/*
 * Copyright 2021 Grinn
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT ti_ina237

#include "ina237.h"
#include "ina23x_common.h"

#include <zephyr/logging/log.h>
#include <zephyr/drivers/sensor.h>
#include <zephyr/dt-bindings/sensor/ina237.h>
#include <zephyr/sys/byteorder.h>

LOG_MODULE_REGISTER(INA237, CONFIG_SENSOR_LOG_LEVEL);

/** @brief Calibration scaling value (scaled by 10^-5) */
#define INA237_CAL_SCALING 8192ULL

/** @brief The LSB value for the bus voltage register, in microvolts/LSB. */
#define INA237_BUS_VOLTAGE_TO_uV(x) ((x) * 3125U)

/** @brief Power scaling (need factor of 0.2) */
#define INA237_POWER_TO_uW(x) ((x) / 5ULL)

/**
 * @brief Scale die temperture from 0.125 degC/bit to micro-degrees C
 *  Note that the bottom 4 bits are reserved and are always zero.
 */
#define INA237_DIETEMP_TO_uDegC(x) (((x) >> 4) * 125000)

static void micro_s32_to_sensor_value(struct sensor_value *val, int32_t value_microX)
{
	val->val1 = value_microX / 1000000L;
	val->val2 = value_microX % 1000000L;
}

static void micro_u64_to_sensor_value(struct sensor_value *val, uint64_t value_microX)
{
	val->val1 = value_microX / 1000000U;
	val->val2 = value_microX % 1000000U;
}

static int ina237_channel_get(const struct device *dev, enum sensor_channel chan,
			      struct sensor_value *val)
{
	const struct ina237_data *data = dev->data;
	const struct ina237_config *config = dev->config;

	switch (chan) {
	case SENSOR_CHAN_VOLTAGE:
		micro_s32_to_sensor_value(val, INA237_BUS_VOLTAGE_TO_uV(data->bus_voltage));
		break;

	case SENSOR_CHAN_CURRENT:
		/* see datasheet "Current and Power calculations" section */
		micro_s32_to_sensor_value(val, data->current * config->current_lsb);
		break;

	case SENSOR_CHAN_POWER:
		/* power in uW is power_reg * current_lsb * 0.2 */
		micro_u64_to_sensor_value(val,
			INA237_POWER_TO_uW((uint64_t)data->power * config->current_lsb));
		break;

#ifdef CONFIG_INA237_VSHUNT
	case SENSOR_CHAN_VSHUNT:
		if (config->config & INA237_CFG_HIGH_PRECISION) {
			/* high-resolution mode - 1.25 uV/bit, sensor value is in mV */
			micro_s32_to_sensor_value(val, data->shunt_voltage * 1250);
		} else {
			/* standard-resolution - 5 uV/bit -> nano-volts */
			micro_s32_to_sensor_value(val, data->shunt_voltage * 5000);
		}
		break;
#endif /* CONFIG_INA237_VSHUNT */

	case SENSOR_CHAN_DIE_TEMP:
		micro_s32_to_sensor_value(val, INA237_DIETEMP_TO_uDegC(data->die_temp));
		break;

	default:
		return -ENOTSUP;
	}

	return 0;
}

/**
 * @brief sensor operation mode check
 *
 * @retval true if set or false if not set
 */
static bool ina237_is_triggered_mode_set(const struct device *dev)
{
	const struct ina237_config *config = dev->config;

	uint8_t mode = (config->adc_config & GENMASK(15, 12)) >> 12;

	switch (mode) {
	case INA237_OPER_MODE_BUS_VOLTAGE_TRIG:
	case INA237_OPER_MODE_SHUNT_VOLTAGE_TRIG:
	case INA237_OPER_MODE_SHUNT_BUS_VOLTAGE_TRIG:
	case INA237_OPER_MODE_TEMP_TRIG:
	case INA237_OPER_MODE_TEMP_BUS_VOLTAGE_TRIG:
	case INA237_OPER_MODE_TEMP_SHUNT_VOLTAGE_TRIG:
	case INA237_OPER_MODE_BUS_SHUNT_VOLTAGE_TEMP_TRIG:
		return true;
	default:
		return false;
	}
}

/**
 * @brief request for one shot measurement
 *
 * @retval 0 for success
 * @retval negative errno code on fail
 */
static int ina237_trigg_one_shot_request(const struct device *dev)
{
	const struct ina237_config *config = dev->config;
	int ret;

	ret = ina23x_reg_write(&config->bus, INA237_REG_ADC_CONFIG, config->adc_config);
	if (ret < 0) {
		LOG_ERR("Failed to write ADC configuration register!");
		return ret;
	}

	return 0;
}

/**
 * @brief sensor data read
 *
 * @retval 0 for success
 * @retval -EIO in case of input / output error
 */
static int ina237_read_data(const struct device *dev)
{
	struct ina237_data *data = dev->data;
	const struct ina237_config *config = dev->config;
	int ret;

	if ((data->chan == SENSOR_CHAN_ALL) || (data->chan == SENSOR_CHAN_VOLTAGE)) {
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_BUS_VOLT, &data->bus_voltage);
		if (ret < 0) {
			LOG_ERR("Failed to read bus voltage");
			return ret;
		}
	}

	if ((data->chan == SENSOR_CHAN_ALL) || (data->chan == SENSOR_CHAN_CURRENT)) {
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_CURRENT, &data->current);
		if (ret < 0) {
			LOG_ERR("Failed to read current");
			return ret;
		}
	}

	if ((data->chan == SENSOR_CHAN_ALL) || (data->chan == SENSOR_CHAN_POWER)) {
		ret = ina23x_reg_read_24(&config->bus, INA237_REG_POWER, &data->power);
		if (ret < 0) {
			LOG_ERR("Failed to read power");
			return ret;
		}
	}

	if ((data->chan == SENSOR_CHAN_ALL) || (data->chan == SENSOR_CHAN_DIE_TEMP)) {
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_DIETEMP, &data->die_temp);
		if (ret < 0) {
			LOG_ERR("Failed to read temperature");
			return ret;
		}
	}

#ifdef CONFIG_INA237_VSHUNT
	if ((data->chan == SENSOR_CHAN_ALL) || (data->chan == SENSOR_CHAN_VSHUNT)) {
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_SHUNT_VOLT, &data->shunt_voltage);
		if (ret < 0) {
			LOG_ERR("Failed to read shunt voltage");
			return ret;
		}
	}
#endif /* CONFIG_INA237_VSHUNT */

	return 0;
}

/**
 * @brief sensor sample fetch
 *
 * @retval 0 for success
 * @retval negative errno code on fail
 */
static int ina237_sample_fetch(const struct device *dev, enum sensor_channel chan)
{
	struct ina237_data *data = dev->data;

	if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_VOLTAGE && chan != SENSOR_CHAN_CURRENT &&
		chan != SENSOR_CHAN_POWER &&
#ifdef CONFIG_INA237_VSHUNT
		chan != SENSOR_CHAN_VSHUNT &&
#endif /* CONFIG_INA237_VSHUNT */
		chan != SENSOR_CHAN_DIE_TEMP) {
		return -ENOTSUP;
	}

	data->chan = chan;

	if (ina237_is_triggered_mode_set(dev)) {
		return ina237_trigg_one_shot_request(dev);
	} else {
		return ina237_read_data(dev);
	}
}

static int ina237_attr_set(const struct device *dev, enum sensor_channel chan,
			   enum sensor_attribute attr, const struct sensor_value *val)
{
	const struct ina237_config *config = dev->config;
	uint16_t data = val->val1;

	switch (attr) {
	case SENSOR_ATTR_CONFIGURATION:
		return ina23x_reg_write(&config->bus, INA237_REG_CONFIG, data);
	case SENSOR_ATTR_CALIBRATION:
		return ina23x_reg_write(&config->bus, INA237_REG_CALIB, data);
	default:
		LOG_ERR("INA237 attribute not supported.");
		return -ENOTSUP;
	}
}

static int ina237_attr_get(const struct device *dev, enum sensor_channel chan,
			   enum sensor_attribute attr, struct sensor_value *val)
{
	const struct ina237_config *config = dev->config;
	uint16_t data;
	int ret;

	switch (attr) {
	case SENSOR_ATTR_CONFIGURATION:
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_CONFIG, &data);
		if (ret < 0) {
			return ret;
		}
		break;
	case SENSOR_ATTR_CALIBRATION:
		ret = ina23x_reg_read_16(&config->bus, INA237_REG_CALIB, &data);
		if (ret < 0) {
			return ret;
		}
		break;
	default:
		LOG_ERR("INA237 attribute not supported.");
		return -ENOTSUP;
	}

	val->val1 = data;
	val->val2 = 0;

	return 0;
}

static int ina237_calibrate(const struct device *dev)
{
	const struct ina237_config *config = dev->config;
	int ret;

	/* see datasheet "Current and Power calculations" section */
	ret = ina23x_reg_write(&config->bus, INA237_REG_CALIB, config->cal);
	if (ret < 0) {
		return ret;
	}

	return 0;
}

static void ina237_trigger_work_handler(struct k_work *work)
{
	struct ina23x_trigger *trigg = CONTAINER_OF(work, struct ina23x_trigger, conversion_work);
	struct ina237_data *data = CONTAINER_OF(trigg, struct ina237_data, trigger);
	const struct ina237_config *config = data->dev->config;
	int ret;
	uint16_t reg_alert;

	/* Read reg alert to clear alerts */
	ret = ina23x_reg_read_16(&config->bus, INA237_REG_ALERT, &reg_alert);
	if (ret < 0) {
		LOG_ERR("Failed to read alert register!");
		return;
	}

	ret = ina237_read_data(data->dev);
	if (ret < 0) {
		LOG_WRN("Unable to read data, ret %d", ret);
	}

	if (data->trigger.handler_alert) {
		data->trigger.handler_alert(data->dev, data->trigger.trig_alert);
	}
}

static int ina237_init(const struct device *dev)
{
	struct ina237_data *data = dev->data;
	const struct ina237_config *config = dev->config;
	uint16_t id;
	int ret;

	if (!device_is_ready(config->bus.bus)) {
		LOG_ERR("I2C bus %s is not ready", config->bus.bus->name);
		return -ENODEV;
	}

	data->dev = dev;

	ret = ina23x_reg_read_16(&config->bus, INA237_REG_MANUFACTURER_ID, &id);
	if (ret < 0) {
		LOG_ERR("Failed to read manufacturer register!");
		return ret;
	}

	if (id != INA237_MANUFACTURER_ID) {
		LOG_ERR("Manufacturer ID doesn't match!");
		return -ENODEV;
	}

	ret = ina23x_reg_write(&config->bus, INA237_REG_ADC_CONFIG, config->adc_config);
	if (ret < 0) {
		LOG_ERR("Failed to write ADC configuration register!");
		return ret;
	}

	ret = ina23x_reg_write(&config->bus, INA237_REG_CONFIG, config->config);
	if (ret < 0) {
		LOG_ERR("Failed to write configuration register!");
		return ret;
	}

	ret = ina237_calibrate(dev);
	if (ret < 0) {
		LOG_ERR("Failed to write calibration register!");
		return ret;
	}

	if (ina237_is_triggered_mode_set(dev)) {
		if ((config->alert_config & GENMASK(15, 14)) != GENMASK(15, 14)) {
			LOG_ERR("ALATCH and CNVR bits must be enabled in triggered mode!");
			return -ENODEV;
		}

		k_work_init(&data->trigger.conversion_work, ina237_trigger_work_handler);

		ret = ina23x_trigger_mode_init(&data->trigger, &config->alert_gpio);
		if (ret < 0) {
			LOG_ERR("Failed to init trigger mode");
			return ret;
		}

		ret = ina23x_reg_write(&config->bus, INA237_REG_ALERT, config->alert_config);
		if (ret < 0) {
			LOG_ERR("Failed to write alert configuration register!");
			return ret;
		}
	}

	return 0;
}

static int ina237_trigger_set(const struct device *dev, const struct sensor_trigger *trig,
			      sensor_trigger_handler_t handler)
{
	ARG_UNUSED(trig);
	struct ina237_data *ina237 = dev->data;

	if (!ina237_is_triggered_mode_set(dev)) {
		return -ENOTSUP;
	}

	ina237->trigger.handler_alert = handler;
	ina237->trigger.trig_alert = trig;

	return 0;
}

static const struct sensor_driver_api ina237_driver_api = {
	.attr_set = ina237_attr_set,
	.attr_get = ina237_attr_get,
	.trigger_set = ina237_trigger_set,
	.sample_fetch = ina237_sample_fetch,
	.channel_get = ina237_channel_get,
};

/* Shunt calibration must be muliplied by 4 if high-prevision mode is selected */
#define CAL_PRECISION_MULTIPLIER(config) \
	(((config & INA237_CFG_HIGH_PRECISION) >> 4) * 3 + 1)

#define INA237_DRIVER_INIT(inst)                                                                   \
	static struct ina237_data ina237_data_##inst;                                              \
	static const struct ina237_config ina237_config_##inst = {                                 \
		.bus = I2C_DT_SPEC_INST_GET(inst),                                                 \
		.config = DT_INST_PROP(inst, config),                                              \
		.adc_config = DT_INST_PROP(inst, adc_config) |                                     \
			(DT_INST_ENUM_IDX(inst, adc_mode) << 12) |                             \
			(DT_INST_ENUM_IDX(inst, vbus_conversion_time_us) << 9) |                 \
			(DT_INST_ENUM_IDX(inst, vshunt_conversion_time_us) << 6) |               \
			(DT_INST_ENUM_IDX(inst, temp_conversion_time_us) << 3) |                 \
			DT_INST_ENUM_IDX(inst, avg_count),                                        \
		.current_lsb = DT_INST_PROP(inst, current_lsb_microamps),                          \
		.cal = CAL_PRECISION_MULTIPLIER(DT_INST_PROP(inst, config)) *                      \
			INA237_CAL_SCALING * DT_INST_PROP(inst, current_lsb_microamps) *       \
			DT_INST_PROP(inst, rshunt_micro_ohms) / 10000000ULL,                   \
		.alert_config = DT_INST_PROP_OR(inst, alert_config, 0x01),                         \
		.alert_gpio = GPIO_DT_SPEC_INST_GET_OR(inst, alert_gpios, {0}),                    \
	};                                                                                         \
	SENSOR_DEVICE_DT_INST_DEFINE(inst, &ina237_init, NULL, &ina237_data_##inst,                \
				     &ina237_config_##inst, POST_KERNEL,                           \
				     CONFIG_SENSOR_INIT_PRIORITY, &ina237_driver_api);             \

DT_INST_FOREACH_STATUS_OKAY(INA237_DRIVER_INIT)