// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * MP2629 Driver for ADC
 *
 * Copyright 2020 Monolithic Power Systems, Inc
 *
 * Author: Saravanan Sekar <sravanhome@gmail.com>
 */

#include <linux/iio/driver.h>
#include <linux/iio/iio.h>
#include <linux/iio/machine.h>
#include <linux/mfd/mp2629.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define MP2629_REG_ADC_CTRL             0x03
#define MP2629_REG_BATT_VOLT            0x0e
#define MP2629_REG_SYSTEM_VOLT          0x0f
#define MP2629_REG_INPUT_VOLT           0x11
#define MP2629_REG_BATT_CURRENT         0x12
#define MP2629_REG_INPUT_CURRENT        0x13

#define MP2629_ADC_START                BIT(7)
#define MP2629_ADC_CONTINUOUS           BIT(6)

#define MP2629_MAP(_mp, _mpc) IIO_MAP(#_mp, "mp2629_charger", "mp2629-"_mpc)

#define MP2629_ADC_CHAN(_ch, _type) {                           \
        .type = _type,                                          \
        .indexed = 1,                                           \
        .datasheet_name = #_ch,                                 \
        .channel = MP2629_ ## _ch,                              \
        .address = MP2629_REG_ ## _ch,                          \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
}

struct mp2629_adc {
        struct regmap *regmap;
        struct device *dev;
};

static const struct iio_chan_spec mp2629_channels[] = {
        MP2629_ADC_CHAN(BATT_VOLT, IIO_VOLTAGE),
        MP2629_ADC_CHAN(SYSTEM_VOLT, IIO_VOLTAGE),
        MP2629_ADC_CHAN(INPUT_VOLT, IIO_VOLTAGE),
        MP2629_ADC_CHAN(BATT_CURRENT, IIO_CURRENT),
        MP2629_ADC_CHAN(INPUT_CURRENT, IIO_CURRENT)
};

static const struct iio_map mp2629_adc_maps[] = {
        MP2629_MAP(BATT_VOLT, "batt-volt"),
        MP2629_MAP(SYSTEM_VOLT, "system-volt"),
        MP2629_MAP(INPUT_VOLT, "input-volt"),
        MP2629_MAP(BATT_CURRENT, "batt-current"),
        MP2629_MAP(INPUT_CURRENT, "input-current"),
        { }
};

static int mp2629_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val, int *val2, long mask)
{
        struct mp2629_adc *info = iio_priv(indio_dev);
        unsigned int rval;
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = regmap_read(info->regmap, chan->address, &rval);
                if (ret)
                        return ret;

                if (chan->channel == MP2629_INPUT_VOLT)
                        rval &= GENMASK(6, 0);
                *val = rval;
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                switch (chan->channel) {
                case MP2629_BATT_VOLT:
                case MP2629_SYSTEM_VOLT:
                        *val = 20;
                        return IIO_VAL_INT;

                case MP2629_INPUT_VOLT:
                        *val = 60;
                        return IIO_VAL_INT;

                case MP2629_BATT_CURRENT:
                        *val = 175;
                        *val2 = 10;
                        return IIO_VAL_FRACTIONAL;

                case MP2629_INPUT_CURRENT:
                        *val = 133;
                        *val2 = 10;
                        return IIO_VAL_FRACTIONAL;

                default:
                        return -EINVAL;
                }

        default:
                return -EINVAL;
        }
}

static const struct iio_info mp2629_adc_info = {
        .read_raw = &mp2629_read_raw,
};

static int mp2629_adc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct mp2629_data *ddata = dev_get_drvdata(dev->parent);
        struct mp2629_adc *info;
        struct iio_dev *indio_dev;
        int ret;

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

        info = iio_priv(indio_dev);
        info->regmap = ddata->regmap;
        info->dev = dev;
        platform_set_drvdata(pdev, indio_dev);

        ret = regmap_set_bits(info->regmap, MP2629_REG_ADC_CTRL,
                              MP2629_ADC_START | MP2629_ADC_CONTINUOUS);
        if (ret) {
                dev_err(dev, "adc enable fail: %d\n", ret);
                return ret;
        }

        ret = iio_map_array_register(indio_dev, mp2629_adc_maps);
        if (ret) {
                dev_err(dev, "IIO maps register fail: %d\n", ret);
                goto fail_disable;
        }

        indio_dev->name = "mp2629-adc";
        indio_dev->channels = mp2629_channels;
        indio_dev->num_channels = ARRAY_SIZE(mp2629_channels);
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &mp2629_adc_info;

        ret = iio_device_register(indio_dev);
        if (ret) {
                dev_err(dev, "IIO device register fail: %d\n", ret);
                goto fail_map_unregister;
        }

        return 0;

fail_map_unregister:
        iio_map_array_unregister(indio_dev);

fail_disable:
        regmap_clear_bits(info->regmap, MP2629_REG_ADC_CTRL,
                          MP2629_ADC_CONTINUOUS);
        regmap_clear_bits(info->regmap, MP2629_REG_ADC_CTRL, MP2629_ADC_START);

        return ret;
}

static void mp2629_adc_remove(struct platform_device *pdev)
{
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct mp2629_adc *info = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        iio_map_array_unregister(indio_dev);

        regmap_clear_bits(info->regmap, MP2629_REG_ADC_CTRL,
                          MP2629_ADC_CONTINUOUS);
        regmap_clear_bits(info->regmap, MP2629_REG_ADC_CTRL, MP2629_ADC_START);
}

static const struct of_device_id mp2629_adc_of_match[] = {
        { .compatible = "mps,mp2629_adc" },
        { }
};
MODULE_DEVICE_TABLE(of, mp2629_adc_of_match);

static struct platform_driver mp2629_adc_driver = {
        .driver = {
                .name = "mp2629_adc",
                .of_match_table = mp2629_adc_of_match,
        },
        .probe          = mp2629_adc_probe,
        .remove         = mp2629_adc_remove,
};
module_platform_driver(mp2629_adc_driver);

MODULE_AUTHOR("Saravanan Sekar <sravanhome@gmail.com>");
MODULE_DESCRIPTION("MP2629 ADC driver");
MODULE_LICENSE("GPL");