 		dev_err(dev, "regmap init failed: %d\n", ret);
 		return ret;
 	}

 	i2c_set_clientdata(client, mcp);
 	config.regmap = rmap;
 	config.driver_data = mcp;

 	mcp->lpm = devm_gpiod_get_optional(dev, "lpm", GPIOD_OUT_LOW);
 	if (IS_ERR(mcp->lpm)) {
 		dev_err(dev, "failed to get lpm pin: %ld\n", PTR_ERR(mcp->lpm));
 		return PTR_ERR(mcp->lpm);
 	}

 	for (i = 0; i < NUM_REGULATORS; i++) {
 		rdev = devm_regulator_register(dev, &mcp16502_desc[i], &config);
 		if (IS_ERR(rdev)) {
 			dev_err(dev,
 				"failed to register %s regulator %ld\n",
 				mcp16502_desc[i].name, PTR_ERR(rdev));
 			return PTR_ERR(rdev);
 		}
 	}

 	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_ACTIVE);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int mcp16502_suspend_noirq(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct mcp16502 *mcp = i2c_get_clientdata(client);

 	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_LPM);

 	return 0;
 }

 static int mcp16502_resume_noirq(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct mcp16502 *mcp = i2c_get_clientdata(client);

 	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_ACTIVE);

 	return 0;
 }
 #endif

 #ifdef CONFIG_PM
 static const struct dev_pm_ops mcp16502_pm_ops = {
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mcp16502_suspend_noirq,
 				      mcp16502_resume_noirq)
 };
 #endif
 static const struct i2c_device_id mcp16502_i2c_id[] = {
 	{ "mcp16502", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mcp16502_i2c_id);

 static struct i2c_driver mcp16502_drv = {
 	.probe		= mcp16502_probe,
 	.driver		= {
 		.name	= "mcp16502-regulator",
 		.of_match_table	= of_match_ptr(mcp16502_ids),
 #ifdef CONFIG_PM
 		.pm = &mcp16502_pm_ops,
 #endif
 	},
 	.id_table	= mcp16502_i2c_id,
 };

 module_i2c_driver(mcp16502_drv);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("MCP16502 PMIC driver");
 MODULE_AUTHOR("Andrei Stefanescu andrei.stefanescu@microchip.com");
	// SPDX-License-Identifier: GPL-2.0
	//
	// MCP16502 PMIC driver
	//
	// Copyright (C) 2018 Microchip Technology Inc. and its subsidiaries
	//
	// Author: Andrei Stefanescu <andrei.stefanescu@microchip.com>
	//
	// Inspired from tps65086-regulator.c

	#include <linux/gpio.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/regmap.h>
	#include <linux/regulator/driver.h>
	#include <linux/suspend.h>
	#include <linux/gpio/consumer.h>

	#define VDD_LOW_SEL 0x0D
	#define VDD_HIGH_SEL 0x3F

	#define MCP16502_FLT BIT(7)
	#define MCP16502_DVSR GENMASK(3, 2)
	#define MCP16502_ENS BIT(0)

	/*
	* The PMIC has four sets of registers corresponding to four power modes:
	* Performance, Active, Low-power, Hibernate.
	*
	* Registers:
	* Each regulator has a register for each power mode. To access a register
	* for a specific regulator and mode BASE_* and OFFSET_* need to be added.
	*
	* Operating modes:
	* In order for the PMIC to transition to operating modes it has to be
	* controlled via GPIO lines called LPM and HPM.
	*
	* The registers are fully configurable such that you can put all regulators in
	* a low-power state while the PMIC is in Active mode. They are supposed to be
	* configured at startup and then simply transition to/from a global low-power
	* state by setting the GPIO lpm pin high/low.
	*
	* This driver keeps the PMIC in Active mode, Low-power state is set for the
	* regulators by enabling/disabling operating mode (FPWM or Auto PFM).
	*
	* The PMIC's Low-power and Hibernate modes are used during standby/suspend.
	* To enter standby/suspend the PMIC will go to Low-power mode. From there, it
	* will transition to Hibernate when the PWRHLD line is set to low by the MPU.
	*/

	/*
	* This function is useful for iterating over all regulators and accessing their
	* registers in a generic way or accessing a regulator device by its id.
	*/
	#define MCP16502_REG_BASE(i, r) ((((i) + 1) << 4) + MCP16502_REG_##r)
	#define MCP16502_STAT_BASE(i) ((i) + 5)

	#define MCP16502_OPMODE_ACTIVE REGULATOR_MODE_NORMAL
	#define MCP16502_OPMODE_LPM REGULATOR_MODE_IDLE
	#define MCP16502_OPMODE_HIB REGULATOR_MODE_STANDBY

	#define MCP16502_MODE_AUTO_PFM 0
	#define MCP16502_MODE_FPWM BIT(6)

	#define MCP16502_VSEL 0x3F
	#define MCP16502_EN BIT(7)
	#define MCP16502_MODE BIT(6)

	#define MCP16502_MIN_REG 0x0
	#define MCP16502_MAX_REG 0x65

	/**
	* enum mcp16502_reg - MCP16502 regulators's registers
	* @MCP16502_REG_A: active state register
	* @MCP16502_REG_LPM: low power mode state register
	* @MCP16502_REG_HIB: hibernate state register
	* @MCP16502_REG_SEQ: startup sequence register
	* @MCP16502_REG_CFG: configuration register
	*/
	enum mcp16502_reg {
	MCP16502_REG_A,
	MCP16502_REG_LPM,
	MCP16502_REG_HIB,
	MCP16502_REG_HPM,
	MCP16502_REG_SEQ,
	MCP16502_REG_CFG,
	};

	/* Ramp delay (uV/us) for buck1, ldo1, ldo2. */
	static const int mcp16502_ramp_b1l12[] = { 6250, 3125, 2083, 1563 };

	/* Ramp delay (uV/us) for buck2, buck3, buck4. */
	static const int mcp16502_ramp_b234[] = { 3125, 1563, 1042, 781 };

	static unsigned int mcp16502_of_map_mode(unsigned int mode)
	{
	if (mode == REGULATOR_MODE_NORMAL \|\| mode == REGULATOR_MODE_IDLE)
	return mode;

	return REGULATOR_MODE_INVALID;
	}

	#define MCP16502_REGULATOR(_name, _id, _ranges, _ops) \
	[_id] = { \
	.name = _name, \
	.regulators_node = of_match_ptr("regulators"), \
	.id = _id, \
	.ops = &(_ops), \
	.type = REGULATOR_VOLTAGE, \
	.owner = THIS_MODULE, \
	.n_voltages = MCP16502_VSEL + 1, \
	.linear_ranges = _ranges, \
	.linear_min_sel = VDD_LOW_SEL, \
	.n_linear_ranges = ARRAY_SIZE(_ranges), \
	.of_match = of_match_ptr(_name), \
	.of_map_mode = mcp16502_of_map_mode, \
	.vsel_reg = (((_id) + 1) << 4), \
	.vsel_mask = MCP16502_VSEL, \
	.enable_reg = (((_id) + 1) << 4), \
	.enable_mask = MCP16502_EN, \
	}

	enum {
	BUCK1 = 0,
	BUCK2,
	BUCK3,
	BUCK4,
	LDO1,
	LDO2,
	NUM_REGULATORS
	};

	/*
	* struct mcp16502 - PMIC representation
	* @lpm: LPM GPIO descriptor
	*/
	struct mcp16502 {
	struct gpio_desc *lpm;
	};

	/*
	* mcp16502_gpio_set_mode() - set the GPIO corresponding value
	*
	* Used to prepare transitioning into hibernate or resuming from it.
	*/
	static void mcp16502_gpio_set_mode(struct mcp16502 *mcp, int mode)
	{
	switch (mode) {
	case MCP16502_OPMODE_ACTIVE:
	gpiod_set_value(mcp->lpm, 0);
	break;
	case MCP16502_OPMODE_LPM:
	case MCP16502_OPMODE_HIB:
	gpiod_set_value(mcp->lpm, 1);
	break;
	default:
	pr_err("%s: %d invalid\n", __func__, mode);
	}
	}

	/*
	* mcp16502_get_reg() - get the PMIC's state configuration register for opmode
	*
	* @rdev: the regulator whose register we are searching
	* @opmode: the PMIC's operating mode ACTIVE, Low-power, Hibernate
	*/
	static int mcp16502_get_state_reg(struct regulator_dev *rdev, int opmode)
	{
	switch (opmode) {
	case MCP16502_OPMODE_ACTIVE:
	return MCP16502_REG_BASE(rdev_get_id(rdev), A);
	case MCP16502_OPMODE_LPM:
	return MCP16502_REG_BASE(rdev_get_id(rdev), LPM);
	case MCP16502_OPMODE_HIB:
	return MCP16502_REG_BASE(rdev_get_id(rdev), HIB);
	default:
	return -EINVAL;
	}
	}

	/*
	* mcp16502_get_mode() - return the current operating mode of a regulator
	*
	* Note: all functions that are not part of entering/exiting standby/suspend
	* use the Active mode registers.
	*
	* Note: this is different from the PMIC's operatig mode, it is the
	* MODE bit from the regulator's register.
	*/
	static unsigned int mcp16502_get_mode(struct regulator_dev *rdev)
	{
	unsigned int val;
	int ret, reg;

	reg = mcp16502_get_state_reg(rdev, MCP16502_OPMODE_ACTIVE);
	if (reg < 0)
	return reg;

	ret = regmap_read(rdev->regmap, reg, &val);
	if (ret)
	return ret;

	switch (val & MCP16502_MODE) {
	case MCP16502_MODE_FPWM:
	return REGULATOR_MODE_NORMAL;
	case MCP16502_MODE_AUTO_PFM:
	return REGULATOR_MODE_IDLE;
	default:
	return REGULATOR_MODE_INVALID;
	}
	}

	/*
	* _mcp16502_set_mode() - helper for set_mode and set_suspend_mode
	*
	* @rdev: the regulator for which we are setting the mode
	* @mode: the regulator's mode (the one from MODE bit)
	* @opmode: the PMIC's operating mode: Active/Low-power/Hibernate
	*/
	static int _mcp16502_set_mode(struct regulator_dev *rdev, unsigned int mode,
	unsigned int op_mode)
	{
	int val;
	int reg;

	reg = mcp16502_get_state_reg(rdev, op_mode);
	if (reg < 0)
	return reg;

	switch (mode) {
	case REGULATOR_MODE_NORMAL:
	val = MCP16502_MODE_FPWM;
	break;
	case REGULATOR_MODE_IDLE:
	val = MCP16502_MODE_AUTO_PFM;
	break;
	default:
	return -EINVAL;
	}

	reg = regmap_update_bits(rdev->regmap, reg, MCP16502_MODE, val);
	return reg;
	}

	/*
	* mcp16502_set_mode() - regulator_ops set_mode
	*/
	static int mcp16502_set_mode(struct regulator_dev *rdev, unsigned int mode)
	{
	return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_ACTIVE);
	}

	/*
	* mcp16502_get_status() - regulator_ops get_status
	*/
	static int mcp16502_get_status(struct regulator_dev *rdev)
	{
	int ret;
	unsigned int val;

	ret = regmap_read(rdev->regmap, MCP16502_STAT_BASE(rdev_get_id(rdev)),
	&val);
	if (ret)
	return ret;

	if (val & MCP16502_FLT)
	return REGULATOR_STATUS_ERROR;
	else if (val & MCP16502_ENS)
	return REGULATOR_STATUS_ON;
	else if (!(val & MCP16502_ENS))
	return REGULATOR_STATUS_OFF;

	return REGULATOR_STATUS_UNDEFINED;
	}

	static int mcp16502_set_voltage_time_sel(struct regulator_dev *rdev,
	unsigned int old_sel,
	unsigned int new_sel)
	{
	static const u8 us_ramp[] = { 8, 16, 24, 32 };
	int id = rdev_get_id(rdev);
	unsigned int uV_delta, val;
	int ret;

	ret = regmap_read(rdev->regmap, MCP16502_REG_BASE(id, CFG), &val);
	if (ret)
	return ret;

	val = (val & MCP16502_DVSR) >> 2;
	uV_delta = abs(new_sel * rdev->desc->linear_ranges->step -
	old_sel * rdev->desc->linear_ranges->step);
	switch (id) {
	case BUCK1:
	case LDO1:
	case LDO2:
	ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
	mcp16502_ramp_b1l12[val]);
	break;

	case BUCK2:
	case BUCK3:
	case BUCK4:
	ret = DIV_ROUND_CLOSEST(uV_delta * us_ramp[val],
	mcp16502_ramp_b234[val]);
	break;

	default:
	return -EINVAL;
	}

	return ret;
	}

	static int mcp16502_set_ramp_delay(struct regulator_dev *rdev, int ramp_delay)
	{
	const int *ramp;
	int id = rdev_get_id(rdev);
	unsigned int i, size;

	switch (id) {
	case BUCK1:
	case LDO1:
	case LDO2:
	ramp = mcp16502_ramp_b1l12;
	size = ARRAY_SIZE(mcp16502_ramp_b1l12);
	break;

	case BUCK2:
	case BUCK3:
	case BUCK4:
	ramp = mcp16502_ramp_b234;
	size = ARRAY_SIZE(mcp16502_ramp_b234);
	break;

	default:
	return -EINVAL;
	}

	for (i = 0; i < size; i++) {
	if (ramp[i] == ramp_delay)
	break;
	}
	if (i == size)
	return -EINVAL;

	return regmap_update_bits(rdev->regmap, MCP16502_REG_BASE(id, CFG),
	MCP16502_DVSR, (i << 2));
	}

	#ifdef CONFIG_SUSPEND
	/*
	* mcp16502_suspend_get_target_reg() - get the reg of the target suspend PMIC
	* mode
	*/
	static int mcp16502_suspend_get_target_reg(struct regulator_dev *rdev)
	{
	switch (pm_suspend_target_state) {
	case PM_SUSPEND_STANDBY:
	return mcp16502_get_state_reg(rdev, MCP16502_OPMODE_LPM);
	case PM_SUSPEND_ON:
	case PM_SUSPEND_MEM:
	return mcp16502_get_state_reg(rdev, MCP16502_OPMODE_HIB);
	default:
	dev_err(&rdev->dev, "invalid suspend target: %d\n",
	pm_suspend_target_state);
	}

	return -EINVAL;
	}

	/*
	* mcp16502_set_suspend_voltage() - regulator_ops set_suspend_voltage
	*/
	static int mcp16502_set_suspend_voltage(struct regulator_dev *rdev, int uV)
	{
	int sel = regulator_map_voltage_linear_range(rdev, uV, uV);
	int reg = mcp16502_suspend_get_target_reg(rdev);

	if (sel < 0)
	return sel;

	if (reg < 0)
	return reg;

	return regmap_update_bits(rdev->regmap, reg, MCP16502_VSEL, sel);
	}

	/*
	* mcp16502_set_suspend_mode() - regulator_ops set_suspend_mode
	*/
	static int mcp16502_set_suspend_mode(struct regulator_dev *rdev,
	unsigned int mode)
	{
	switch (pm_suspend_target_state) {
	case PM_SUSPEND_STANDBY:
	return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_LPM);
	case PM_SUSPEND_ON:
	case PM_SUSPEND_MEM:
	return _mcp16502_set_mode(rdev, mode, MCP16502_OPMODE_HIB);
	default:
	dev_err(&rdev->dev, "invalid suspend target: %d\n",
	pm_suspend_target_state);
	}

	return -EINVAL;
	}

	/*
	* mcp16502_set_suspend_enable() - regulator_ops set_suspend_enable
	*/
	static int mcp16502_set_suspend_enable(struct regulator_dev *rdev)
	{
	int reg = mcp16502_suspend_get_target_reg(rdev);

	if (reg < 0)
	return reg;

	return regmap_update_bits(rdev->regmap, reg, MCP16502_EN, MCP16502_EN);
	}

	/*
	* mcp16502_set_suspend_disable() - regulator_ops set_suspend_disable
	*/
	static int mcp16502_set_suspend_disable(struct regulator_dev *rdev)
	{
	int reg = mcp16502_suspend_get_target_reg(rdev);

	if (reg < 0)
	return reg;

	return regmap_update_bits(rdev->regmap, reg, MCP16502_EN, 0);
	}
	#endif /* CONFIG_SUSPEND */

	static const struct regulator_ops mcp16502_buck_ops = {
	.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,
	.enable = regulator_enable_regmap,
	.disable = regulator_disable_regmap,
	.is_enabled = regulator_is_enabled_regmap,
	.get_status = mcp16502_get_status,
	.set_voltage_time_sel = mcp16502_set_voltage_time_sel,
	.set_ramp_delay = mcp16502_set_ramp_delay,

	.set_mode = mcp16502_set_mode,
	.get_mode = mcp16502_get_mode,

	#ifdef CONFIG_SUSPEND
	.set_suspend_voltage = mcp16502_set_suspend_voltage,
	.set_suspend_mode = mcp16502_set_suspend_mode,
	.set_suspend_enable = mcp16502_set_suspend_enable,
	.set_suspend_disable = mcp16502_set_suspend_disable,
	#endif /* CONFIG_SUSPEND */
	};

	/*
	* LDOs cannot change operating modes.
	*/
	static const struct regulator_ops mcp16502_ldo_ops = {
	.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,
	.enable = regulator_enable_regmap,
	.disable = regulator_disable_regmap,
	.is_enabled = regulator_is_enabled_regmap,
	.get_status = mcp16502_get_status,
	.set_voltage_time_sel = mcp16502_set_voltage_time_sel,
	.set_ramp_delay = mcp16502_set_ramp_delay,

	#ifdef CONFIG_SUSPEND
	.set_suspend_voltage = mcp16502_set_suspend_voltage,
	.set_suspend_enable = mcp16502_set_suspend_enable,
	.set_suspend_disable = mcp16502_set_suspend_disable,
	#endif /* CONFIG_SUSPEND */
	};

	static const struct of_device_id mcp16502_ids[] = {
	{ .compatible = "microchip,mcp16502", },
	{}
	};
	MODULE_DEVICE_TABLE(of, mcp16502_ids);

	static const struct linear_range b1l12_ranges[] = {
	REGULATOR_LINEAR_RANGE(1200000, VDD_LOW_SEL, VDD_HIGH_SEL, 50000),
	};

	static const struct linear_range b234_ranges[] = {
	REGULATOR_LINEAR_RANGE(600000, VDD_LOW_SEL, VDD_HIGH_SEL, 25000),
	};

	static const struct regulator_desc mcp16502_desc[] = {
	/* MCP16502_REGULATOR(_name, _id, ranges, regulator_ops) */
	MCP16502_REGULATOR("VDD_IO", BUCK1, b1l12_ranges, mcp16502_buck_ops),
	MCP16502_REGULATOR("VDD_DDR", BUCK2, b234_ranges, mcp16502_buck_ops),
	MCP16502_REGULATOR("VDD_CORE", BUCK3, b234_ranges, mcp16502_buck_ops),
	MCP16502_REGULATOR("VDD_OTHER", BUCK4, b234_ranges, mcp16502_buck_ops),
	MCP16502_REGULATOR("LDO1", LDO1, b1l12_ranges, mcp16502_ldo_ops),
	MCP16502_REGULATOR("LDO2", LDO2, b1l12_ranges, mcp16502_ldo_ops)
	};

	static const struct regmap_range mcp16502_ranges[] = {
	regmap_reg_range(MCP16502_MIN_REG, MCP16502_MAX_REG)
	};

	static const struct regmap_access_table mcp16502_yes_reg_table = {
	.yes_ranges = mcp16502_ranges,
	.n_yes_ranges = ARRAY_SIZE(mcp16502_ranges),
	};

	static const struct regmap_config mcp16502_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = MCP16502_MAX_REG,
	.cache_type = REGCACHE_NONE,
	.rd_table = &mcp16502_yes_reg_table,
	.wr_table = &mcp16502_yes_reg_table,
	};

	static int mcp16502_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct regulator_config config = { };
	struct regulator_dev *rdev;
	struct device *dev;
	struct mcp16502 *mcp;
	struct regmap *rmap;
	int i, ret;

	dev = &client->dev;
	config.dev = dev;

	mcp = devm_kzalloc(dev, sizeof(*mcp), GFP_KERNEL);
	if (!mcp)
	return -ENOMEM;

	rmap = devm_regmap_init_i2c(client, &mcp16502_regmap_config);
	if (IS_ERR(rmap)) {
	ret = PTR_ERR(rmap);
	dev_err(dev, "regmap init failed: %d\n", ret);
	return ret;
	}

	i2c_set_clientdata(client, mcp);
	config.regmap = rmap;
	config.driver_data = mcp;

	mcp->lpm = devm_gpiod_get_optional(dev, "lpm", GPIOD_OUT_LOW);
	if (IS_ERR(mcp->lpm)) {
	dev_err(dev, "failed to get lpm pin: %ld\n", PTR_ERR(mcp->lpm));
	return PTR_ERR(mcp->lpm);
	}

	for (i = 0; i < NUM_REGULATORS; i++) {
	rdev = devm_regulator_register(dev, &mcp16502_desc[i], &config);
	if (IS_ERR(rdev)) {
	dev_err(dev,
	"failed to register %s regulator %ld\n",
	mcp16502_desc[i].name, PTR_ERR(rdev));
	return PTR_ERR(rdev);
	}
	}

	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_ACTIVE);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int mcp16502_suspend_noirq(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct mcp16502 *mcp = i2c_get_clientdata(client);

	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_LPM);

	return 0;
	}

	static int mcp16502_resume_noirq(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct mcp16502 *mcp = i2c_get_clientdata(client);

	mcp16502_gpio_set_mode(mcp, MCP16502_OPMODE_ACTIVE);

	return 0;
	}
	#endif

	#ifdef CONFIG_PM
	static const struct dev_pm_ops mcp16502_pm_ops = {
	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(mcp16502_suspend_noirq,
	mcp16502_resume_noirq)
	};
	#endif
	static const struct i2c_device_id mcp16502_i2c_id[] = {
	{ "mcp16502", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, mcp16502_i2c_id);

	static struct i2c_driver mcp16502_drv = {
	.probe = mcp16502_probe,
	.driver = {
	.name = "mcp16502-regulator",
	.of_match_table = of_match_ptr(mcp16502_ids),
	#ifdef CONFIG_PM
	.pm = &mcp16502_pm_ops,
	#endif
	},
	.id_table = mcp16502_i2c_id,
	};

	module_i2c_driver(mcp16502_drv);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("MCP16502 PMIC driver");
	MODULE_AUTHOR("Andrei Stefanescu andrei.stefanescu@microchip.com");