// SPDX-License-Identifier: GPL-2.0
/*
 * Industrial I/O driver for Microchip digital potentiometers
 * Copyright (c) 2015  Axentia Technologies AB
 * Author: Peter Rosin <peda@axentia.se>
 *
 * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf
 *
 * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
 * mcp4531      1       129             5, 10, 50, 100          010111x
 * mcp4532      1       129             5, 10, 50, 100          01011xx
 * mcp4541      1       129             5, 10, 50, 100          010111x
 * mcp4542      1       129             5, 10, 50, 100          01011xx
 * mcp4551      1       257             5, 10, 50, 100          010111x
 * mcp4552      1       257             5, 10, 50, 100          01011xx
 * mcp4561      1       257             5, 10, 50, 100          010111x
 * mcp4562      1       257             5, 10, 50, 100          01011xx
 * mcp4631      2       129             5, 10, 50, 100          0101xxx
 * mcp4632      2       129             5, 10, 50, 100          01011xx
 * mcp4641      2       129             5, 10, 50, 100          0101xxx
 * mcp4642      2       129             5, 10, 50, 100          01011xx
 * mcp4651      2       257             5, 10, 50, 100          0101xxx
 * mcp4652      2       257             5, 10, 50, 100          01011xx
 * mcp4661      2       257             5, 10, 50, 100          0101xxx
 * mcp4662      2       257             5, 10, 50, 100          01011xx
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/property.h>

#include <linux/iio/iio.h>

struct mcp4531_cfg {
        int wipers;
        int avail[3];
        int kohms;
};

enum mcp4531_type {
        MCP453x_502,
        MCP453x_103,
        MCP453x_503,
        MCP453x_104,
        MCP454x_502,
        MCP454x_103,
        MCP454x_503,
        MCP454x_104,
        MCP455x_502,
        MCP455x_103,
        MCP455x_503,
        MCP455x_104,
        MCP456x_502,
        MCP456x_103,
        MCP456x_503,
        MCP456x_104,
        MCP463x_502,
        MCP463x_103,
        MCP463x_503,
        MCP463x_104,
        MCP464x_502,
        MCP464x_103,
        MCP464x_503,
        MCP464x_104,
        MCP465x_502,
        MCP465x_103,
        MCP465x_503,
        MCP465x_104,
        MCP466x_502,
        MCP466x_103,
        MCP466x_503,
        MCP466x_104,
};

static const struct mcp4531_cfg mcp4531_cfg[] = {
        [MCP453x_502] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =   5, },
        [MCP453x_103] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  10, },
        [MCP453x_503] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  50, },
        [MCP453x_104] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms = 100, },
        [MCP454x_502] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =   5, },
        [MCP454x_103] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  10, },
        [MCP454x_503] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms =  50, },
        [MCP454x_104] = { .wipers = 1, .avail = { 0, 1, 128 }, .kohms = 100, },
        [MCP455x_502] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =   5, },
        [MCP455x_103] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  10, },
        [MCP455x_503] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  50, },
        [MCP455x_104] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms = 100, },
        [MCP456x_502] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =   5, },
        [MCP456x_103] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  10, },
        [MCP456x_503] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms =  50, },
        [MCP456x_104] = { .wipers = 1, .avail = { 0, 1, 256 }, .kohms = 100, },
        [MCP463x_502] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =   5, },
        [MCP463x_103] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  10, },
        [MCP463x_503] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  50, },
        [MCP463x_104] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms = 100, },
        [MCP464x_502] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =   5, },
        [MCP464x_103] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  10, },
        [MCP464x_503] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms =  50, },
        [MCP464x_104] = { .wipers = 2, .avail = { 0, 1, 128 }, .kohms = 100, },
        [MCP465x_502] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =   5, },
        [MCP465x_103] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  10, },
        [MCP465x_503] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  50, },
        [MCP465x_104] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms = 100, },
        [MCP466x_502] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =   5, },
        [MCP466x_103] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  10, },
        [MCP466x_503] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms =  50, },
        [MCP466x_104] = { .wipers = 2, .avail = { 0, 1, 256 }, .kohms = 100, },
};

#define MCP4531_WRITE (0 << 2)
#define MCP4531_INCR  (1 << 2)
#define MCP4531_DECR  (2 << 2)
#define MCP4531_READ  (3 << 2)

#define MCP4531_WIPER_SHIFT (4)

struct mcp4531_data {
        struct i2c_client *client;
        const struct mcp4531_cfg *cfg;
};

#define MCP4531_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_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW),   \
}

static const struct iio_chan_spec mcp4531_channels[] = {
        MCP4531_CHANNEL(0),
        MCP4531_CHANNEL(1),
};

static int mcp4531_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct mcp4531_data *data = iio_priv(indio_dev);
        int address = chan->channel << MCP4531_WIPER_SHIFT;
        s32 ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = i2c_smbus_read_word_swapped(data->client,
                                                  MCP4531_READ | address);
                if (ret < 0)
                        return ret;
                *val = ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = 1000 * data->cfg->kohms;
                *val2 = data->cfg->avail[2];
                return IIO_VAL_FRACTIONAL;
        }

        return -EINVAL;
}

static int mcp4531_read_avail(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              const int **vals, int *type, int *length,
                              long mask)
{
        struct mcp4531_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 mcp4531_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct mcp4531_data *data = iio_priv(indio_dev);
        int address = chan->channel << MCP4531_WIPER_SHIFT;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (val > data->cfg->avail[2] || val < 0)
                        return -EINVAL;
                break;
        default:
                return -EINVAL;
        }

        return i2c_smbus_write_byte_data(data->client,
                                         MCP4531_WRITE | address | (val >> 8),
                                         val & 0xff);
}

static const struct iio_info mcp4531_info = {
        .read_raw = mcp4531_read_raw,
        .read_avail = mcp4531_read_avail,
        .write_raw = mcp4531_write_raw,
};

#define MCP4531_ID_TABLE(_name, cfg) {                          \
        .name = _name,                                          \
        .driver_data = (kernel_ulong_t)&mcp4531_cfg[cfg],       \
}

static const struct i2c_device_id mcp4531_id[] = {
        MCP4531_ID_TABLE("mcp4531-502", MCP453x_502),
        MCP4531_ID_TABLE("mcp4531-103", MCP453x_103),
        MCP4531_ID_TABLE("mcp4531-503", MCP453x_503),
        MCP4531_ID_TABLE("mcp4531-104", MCP453x_104),
        MCP4531_ID_TABLE("mcp4532-502", MCP453x_502),
        MCP4531_ID_TABLE("mcp4532-103", MCP453x_103),
        MCP4531_ID_TABLE("mcp4532-503", MCP453x_503),
        MCP4531_ID_TABLE("mcp4532-104", MCP453x_104),
        MCP4531_ID_TABLE("mcp4541-502", MCP454x_502),
        MCP4531_ID_TABLE("mcp4541-103", MCP454x_103),
        MCP4531_ID_TABLE("mcp4541-503", MCP454x_503),
        MCP4531_ID_TABLE("mcp4541-104", MCP454x_104),
        MCP4531_ID_TABLE("mcp4542-502", MCP454x_502),
        MCP4531_ID_TABLE("mcp4542-103", MCP454x_103),
        MCP4531_ID_TABLE("mcp4542-503", MCP454x_503),
        MCP4531_ID_TABLE("mcp4542-104", MCP454x_104),
        MCP4531_ID_TABLE("mcp4551-502", MCP455x_502),
        MCP4531_ID_TABLE("mcp4551-103", MCP455x_103),
        MCP4531_ID_TABLE("mcp4551-503", MCP455x_503),
        MCP4531_ID_TABLE("mcp4551-104", MCP455x_104),
        MCP4531_ID_TABLE("mcp4552-502", MCP455x_502),
        MCP4531_ID_TABLE("mcp4552-103", MCP455x_103),
        MCP4531_ID_TABLE("mcp4552-503", MCP455x_503),
        MCP4531_ID_TABLE("mcp4552-104", MCP455x_104),
        MCP4531_ID_TABLE("mcp4561-502", MCP456x_502),
        MCP4531_ID_TABLE("mcp4561-103", MCP456x_103),
        MCP4531_ID_TABLE("mcp4561-503", MCP456x_503),
        MCP4531_ID_TABLE("mcp4561-104", MCP456x_104),
        MCP4531_ID_TABLE("mcp4562-502", MCP456x_502),
        MCP4531_ID_TABLE("mcp4562-103", MCP456x_103),
        MCP4531_ID_TABLE("mcp4562-503", MCP456x_503),
        MCP4531_ID_TABLE("mcp4562-104", MCP456x_104),
        MCP4531_ID_TABLE("mcp4631-502", MCP463x_502),
        MCP4531_ID_TABLE("mcp4631-103", MCP463x_103),
        MCP4531_ID_TABLE("mcp4631-503", MCP463x_503),
        MCP4531_ID_TABLE("mcp4631-104", MCP463x_104),
        MCP4531_ID_TABLE("mcp4632-502", MCP463x_502),
        MCP4531_ID_TABLE("mcp4632-103", MCP463x_103),
        MCP4531_ID_TABLE("mcp4632-503", MCP463x_503),
        MCP4531_ID_TABLE("mcp4632-104", MCP463x_104),
        MCP4531_ID_TABLE("mcp4641-502", MCP464x_502),
        MCP4531_ID_TABLE("mcp4641-103", MCP464x_103),
        MCP4531_ID_TABLE("mcp4641-503", MCP464x_503),
        MCP4531_ID_TABLE("mcp4641-104", MCP464x_104),
        MCP4531_ID_TABLE("mcp4642-502", MCP464x_502),
        MCP4531_ID_TABLE("mcp4642-103", MCP464x_103),
        MCP4531_ID_TABLE("mcp4642-503", MCP464x_503),
        MCP4531_ID_TABLE("mcp4642-104", MCP464x_104),
        MCP4531_ID_TABLE("mcp4651-502", MCP465x_502),
        MCP4531_ID_TABLE("mcp4651-103", MCP465x_103),
        MCP4531_ID_TABLE("mcp4651-503", MCP465x_503),
        MCP4531_ID_TABLE("mcp4651-104", MCP465x_104),
        MCP4531_ID_TABLE("mcp4652-502", MCP465x_502),
        MCP4531_ID_TABLE("mcp4652-103", MCP465x_103),
        MCP4531_ID_TABLE("mcp4652-503", MCP465x_503),
        MCP4531_ID_TABLE("mcp4652-104", MCP465x_104),
        MCP4531_ID_TABLE("mcp4661-502", MCP466x_502),
        MCP4531_ID_TABLE("mcp4661-103", MCP466x_103),
        MCP4531_ID_TABLE("mcp4661-503", MCP466x_503),
        MCP4531_ID_TABLE("mcp4661-104", MCP466x_104),
        MCP4531_ID_TABLE("mcp4662-502", MCP466x_502),
        MCP4531_ID_TABLE("mcp4662-103", MCP466x_103),
        MCP4531_ID_TABLE("mcp4662-503", MCP466x_503),
        MCP4531_ID_TABLE("mcp4662-104", MCP466x_104),
        { }
};
MODULE_DEVICE_TABLE(i2c, mcp4531_id);

#define MCP4531_COMPATIBLE(of_compatible, cfg) {        \
                        .compatible = of_compatible,    \
                        .data = &mcp4531_cfg[cfg],      \
}

static const struct of_device_id mcp4531_of_match[] = {
        MCP4531_COMPATIBLE("microchip,mcp4531-502", MCP453x_502),
        MCP4531_COMPATIBLE("microchip,mcp4531-103", MCP453x_103),
        MCP4531_COMPATIBLE("microchip,mcp4531-503", MCP453x_503),
        MCP4531_COMPATIBLE("microchip,mcp4531-104", MCP453x_104),
        MCP4531_COMPATIBLE("microchip,mcp4532-502", MCP453x_502),
        MCP4531_COMPATIBLE("microchip,mcp4532-103", MCP453x_103),
        MCP4531_COMPATIBLE("microchip,mcp4532-503", MCP453x_503),
        MCP4531_COMPATIBLE("microchip,mcp4532-104", MCP453x_104),
        MCP4531_COMPATIBLE("microchip,mcp4541-502", MCP454x_502),
        MCP4531_COMPATIBLE("microchip,mcp4541-103", MCP454x_103),
        MCP4531_COMPATIBLE("microchip,mcp4541-503", MCP454x_503),
        MCP4531_COMPATIBLE("microchip,mcp4541-104", MCP454x_104),
        MCP4531_COMPATIBLE("microchip,mcp4542-502", MCP454x_502),
        MCP4531_COMPATIBLE("microchip,mcp4542-103", MCP454x_103),
        MCP4531_COMPATIBLE("microchip,mcp4542-503", MCP454x_503),
        MCP4531_COMPATIBLE("microchip,mcp4542-104", MCP454x_104),
        MCP4531_COMPATIBLE("microchip,mcp4551-502", MCP455x_502),
        MCP4531_COMPATIBLE("microchip,mcp4551-103", MCP455x_103),
        MCP4531_COMPATIBLE("microchip,mcp4551-503", MCP455x_503),
        MCP4531_COMPATIBLE("microchip,mcp4551-104", MCP455x_104),
        MCP4531_COMPATIBLE("microchip,mcp4552-502", MCP455x_502),
        MCP4531_COMPATIBLE("microchip,mcp4552-103", MCP455x_103),
        MCP4531_COMPATIBLE("microchip,mcp4552-503", MCP455x_503),
        MCP4531_COMPATIBLE("microchip,mcp4552-104", MCP455x_104),
        MCP4531_COMPATIBLE("microchip,mcp4561-502", MCP456x_502),
        MCP4531_COMPATIBLE("microchip,mcp4561-103", MCP456x_103),
        MCP4531_COMPATIBLE("microchip,mcp4561-503", MCP456x_503),
        MCP4531_COMPATIBLE("microchip,mcp4561-104", MCP456x_104),
        MCP4531_COMPATIBLE("microchip,mcp4562-502", MCP456x_502),
        MCP4531_COMPATIBLE("microchip,mcp4562-103", MCP456x_103),
        MCP4531_COMPATIBLE("microchip,mcp4562-503", MCP456x_503),
        MCP4531_COMPATIBLE("microchip,mcp4562-104", MCP456x_104),
        MCP4531_COMPATIBLE("microchip,mcp4631-502", MCP463x_502),
        MCP4531_COMPATIBLE("microchip,mcp4631-103", MCP463x_103),
        MCP4531_COMPATIBLE("microchip,mcp4631-503", MCP463x_503),
        MCP4531_COMPATIBLE("microchip,mcp4631-104", MCP463x_104),
        MCP4531_COMPATIBLE("microchip,mcp4632-502", MCP463x_502),
        MCP4531_COMPATIBLE("microchip,mcp4632-103", MCP463x_103),
        MCP4531_COMPATIBLE("microchip,mcp4632-503", MCP463x_503),
        MCP4531_COMPATIBLE("microchip,mcp4632-104", MCP463x_104),
        MCP4531_COMPATIBLE("microchip,mcp4641-502", MCP464x_502),
        MCP4531_COMPATIBLE("microchip,mcp4641-103", MCP464x_103),
        MCP4531_COMPATIBLE("microchip,mcp4641-503", MCP464x_503),
        MCP4531_COMPATIBLE("microchip,mcp4641-104", MCP464x_104),
        MCP4531_COMPATIBLE("microchip,mcp4642-502", MCP464x_502),
        MCP4531_COMPATIBLE("microchip,mcp4642-103", MCP464x_103),
        MCP4531_COMPATIBLE("microchip,mcp4642-503", MCP464x_503),
        MCP4531_COMPATIBLE("microchip,mcp4642-104", MCP464x_104),
        MCP4531_COMPATIBLE("microchip,mcp4651-502", MCP465x_502),
        MCP4531_COMPATIBLE("microchip,mcp4651-103", MCP465x_103),
        MCP4531_COMPATIBLE("microchip,mcp4651-503", MCP465x_503),
        MCP4531_COMPATIBLE("microchip,mcp4651-104", MCP465x_104),
        MCP4531_COMPATIBLE("microchip,mcp4652-502", MCP465x_502),
        MCP4531_COMPATIBLE("microchip,mcp4652-103", MCP465x_103),
        MCP4531_COMPATIBLE("microchip,mcp4652-503", MCP465x_503),
        MCP4531_COMPATIBLE("microchip,mcp4652-104", MCP465x_104),
        MCP4531_COMPATIBLE("microchip,mcp4661-502", MCP466x_502),
        MCP4531_COMPATIBLE("microchip,mcp4661-103", MCP466x_103),
        MCP4531_COMPATIBLE("microchip,mcp4661-503", MCP466x_503),
        MCP4531_COMPATIBLE("microchip,mcp4661-104", MCP466x_104),
        MCP4531_COMPATIBLE("microchip,mcp4662-502", MCP466x_502),
        MCP4531_COMPATIBLE("microchip,mcp4662-103", MCP466x_103),
        MCP4531_COMPATIBLE("microchip,mcp4662-503", MCP466x_503),
        MCP4531_COMPATIBLE("microchip,mcp4662-104", MCP466x_104),
        { }
};
MODULE_DEVICE_TABLE(of, mcp4531_of_match);

static int mcp4531_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct mcp4531_data *data;
        struct iio_dev *indio_dev;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_WORD_DATA)) {
                dev_err(dev, "SMBUS Word Data not supported\n");
                return -EOPNOTSUPP;
        }

        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->client = client;

        data->cfg = i2c_get_match_data(client);

        indio_dev->info = &mcp4531_info;
        indio_dev->channels = mcp4531_channels;
        indio_dev->num_channels = data->cfg->wipers;
        indio_dev->name = client->name;

        return devm_iio_device_register(dev, indio_dev);
}

static struct i2c_driver mcp4531_driver = {
        .driver = {
                .name   = "mcp4531",
                .of_match_table = mcp4531_of_match,
        },
        .probe          = mcp4531_probe,
        .id_table       = mcp4531_id,
};

module_i2c_driver(mcp4531_driver);

MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
MODULE_DESCRIPTION("MCP4531 digital potentiometer");
MODULE_LICENSE("GPL v2");