/*
 * Copyright (c) 2021 NXP
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @brief PMIC Regulator Driver
 * This driver implements the regulator API within Zephyr, and additionally
 * implements support for a broader API.
 */

#define DT_DRV_COMPAT regulator_pmic

#include <zephyr/kernel.h>
#include <zephyr/drivers/regulator.h>
#include <zephyr/dt-bindings/regulator/pmic_i2c.h>
#include <zephyr/drivers/i2c.h>
#include <errno.h>
#include <zephyr/logging/log.h>

LOG_MODULE_REGISTER(pmic_regulator, CONFIG_REGULATOR_LOG_LEVEL);

struct __packed voltage_range {
	int uV; /* Voltage in uV */
	int reg_val; /* Register value for voltage */
};

struct __packed current_range {
	int uA; /* Current limit in uA */
	int reg_val; /* Register value for current limit */
};

struct regulator_data {
	struct onoff_sync_service srv;
	const struct voltage_range *voltages;
	const struct current_range *current_levels;
};

struct regulator_config {
	int num_voltages;
	int num_current_levels;
	int num_modes;
	uint8_t vsel_reg;
	uint8_t vsel_mask;
	uint32_t max_uV;
	uint32_t min_uV;
	uint8_t enable_reg;
	uint8_t enable_mask;
	uint8_t enable_val;
	bool enable_inverted;
	bool boot_on;
	uint8_t ilim_reg;
	uint8_t ilim_mask;
	struct i2c_dt_spec i2c;
	uint16_t initial_mode;
	uint32_t *voltage_array;
	uint32_t *current_array;
	uint16_t *allowed_modes;
	uint8_t modesel_offset;
	uint8_t modesel_reg;
	uint8_t modesel_mask;
};

static int regulator_pmic_is_supported_voltage(const struct device *dev,
					       int min_uV, int max_uV);

/**
 * Reads a register from the PMIC
 * Returns 0 on success, or errno on error
 */
static int regulator_read_register(const struct device *dev,
	uint8_t reg, uint8_t *out)
{
	const struct regulator_config *conf = dev->config;
	int ret;

	ret = i2c_reg_read_byte_dt(&conf->i2c, reg, out);
	LOG_DBG("READ 0x%x: 0x%x", reg, *out);
	return ret;
}

/**
 * Modifies a register within the PMIC
 * Returns 0 on success, or errno on error
 */
static int regulator_modify_register(const struct device *dev,
		uint8_t reg, uint8_t reg_mask, uint8_t reg_val)
{
	const struct regulator_config *conf = dev->config;
	uint8_t reg_current;
	int rc;

	rc = regulator_read_register(dev, reg, &reg_current);
	if (rc) {
		return rc;
	}

	reg_current &= ~reg_mask;
	reg_current |= (reg_val & reg_mask);
	LOG_DBG("WRITE 0x%02X to 0x%02X at I2C addr 0x%02X", reg_current,
		reg, conf->i2c.addr);
	return i2c_reg_write_byte_dt(&conf->i2c, reg, reg_current);
}

/*
 * Internal helper function- gets the voltage from a regulator, with an
 * offset applied to the vsel_reg. Useful to support reading voltages
 * in another target mode
 */
static int regulator_get_voltage_offset(const struct device *dev, uint32_t off)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;
	int rc, i = 0;
	uint8_t raw_reg;

	rc = regulator_read_register(dev, config->vsel_reg + off, &raw_reg);
	if (rc) {
		return rc;
	}
	raw_reg &= config->vsel_mask;
	/* Locate the voltage value in the voltage table */
	while (i < config->num_voltages &&
		raw_reg != data->voltages[i].reg_val){
		i++;
	}
	if (i == config->num_voltages) {
		LOG_WRN("Regulator vsel reg has unknown value");
		return -EIO;
	}
	return data->voltages[i].uV;
}

/**
 * Internal helper function- sets the voltage for a regulator, with an
 * offset applied to the vsel_reg. Useful to support setting voltages in
 * another target mode.
 */
static int regulator_set_voltage_offset(const struct device *dev, int min_uV,
	int max_uV, uint32_t off)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;
	int i = 0;

	if (!regulator_pmic_is_supported_voltage(dev, min_uV, max_uV) ||
		min_uV > max_uV) {
		return -EINVAL;
	}
	/* Find closest supported voltage */
	while (i < config->num_voltages && min_uV > data->voltages[i].uV) {
		i++;
	}
	if (data->voltages[i].uV > max_uV) {
		LOG_DBG("Regulator could not satisfy voltage range, too narrow");
		return -EINVAL;
	}
	if (i == config->num_voltages) {
		LOG_WRN("Regulator could not locate supported voltage,"
				"but voltage is in range.");
		return -EINVAL;
	}
	LOG_DBG("Setting regulator %s to %duV", dev->name,
			data->voltages[i].uV);
	return regulator_modify_register(dev, config->vsel_reg + off,
			config->vsel_mask, data->voltages[i].reg_val);
}


/**
 * Part of the extended regulator consumer API
 * Returns the number of supported voltages
 */
static int regulator_pmic_count_voltages(const struct device *dev)
{
	const struct regulator_config *config = dev->config;

	return config->num_voltages;
}

/**
 * Part of the extended regulator consumer API
 * Counts the number of modes supported by a regulator
 */
static int regulator_pmic_count_modes(const struct device *dev)
{
	const struct regulator_config *config = dev->config;

	return config->num_modes;
}

/**
 * Part of the extended regulator consumer API
 * Returns the supported voltage in uV for a given selector value
 */
static int regulator_pmic_list_voltages(const struct device *dev,
					unsigned int selector)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;

	if (config->num_voltages <= selector) {
		return -ENODEV;
	}
	return data->voltages[selector].uV;
}

/**
 * Part of the extended regulator consumer API
 * Returns true if the regulator supports a voltage in the given range.
 */
static int regulator_pmic_is_supported_voltage(const struct device *dev,
					       int min_uV, int max_uV)
{
	const struct regulator_config *config = dev->config;

	return !((config->max_uV < min_uV) || (config->min_uV > max_uV));
}

/**
 * Part of the extended regulator consumer API
 * Sets the output voltage to the closest supported voltage value
 */
static int regulator_pmic_set_voltage(const struct device *dev, int min_uV,
				 int max_uV)
{
	return regulator_set_voltage_offset(dev, min_uV, max_uV, 0);
}


/**
 * Part of the extended regulator consumer API
 * Gets the current output voltage in uV
 */
static int regulator_pmic_get_voltage(const struct device *dev)
{
	return regulator_get_voltage_offset(dev, 0);
}

/**
 * Part of the extended regulator consumer API
 * Set the current limit for this device
 */
static int regulator_pmic_set_current_limit(const struct device *dev, int min_uA,
					    int max_uA)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;
	int i = 0;

	if (config->num_current_levels == 0) {
		/* Regulator cannot limit current */
		return -ENOTSUP;
	}
	/* Locate the desired current limit */
	while (i < config->num_current_levels &&
		min_uA > data->current_levels[i].uA) {
		i++;
	}
	if (i == config->num_current_levels ||
		data->current_levels[i].uA > max_uA) {
		return -EINVAL;
	}
	/* Set the current limit */
	return regulator_modify_register(dev, config->ilim_reg,
		config->ilim_mask, data->current_levels[i].reg_val);
}

/**
 * Part of the extended regulator consumer API
 * Gets the set current limit for the regulator
 */
static int regulator_pmic_get_current_limit(const struct device *dev)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;
	int rc, i = 0;
	uint8_t raw_reg;

	if (config->num_current_levels == 0) {
		return -ENOTSUP;
	}
	rc = regulator_read_register(dev, config->ilim_reg, &raw_reg);
	if (rc) {
		return rc;
	}
	raw_reg &= config->ilim_mask;
	while (i < config->num_current_levels &&
		data->current_levels[i].reg_val != raw_reg) {
		i++;
	}
	if (i == config->num_current_levels) {
		return -EIO;
	}
	return data->current_levels[i].uA;
}

/*
 * Part of the extended regulator consumer API.
 * sets the target voltage for a given regulator mode. This mode does
 * not need to be the active mode. This API can be used to configure
 * voltages for a mode, then the regulator can be switched to that mode
 * with the regulator_pmic_set_mode api
 */
static int regulator_pmic_set_mode_voltage(const struct device *dev,
					   uint32_t mode, uint32_t min_uV,
					   uint32_t max_uV)
{
	const struct regulator_config *config = dev->config;
	uint8_t i, sel_off;

	if (config->num_modes == 0) {
		return -ENOTSUP;
	}

	/* Search for mode ID in allowed modes. */
	for (i = 0 ; i < config->num_modes; i++) {
		if (config->allowed_modes[i] == mode) {
			break;
		}
	}
	if (i == config->num_modes) {
		/* Mode was not found */
		return -EINVAL;
	}
	sel_off = ((mode & PMIC_MODE_OFFSET_MASK) >> PMIC_MODE_OFFSET_SHIFT);
	return regulator_set_voltage_offset(dev, min_uV, max_uV, sel_off);
}

/*
 * Part of the extended regulator consumer API.
 * Disables the regulator in a given mode. Does not implement the
 * onoff service, as this is incompatible with multiple mode operation
 */
static int regulator_pmic_mode_disable(const struct device *dev, uint32_t mode)
{
	const struct regulator_config *config = dev->config;
	uint8_t i, sel_off, dis_val;

	if (config->num_modes == 0) {
		return -ENOTSUP;
	}

	/* Search for mode ID in allowed modes. */
	for (i = 0 ; i < config->num_modes; i++) {
		if (config->allowed_modes[i] == mode) {
			break;
		}
	}
	if (i == config->num_modes) {
		/* Mode was not found */
		return -EINVAL;
	}
	sel_off = ((mode & PMIC_MODE_OFFSET_MASK) >> PMIC_MODE_OFFSET_SHIFT);
	dis_val = config->enable_inverted ? config->enable_val : 0;
	return regulator_modify_register(dev, config->enable_reg + sel_off,
			config->enable_mask, dis_val);
}

/*
 * Part of the extended regulator consumer API.
 * Enables the regulator in a given mode. Does not implement the
 * onoff service, as this is incompatible with multiple mode operation
 */
static int regulator_pmic_mode_enable(const struct device *dev, uint32_t mode)
{
	const struct regulator_config *config = dev->config;
	uint8_t i, sel_off, en_val;

	if (config->num_modes == 0) {
		return -ENOTSUP;
	}

	/* Search for mode ID in allowed modes. */
	for (i = 0 ; i < config->num_modes; i++) {
		if (config->allowed_modes[i] == mode) {
			break;
		}
	}
	if (i == config->num_modes) {
		/* Mode was not found */
		return -EINVAL;
	}
	sel_off = ((mode & PMIC_MODE_OFFSET_MASK) >> PMIC_MODE_OFFSET_SHIFT);
	en_val = config->enable_inverted ? 0 : config->enable_val;
	return regulator_modify_register(dev, config->enable_reg + sel_off,
			config->enable_mask, en_val);
}

/*
 * Part of the extended regulator consumer API.
 * gets the target voltage for a given regulator mode. This mode does
 * not need to be the active mode. This API can be used to read voltages
 * from a regulator mode other than the default.
 */
static int regulator_pmic_get_mode_voltage(const struct device *dev,
					   uint32_t mode)
{
	const struct regulator_config *config = dev->config;
	uint8_t i, sel_off;

	if (config->num_modes == 0) {
		return -ENOTSUP;
	}

	/* Search for mode ID in allowed modes. */
	for (i = 0 ; i < config->num_modes; i++) {
		if (config->allowed_modes[i] == mode) {
			break;
		}
	}
	if (i == config->num_modes) {
		/* Mode was not found */
		return -EINVAL;
	}
	sel_off = ((mode & PMIC_MODE_OFFSET_MASK) >> PMIC_MODE_OFFSET_SHIFT);
	return regulator_get_voltage_offset(dev, sel_off);
}

/*
 * Part of the extended regulator consumer API
 * switches the regulator to a given mode. This API will apply a mode for
 * the regulator.
 */
static int regulator_pmic_set_mode(const struct device *dev, uint32_t mode)
{
	const struct regulator_config *config = dev->config;
	int rc;
	uint8_t i, sel_off;

	if (config->num_modes == 0) {
		return -ENOTSUP;
	}

	/* Search for mode ID in allowed modes. */
	for (i = 0 ; i < config->num_modes; i++) {
		if (config->allowed_modes[i] == mode) {
			break;
		}
	}
	if (i == config->num_modes) {
		/* Mode was not found */
		return -EINVAL;
	}
	sel_off = ((mode & PMIC_MODE_OFFSET_MASK) >> PMIC_MODE_OFFSET_SHIFT);
	/* Configure mode */
	if (mode & PMIC_MODE_FLAG_MODESEL_MULTI_REG) {
		/* Select mode with offset calculation */
		rc = regulator_modify_register(dev,
			config->modesel_reg + sel_off,
			mode & PMIC_MODE_SELECTOR_MASK, config->modesel_mask);
	} else {
		/* Select mode without offset to modesel_reg */
		rc = regulator_modify_register(dev, config->modesel_reg,
			mode & PMIC_MODE_SELECTOR_MASK, config->modesel_mask);
	}
	return rc;
}

static int regulator_pmic_enable(const struct device *dev, struct onoff_client *cli)
{
	k_spinlock_key_t key;
	int rc;
	uint8_t en_val;
	struct regulator_data *data = dev->data;
	const struct regulator_config *config = dev->config;

	LOG_DBG("Enabling regulator");
	rc = onoff_sync_lock(&data->srv, &key);
	if (rc) {
		/* Request has already enabled PMIC */
		return onoff_sync_finalize(&data->srv, key, cli, rc, true);
	}
	en_val = config->enable_inverted ? 0 : config->enable_val;
	rc = regulator_modify_register(dev, config->enable_reg,
			config->enable_mask, en_val);
	if (rc != 0) {
		return onoff_sync_finalize(&data->srv, key, NULL, rc, false);
	}
	return onoff_sync_finalize(&data->srv, key, cli, rc, true);
}

static int regulator_pmic_disable(const struct device *dev)
{
	struct regulator_data *data = dev->data;
	const struct regulator_config *config = dev->config;
	k_spinlock_key_t key;
	uint8_t dis_val;
	int rc;

	LOG_DBG("Disabling regulator");
	rc = onoff_sync_lock(&data->srv, &key);
	if (rc == 0) {
		rc = -EINVAL;
		return onoff_sync_finalize(&data->srv, key, NULL, rc, false);
	} else if (rc == 1) {
		/* Disable regulator */
		dis_val = config->enable_inverted ? config->enable_val : 0;
		rc = regulator_modify_register(dev, config->enable_reg,
				config->enable_mask, dis_val);
	}
	return onoff_sync_finalize(&data->srv, key, NULL, rc, false);
}

static int pmic_reg_init(const struct device *dev)
{
	const struct regulator_config *config = dev->config;
	struct regulator_data *data = dev->data;
	int rc  = 0;

	/* Cast the voltage array set at compile time to the voltage range
	 * struct
	 */
	data->voltages = (struct voltage_range *)config->voltage_array;
	/* Do the same cast for current limit ranges */
	data->current_levels = (struct current_range *)config->current_array;
	/* Check to verify we have a valid I2C device */
	if (!device_is_ready(config->i2c.bus)) {
		return -ENODEV;
	}
	if (config->boot_on) {
		rc = regulator_pmic_enable(dev, NULL);
	}
	if (config->initial_mode) {
		rc = regulator_pmic_set_mode(dev, config->initial_mode);
	}
	return rc;
}


static const struct regulator_driver_api api = {
	.enable = regulator_pmic_enable,
	.disable = regulator_pmic_disable,
	.count_voltages = regulator_pmic_count_voltages,
	.count_modes = regulator_pmic_count_modes,
	.list_voltages = regulator_pmic_list_voltages,
	.is_supported_voltage = regulator_pmic_is_supported_voltage,
	.set_voltage = regulator_pmic_set_voltage,
	.get_voltage = regulator_pmic_get_voltage,
	.set_current_limit = regulator_pmic_set_current_limit,
	.get_current_limit = regulator_pmic_get_current_limit,
	.set_mode = regulator_pmic_set_mode,
	.set_mode_voltage = regulator_pmic_set_mode_voltage,
	.get_mode_voltage = regulator_pmic_get_mode_voltage,
	.mode_disable = regulator_pmic_mode_disable,
	.mode_enable = regulator_pmic_mode_enable,
};

/*
 * Each regulator output will be initialized as a separate device struct,
 * and implement the regulator API. Since the DT binding is defined for the
 * entire regulator, this macro will be called for each child node of the
 * regulator device. This allows the regulator to have common DTS properties
 * shared between each regulator output
 */
#define CONFIGURE_REGULATOR_OUTPUT(node, ord)							\
	static uint32_t pmic_reg_##ord##_cur_limits[] =						\
		DT_PROP_OR(node, current_levels, {});						\
	static uint32_t pmic_reg_##ord##_vol_range[] =						\
		DT_PROP(node, voltage_range);							\
	static uint16_t pmic_reg_##ord##_allowed_modes[] =					\
		DT_PROP_OR(DT_PARENT(node), regulator_allowed_modes, {});			\
	static struct regulator_data pmic_reg_##ord##_data;					\
	static struct regulator_config pmic_reg_##ord##_cfg = {					\
		.vsel_mask = DT_PROP(node, vsel_mask),						\
		.vsel_reg = DT_PROP(node, vsel_reg),						\
		.num_voltages = DT_PROP(node, num_voltages),					\
		.num_current_levels = DT_PROP(node, num_current_levels),			\
		.enable_reg = DT_PROP(node, enable_reg),					\
		.enable_mask = DT_PROP(node, enable_mask),					\
		.enable_val = DT_PROP(node, enable_val),					\
		.min_uV = DT_PROP(node, min_uv),						\
		.max_uV = DT_PROP(node, max_uv),						\
		.ilim_reg = DT_PROP_OR(node, ilim_reg, 0),					\
		.ilim_mask = DT_PROP_OR(node, ilim_mask, 0),					\
		.enable_inverted = DT_PROP(node, enable_inverted),				\
		.boot_on = DT_PROP_OR(node, regulator_boot_on, false),				\
		.num_modes = ARRAY_SIZE(pmic_reg_##ord##_allowed_modes),			\
		.initial_mode = DT_PROP_OR(DT_PARENT(node), regulator_initial_mode, 0),		\
		.i2c = I2C_DT_SPEC_GET(DT_PARENT(node)),					\
		.voltage_array = pmic_reg_##ord##_vol_range,					\
		.current_array = pmic_reg_##ord##_cur_limits,					\
		.allowed_modes = pmic_reg_##ord##_allowed_modes,				\
		.modesel_offset = DT_PROP_OR(DT_PARENT(node), modesel_offset, 0),		\
		.modesel_reg = DT_PROP_OR(DT_PARENT(node), modesel_reg, 0),			\
		.modesel_mask = DT_PROP_OR(DT_PARENT(node), modesel_mask, 0),			\
	};											\
	DEVICE_DT_DEFINE(node, pmic_reg_init, NULL,						\
			      &pmic_reg_##ord##_data,						\
			      &pmic_reg_##ord##_cfg,						\
			      POST_KERNEL, CONFIG_PMIC_REGULATOR_INIT_PRIORITY,			\
			      &api);								\
/* Intermediate macros to extract DT node ordinal
 * (used as  a unique token for variable names)
 */
#define _CONFIGURE_REGULATOR_OUTPUT(node, ord)							\
	CONFIGURE_REGULATOR_OUTPUT(node, ord)

#define __CONFIGURE_REGULATOR_OUTPUT(node)							\
	_CONFIGURE_REGULATOR_OUTPUT(node, DT_DEP_ORD(node))

#define CONFIGURE_REGULATOR(id)									\
	DT_INST_FOREACH_CHILD(id, __CONFIGURE_REGULATOR_OUTPUT)

DT_INST_FOREACH_STATUS_OKAY(CONFIGURE_REGULATOR)