// SPDX-License-Identifier: GPL-2.0+
/*
 * tpl0102.c - Support for Texas Instruments digital potentiometers
 *
 * Copyright (C) 2016, 2018
 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
 *
 * TODO: enable/disable hi-z output control
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/iio/iio.h>

struct tpl0102_cfg {
        int wipers;
        int avail[3];
        int kohms;
};

enum tpl0102_type {
        CAT5140_503,
        CAT5140_104,
        TPL0102_104,
        TPL0401_103,
};

static const struct tpl0102_cfg tpl0102_cfg[] = {
        /* on-semiconductor parts */
        [CAT5140_503] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 50, },
        [CAT5140_104] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 100, },
        /* ti parts */
        [TPL0102_104] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 100 },
        [TPL0401_103] = { .wipers = 1, .avail = { 0, 1, 127 }, .kohms = 10, },
};

struct tpl0102_data {
        struct regmap *regmap;
        const struct tpl0102_cfg *cfg;
};

static const struct regmap_config tpl0102_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
};

#define TPL0102_CHANNEL(ch) {                                   \
        .type = IIO_RESISTANCE,                                 \
        .indexed = 1,                                           \
        .output = 1,                                            \
        .channel = (ch),                                        \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
        .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), \
}

static const struct iio_chan_spec tpl0102_channels[] = {
        TPL0102_CHANNEL(0),
        TPL0102_CHANNEL(1),
};

static int tpl0102_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct tpl0102_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW: {
                int ret = regmap_read(data->regmap, chan->channel, val);

                return ret ? ret : IIO_VAL_INT;
        }
        case IIO_CHAN_INFO_SCALE:
                *val = 1000 * data->cfg->kohms;
                *val2 = data->cfg->avail[2] + 1;
                return IIO_VAL_FRACTIONAL;
        }

        return -EINVAL;
}

static int tpl0102_read_avail(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              const int **vals, int *type, int *length,
                              long mask)
{
        struct tpl0102_data *data = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                *length = ARRAY_SIZE(data->cfg->avail);
                *vals = data->cfg->avail;
                *type = IIO_VAL_INT;
                return IIO_AVAIL_RANGE;
        }

        return -EINVAL;
}

static int tpl0102_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct tpl0102_data *data = iio_priv(indio_dev);

        if (mask != IIO_CHAN_INFO_RAW)
                return -EINVAL;

        if (val > data->cfg->avail[2] || val < 0)
                return -EINVAL;

        return regmap_write(data->regmap, chan->channel, val);
}

static const struct iio_info tpl0102_info = {
        .read_raw = tpl0102_read_raw,
        .read_avail = tpl0102_read_avail,
        .write_raw = tpl0102_write_raw,
};

static int tpl0102_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct device *dev = &client->dev;
        struct tpl0102_data *data;
        struct iio_dev *indio_dev;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
        if (!indio_dev)
                return -ENOMEM;
        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);

        data->cfg = &tpl0102_cfg[id->driver_data];
        data->regmap = devm_regmap_init_i2c(client, &tpl0102_regmap_config);
        if (IS_ERR(data->regmap)) {
                dev_err(dev, "regmap initialization failed\n");
                return PTR_ERR(data->regmap);
        }

        indio_dev->info = &tpl0102_info;
        indio_dev->channels = tpl0102_channels;
        indio_dev->num_channels = data->cfg->wipers;
        indio_dev->name = client->name;

        return devm_iio_device_register(dev, indio_dev);
}

static const struct i2c_device_id tpl0102_id[] = {
        { "cat5140-503", CAT5140_503 },
        { "cat5140-104", CAT5140_104 },
        { "tpl0102-104", TPL0102_104 },
        { "tpl0401-103", TPL0401_103 },
        { }
};
MODULE_DEVICE_TABLE(i2c, tpl0102_id);

static struct i2c_driver tpl0102_driver = {
        .driver = {
                .name = "tpl0102",
        },
        .probe = tpl0102_probe,
        .id_table = tpl0102_id,
};

module_i2c_driver(tpl0102_driver);

MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
MODULE_DESCRIPTION("TPL0102 digital potentiometer");
MODULE_LICENSE("GPL");