// SPDX-License-Identifier: GPL-2.0-only
/*
 * AD5415, AD5426, AD5429, AD5432, AD5439, AD5443, AD5449 Digital to Analog
 * Converter driver.
 *
 * Copyright 2012 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <lars@metafoo.de>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/regulator/consumer.h>
#include <linux/unaligned.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define AD5449_MAX_CHANNELS             2
#define AD5449_MAX_VREFS                2

#define AD5449_CMD_NOOP                 0x0
#define AD5449_CMD_LOAD_AND_UPDATE(x)   (0x1 + (x) * 3)
#define AD5449_CMD_READ(x)              (0x2 + (x) * 3)
#define AD5449_CMD_LOAD(x)              (0x3 + (x) * 3)
#define AD5449_CMD_CTRL                 13

#define AD5449_CTRL_SDO_OFFSET          10
#define AD5449_CTRL_DAISY_CHAIN         BIT(9)
#define AD5449_CTRL_HCLR_TO_MIDSCALE    BIT(8)
#define AD5449_CTRL_SAMPLE_RISING       BIT(7)

/**
 * struct ad5449_chip_info - chip specific information
 * @channels:           Channel specification
 * @num_channels:       Number of channels
 * @has_ctrl:           Chip has a control register
 */
struct ad5449_chip_info {
        const struct iio_chan_spec *channels;
        unsigned int num_channels;
        bool has_ctrl;
};

/**
 * struct ad5449 - driver instance specific data
 * @spi:                the SPI device for this driver instance
 * @chip_info:          chip model specific constants, available modes etc
 * @vref_reg:           vref supply regulators
 * @has_sdo:            whether the SDO line is connected
 * @dac_cache:          Cache for the DAC values
 * @data:               spi transfer buffers
 * @lock:               lock to protect the data buffer during SPI ops
 */
struct ad5449 {
        struct spi_device               *spi;
        const struct ad5449_chip_info   *chip_info;
        struct regulator_bulk_data      vref_reg[AD5449_MAX_VREFS];
        struct mutex                    lock;

        bool has_sdo;
        uint16_t dac_cache[AD5449_MAX_CHANNELS];

        /*
         * DMA (thus cache coherency maintenance) may require the
         * transfer buffers to live in their own cache lines.
         */
        __be16 data[2] __aligned(IIO_DMA_MINALIGN);
};

enum ad5449_type {
        ID_AD5426,
        ID_AD5429,
        ID_AD5432,
        ID_AD5439,
        ID_AD5443,
        ID_AD5449,
};

static int ad5449_write(struct iio_dev *indio_dev, unsigned int addr,
        unsigned int val)
{
        struct ad5449 *st = iio_priv(indio_dev);
        int ret;

        mutex_lock(&st->lock);
        st->data[0] = cpu_to_be16((addr << 12) | val);
        ret = spi_write(st->spi, st->data, 2);
        mutex_unlock(&st->lock);

        return ret;
}

static int ad5449_read(struct iio_dev *indio_dev, unsigned int addr,
        unsigned int *val)
{
        struct ad5449 *st = iio_priv(indio_dev);
        int ret;
        struct spi_transfer t[] = {
                {
                        .tx_buf = &st->data[0],
                        .len = 2,
                        .cs_change = 1,
                }, {
                        .tx_buf = &st->data[1],
                        .rx_buf = &st->data[1],
                        .len = 2,
                },
        };

        mutex_lock(&st->lock);
        st->data[0] = cpu_to_be16(addr << 12);
        st->data[1] = cpu_to_be16(AD5449_CMD_NOOP);

        ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
        if (ret < 0)
                goto out_unlock;

        *val = be16_to_cpu(st->data[1]);

out_unlock:
        mutex_unlock(&st->lock);
        return ret;
}

static int ad5449_read_raw(struct iio_dev *indio_dev,
        struct iio_chan_spec const *chan, int *val, int *val2, long info)
{
        struct ad5449 *st = iio_priv(indio_dev);
        struct regulator_bulk_data *reg;
        int scale_uv;
        int ret;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                if (st->has_sdo) {
                        ret = ad5449_read(indio_dev,
                                AD5449_CMD_READ(chan->address), val);
                        if (ret)
                                return ret;
                        *val &= 0xfff;
                } else {
                        *val = st->dac_cache[chan->address];
                }

                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                reg = &st->vref_reg[chan->channel];
                scale_uv = regulator_get_voltage(reg->consumer);
                if (scale_uv < 0)
                        return scale_uv;

                *val = scale_uv / 1000;
                *val2 = chan->scan_type.realbits;

                return IIO_VAL_FRACTIONAL_LOG2;
        default:
                break;
        }

        return -EINVAL;
}

static int ad5449_write_raw(struct iio_dev *indio_dev,
        struct iio_chan_spec const *chan, int val, int val2, long info)
{
        struct ad5449 *st = iio_priv(indio_dev);
        int ret;

        switch (info) {
        case IIO_CHAN_INFO_RAW:
                if (val < 0 || val >= (1 << chan->scan_type.realbits))
                        return -EINVAL;

                ret = ad5449_write(indio_dev,
                        AD5449_CMD_LOAD_AND_UPDATE(chan->address),
                        val << chan->scan_type.shift);
                if (ret == 0)
                        st->dac_cache[chan->address] = val;
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static const struct iio_info ad5449_info = {
        .read_raw = ad5449_read_raw,
        .write_raw = ad5449_write_raw,
};

#define AD5449_CHANNEL(chan, bits) {                            \
        .type = IIO_VOLTAGE,                                    \
        .indexed = 1,                                           \
        .output = 1,                                            \
        .channel = (chan),                                      \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
                BIT(IIO_CHAN_INFO_SCALE),                       \
        .address = (chan),                                      \
        .scan_type = {                                          \
                .sign = 'u',                                    \
                .realbits = (bits),                             \
                .storagebits = 16,                              \
                .shift = 12 - (bits),                           \
        },                                                      \
}

#define DECLARE_AD5449_CHANNELS(name, bits) \
const struct iio_chan_spec name[] = { \
        AD5449_CHANNEL(0, bits), \
        AD5449_CHANNEL(1, bits), \
}

static DECLARE_AD5449_CHANNELS(ad5429_channels, 8);
static DECLARE_AD5449_CHANNELS(ad5439_channels, 10);
static DECLARE_AD5449_CHANNELS(ad5449_channels, 12);

static const struct ad5449_chip_info ad5449_chip_info[] = {
        [ID_AD5426] = {
                .channels = ad5429_channels,
                .num_channels = 1,
                .has_ctrl = false,
        },
        [ID_AD5429] = {
                .channels = ad5429_channels,
                .num_channels = 2,
                .has_ctrl = true,
        },
        [ID_AD5432] = {
                .channels = ad5439_channels,
                .num_channels = 1,
                .has_ctrl = false,
        },
        [ID_AD5439] = {
                .channels = ad5439_channels,
                .num_channels = 2,
                .has_ctrl = true,
        },
        [ID_AD5443] = {
                .channels = ad5449_channels,
                .num_channels = 1,
                .has_ctrl = false,
        },
        [ID_AD5449] = {
                .channels = ad5449_channels,
                .num_channels = 2,
                .has_ctrl = true,
        },
};

static const char *ad5449_vref_name(struct ad5449 *st, int n)
{
        if (st->chip_info->num_channels == 1)
                return "VREF";

        if (n == 0)
                return "VREFA";
        else
                return "VREFB";
}

static int ad5449_spi_probe(struct spi_device *spi)
{
        const struct spi_device_id *id = spi_get_device_id(spi);
        struct iio_dev *indio_dev;
        struct ad5449 *st;
        unsigned int i;
        int ret;

        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
        if (indio_dev == NULL)
                return -ENOMEM;

        st = iio_priv(indio_dev);
        spi_set_drvdata(spi, indio_dev);

        st->chip_info = &ad5449_chip_info[id->driver_data];
        st->spi = spi;

        for (i = 0; i < st->chip_info->num_channels; ++i)
                st->vref_reg[i].supply = ad5449_vref_name(st, i);

        ret = devm_regulator_bulk_get(&spi->dev, st->chip_info->num_channels,
                                st->vref_reg);
        if (ret)
                return ret;

        ret = regulator_bulk_enable(st->chip_info->num_channels, st->vref_reg);
        if (ret)
                return ret;

        indio_dev->name = id->name;
        indio_dev->info = &ad5449_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = st->chip_info->channels;
        indio_dev->num_channels = st->chip_info->num_channels;

        mutex_init(&st->lock);

        if (st->chip_info->has_ctrl) {
                st->has_sdo = true;
                ad5449_write(indio_dev, AD5449_CMD_CTRL, 0x0);
        }

        ret = iio_device_register(indio_dev);
        if (ret)
                goto error_disable_reg;

        return 0;

error_disable_reg:
        regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);

        return ret;
}

static void ad5449_spi_remove(struct spi_device *spi)
{
        struct iio_dev *indio_dev = spi_get_drvdata(spi);
        struct ad5449 *st = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        regulator_bulk_disable(st->chip_info->num_channels, st->vref_reg);
}

static const struct spi_device_id ad5449_spi_ids[] = {
        { "ad5415", ID_AD5449 },
        { "ad5426", ID_AD5426 },
        { "ad5429", ID_AD5429 },
        { "ad5432", ID_AD5432 },
        { "ad5439", ID_AD5439 },
        { "ad5443", ID_AD5443 },
        { "ad5449", ID_AD5449 },
        { }
};
MODULE_DEVICE_TABLE(spi, ad5449_spi_ids);

static struct spi_driver ad5449_spi_driver = {
        .driver = {
                .name = "ad5449",
        },
        .probe = ad5449_spi_probe,
        .remove = ad5449_spi_remove,
        .id_table = ad5449_spi_ids,
};
module_spi_driver(ad5449_spi_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD5449 and similar DACs");
MODULE_LICENSE("GPL v2");