// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2022 Analog Devices, Inc.
 * ADI MAX77541 ADC Driver with IIO interface
 */

#include <linux/bitfield.h>
#include <linux/iio/iio.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/units.h>

#include <linux/mfd/max77541.h>

enum max77541_adc_range {
        LOW_RANGE,
        MID_RANGE,
        HIGH_RANGE,
};

enum max77541_adc_channel {
        MAX77541_ADC_VSYS_V,
        MAX77541_ADC_VOUT1_V,
        MAX77541_ADC_VOUT2_V,
        MAX77541_ADC_TEMP,
};

static int max77541_adc_offset(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int *val, int *val2)
{
        switch (chan->channel) {
        case MAX77541_ADC_TEMP:
                *val = DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS, 1725);
                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static int max77541_adc_scale(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int *val, int *val2)
{
        struct regmap **regmap = iio_priv(indio_dev);
        unsigned int reg_val;
        int ret;

        switch (chan->channel) {
        case MAX77541_ADC_VSYS_V:
                *val = 25;
                return IIO_VAL_INT;
        case MAX77541_ADC_VOUT1_V:
        case MAX77541_ADC_VOUT2_V:
                ret = regmap_read(*regmap, MAX77541_REG_M2_CFG1, &reg_val);
                if (ret)
                        return ret;

                reg_val = FIELD_GET(MAX77541_BITS_MX_CFG1_RNG, reg_val);
                switch (reg_val) {
                case LOW_RANGE:
                        *val = 6;
                        *val2 = 250000;
                        break;
                case MID_RANGE:
                        *val = 12;
                        *val2 = 500000;
                        break;
                case HIGH_RANGE:
                        *val = 25;
                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }

                return IIO_VAL_INT_PLUS_MICRO;
        case MAX77541_ADC_TEMP:
                *val = 1725;
                return IIO_VAL_INT;
        default:
                return -EINVAL;
        }
}

static int max77541_adc_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val)
{
        struct regmap **regmap = iio_priv(indio_dev);
        int ret;

        ret = regmap_read(*regmap, chan->address, val);
        if (ret)
                return ret;

        return IIO_VAL_INT;
}

#define MAX77541_ADC_CHANNEL_V(_channel, _name, _type, _reg) \
        {                                                       \
                .type = _type,                                  \
                .indexed = 1,                                   \
                .channel = _channel,                            \
                .address = _reg,                                \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                                      BIT(IIO_CHAN_INFO_SCALE), \
                .datasheet_name = _name,                        \
        }

#define MAX77541_ADC_CHANNEL_TEMP(_channel, _name, _type, _reg) \
        {                                                       \
                .type = _type,                                  \
                .indexed = 1,                                   \
                .channel = _channel,                            \
                .address = _reg,                                \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                                      BIT(IIO_CHAN_INFO_SCALE) |\
                                      BIT(IIO_CHAN_INFO_OFFSET),\
                .datasheet_name = _name,                        \
        }

static const struct iio_chan_spec max77541_adc_channels[] = {
        MAX77541_ADC_CHANNEL_V(MAX77541_ADC_VSYS_V, "vsys_v", IIO_VOLTAGE,
                               MAX77541_REG_ADC_DATA_CH1),
        MAX77541_ADC_CHANNEL_V(MAX77541_ADC_VOUT1_V, "vout1_v", IIO_VOLTAGE,
                               MAX77541_REG_ADC_DATA_CH2),
        MAX77541_ADC_CHANNEL_V(MAX77541_ADC_VOUT2_V, "vout2_v", IIO_VOLTAGE,
                               MAX77541_REG_ADC_DATA_CH3),
        MAX77541_ADC_CHANNEL_TEMP(MAX77541_ADC_TEMP, "temp", IIO_TEMP,
                                  MAX77541_REG_ADC_DATA_CH6),
};

static int max77541_adc_read_raw(struct iio_dev *indio_dev,
                                 struct iio_chan_spec const *chan,
                                 int *val, int *val2, long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_OFFSET:
                return max77541_adc_offset(indio_dev, chan, val, val2);
        case IIO_CHAN_INFO_SCALE:
                return max77541_adc_scale(indio_dev, chan, val, val2);
        case IIO_CHAN_INFO_RAW:
                return max77541_adc_raw(indio_dev, chan, val);
        default:
                return -EINVAL;
        }
}

static const struct iio_info max77541_adc_info = {
        .read_raw = max77541_adc_read_raw,
};

static int max77541_adc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iio_dev *indio_dev;
        struct regmap **regmap;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*regmap));
        if (!indio_dev)
                return -ENOMEM;

        regmap = iio_priv(indio_dev);

        *regmap = dev_get_regmap(dev->parent, NULL);
        indio_dev->modes = INDIO_DIRECT_MODE;

        indio_dev->name = "max77541";
        indio_dev->info = &max77541_adc_info;
        indio_dev->channels = max77541_adc_channels;
        indio_dev->num_channels = ARRAY_SIZE(max77541_adc_channels);

        return devm_iio_device_register(dev, indio_dev);
}

static const struct platform_device_id max77541_adc_platform_id[] = {
        { "max77541-adc" },
        { }
};
MODULE_DEVICE_TABLE(platform, max77541_adc_platform_id);

static struct platform_driver max77541_adc_driver = {
        .driver = {
                .name = "max77541-adc",
        },
        .probe = max77541_adc_probe,
        .id_table = max77541_adc_platform_id,
};
module_platform_driver(max77541_adc_driver);

MODULE_AUTHOR("Okan Sahin <Okan.Sahin@analog.com>");
MODULE_DESCRIPTION("MAX77541 ADC driver");
MODULE_LICENSE("GPL");