// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI LP8788 MFD - ADC driver
 *
 * Copyright 2012 Texas Instruments
 *
 * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
 */

#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/machine.h>
#include <linux/mfd/lp8788.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

/* register address */
#define LP8788_ADC_CONF                 0x60
#define LP8788_ADC_RAW                  0x61
#define LP8788_ADC_DONE                 0x63

#define ADC_CONV_START                  1

struct lp8788_adc {
        struct lp8788 *lp;
        const struct iio_map *map;
        struct mutex lock;
};

static const int lp8788_scale[LPADC_MAX] = {
        [LPADC_VBATT_5P5] = 1343101,
        [LPADC_VIN_CHG]   = 3052503,
        [LPADC_IBATT]     = 610500,
        [LPADC_IC_TEMP]   = 61050,
        [LPADC_VBATT_6P0] = 1465201,
        [LPADC_VBATT_5P0] = 1221001,
        [LPADC_ADC1]      = 610500,
        [LPADC_ADC2]      = 610500,
        [LPADC_VDD]       = 1025641,
        [LPADC_VCOIN]     = 757020,
        [LPADC_ADC3]      = 610500,
        [LPADC_ADC4]      = 610500,
};

static int lp8788_get_adc_result(struct lp8788_adc *adc, enum lp8788_adc_id id,
                                int *val)
{
        unsigned int msb;
        unsigned int lsb;
        unsigned int result;
        u8 data;
        u8 rawdata[2];
        int size = ARRAY_SIZE(rawdata);
        int retry = 5;
        int ret;

        data = (id << 1) | ADC_CONV_START;
        ret = lp8788_write_byte(adc->lp, LP8788_ADC_CONF, data);
        if (ret)
                goto err_io;

        /* retry until adc conversion is done */
        data = 0;
        while (retry--) {
                usleep_range(100, 200);

                ret = lp8788_read_byte(adc->lp, LP8788_ADC_DONE, &data);
                if (ret)
                        goto err_io;

                /* conversion done */
                if (data)
                        break;
        }

        ret = lp8788_read_multi_bytes(adc->lp, LP8788_ADC_RAW, rawdata, size);
        if (ret)
                goto err_io;

        msb = (rawdata[0] << 4) & 0x00000ff0;
        lsb = (rawdata[1] >> 4) & 0x0000000f;
        result = msb | lsb;
        *val = result;

        return 0;

err_io:
        return ret;
}

static int lp8788_adc_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val, int *val2, long mask)
{
        struct lp8788_adc *adc = iio_priv(indio_dev);
        enum lp8788_adc_id id = chan->channel;
        int ret;

        mutex_lock(&adc->lock);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = lp8788_get_adc_result(adc, id, val) ? -EIO : IIO_VAL_INT;
                break;
        case IIO_CHAN_INFO_SCALE:
                *val = lp8788_scale[id] / 1000000;
                *val2 = lp8788_scale[id] % 1000000;
                ret = IIO_VAL_INT_PLUS_MICRO;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        mutex_unlock(&adc->lock);

        return ret;
}

static const struct iio_info lp8788_adc_info = {
        .read_raw = &lp8788_adc_read_raw,
};

#define LP8788_CHAN(_id, _type) {                               \
                .type = _type,                                  \
                .indexed = 1,                                   \
                .channel = LPADC_##_id,                         \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                        BIT(IIO_CHAN_INFO_SCALE),               \
                .datasheet_name = #_id,                         \
}

static const struct iio_chan_spec lp8788_adc_channels[] = {
        [LPADC_VBATT_5P5] = LP8788_CHAN(VBATT_5P5, IIO_VOLTAGE),
        [LPADC_VIN_CHG]   = LP8788_CHAN(VIN_CHG, IIO_VOLTAGE),
        [LPADC_IBATT]     = LP8788_CHAN(IBATT, IIO_CURRENT),
        [LPADC_IC_TEMP]   = LP8788_CHAN(IC_TEMP, IIO_TEMP),
        [LPADC_VBATT_6P0] = LP8788_CHAN(VBATT_6P0, IIO_VOLTAGE),
        [LPADC_VBATT_5P0] = LP8788_CHAN(VBATT_5P0, IIO_VOLTAGE),
        [LPADC_ADC1]      = LP8788_CHAN(ADC1, IIO_VOLTAGE),
        [LPADC_ADC2]      = LP8788_CHAN(ADC2, IIO_VOLTAGE),
        [LPADC_VDD]       = LP8788_CHAN(VDD, IIO_VOLTAGE),
        [LPADC_VCOIN]     = LP8788_CHAN(VCOIN, IIO_VOLTAGE),
        [LPADC_ADC3]      = LP8788_CHAN(ADC3, IIO_VOLTAGE),
        [LPADC_ADC4]      = LP8788_CHAN(ADC4, IIO_VOLTAGE),
};

/* default maps used by iio consumer (lp8788-charger driver) */
static const struct iio_map lp8788_default_iio_maps[] = {
        IIO_MAP("VBATT_5P0", "lp8788-charger", "lp8788_vbatt_5p0"),
        IIO_MAP("ADC1", "lp8788-charger", "lp8788_adc1"),
        { }
};

static int lp8788_iio_map_register(struct device *dev,
                                struct iio_dev *indio_dev,
                                struct lp8788_platform_data *pdata,
                                struct lp8788_adc *adc)
{
        const struct iio_map *map;
        int ret;

        map = (!pdata || !pdata->adc_pdata) ?
                lp8788_default_iio_maps : pdata->adc_pdata;

        ret = devm_iio_map_array_register(dev, indio_dev, map);
        if (ret) {
                dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
                return ret;
        }

        adc->map = map;
        return 0;
}

static int lp8788_adc_probe(struct platform_device *pdev)
{
        struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
        struct iio_dev *indio_dev;
        struct lp8788_adc *adc;
        int ret;

        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
        if (!indio_dev)
                return -ENOMEM;

        adc = iio_priv(indio_dev);
        adc->lp = lp;

        ret = lp8788_iio_map_register(&pdev->dev, indio_dev, lp->pdata, adc);
        if (ret)
                return ret;

        mutex_init(&adc->lock);

        indio_dev->name = pdev->name;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &lp8788_adc_info;
        indio_dev->channels = lp8788_adc_channels;
        indio_dev->num_channels = ARRAY_SIZE(lp8788_adc_channels);

        return devm_iio_device_register(&pdev->dev, indio_dev);
}

static struct platform_driver lp8788_adc_driver = {
        .probe = lp8788_adc_probe,
        .driver = {
                .name = LP8788_DEV_ADC,
        },
};
module_platform_driver(lp8788_adc_driver);

MODULE_DESCRIPTION("Texas Instruments LP8788 ADC Driver");
MODULE_AUTHOR("Milo Kim");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lp8788-adc");