/*
 * AD5024, AD5025, AD5044, AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R,
 * AD5648, AD5666, AD5668, AD5669R Digital to analog converters driver
 *
 * Copyright 2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/regulator/consumer.h>
#include <asm/unaligned.h>

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

#define AD5064_MAX_DAC_CHANNELS                 8
#define AD5064_MAX_VREFS                        4

#define AD5064_ADDR(x)                          ((x) << 20)
#define AD5064_CMD(x)                           ((x) << 24)

#define AD5064_ADDR_ALL_DAC                     0xF

#define AD5064_CMD_WRITE_INPUT_N                0x0
#define AD5064_CMD_UPDATE_DAC_N                 0x1
#define AD5064_CMD_WRITE_INPUT_N_UPDATE_ALL     0x2
#define AD5064_CMD_WRITE_INPUT_N_UPDATE_N       0x3
#define AD5064_CMD_POWERDOWN_DAC                0x4
#define AD5064_CMD_CLEAR                        0x5
#define AD5064_CMD_LDAC_MASK                    0x6
#define AD5064_CMD_RESET                        0x7
#define AD5064_CMD_CONFIG                       0x8

#define AD5064_CONFIG_DAISY_CHAIN_ENABLE        BIT(1)
#define AD5064_CONFIG_INT_VREF_ENABLE           BIT(0)

#define AD5064_LDAC_PWRDN_NONE                  0x0
#define AD5064_LDAC_PWRDN_1K                    0x1
#define AD5064_LDAC_PWRDN_100K                  0x2
#define AD5064_LDAC_PWRDN_3STATE                0x3

/**
 * struct ad5064_chip_info - chip specific information
 * @shared_vref:        whether the vref supply is shared between channels
 * @internal_vref:      internal reference voltage. 0 if the chip has no internal
 *                      vref.
 * @channel:            channel specification
 * @num_channels:       number of channels
 */

struct ad5064_chip_info {
        bool shared_vref;
        unsigned long internal_vref;
        const struct iio_chan_spec *channels;
        unsigned int num_channels;
};

struct ad5064_state;

typedef int (*ad5064_write_func)(struct ad5064_state *st, unsigned int cmd,
                unsigned int addr, unsigned int val);

/**
 * struct ad5064_state - driver instance specific data
 * @dev:                the device for this driver instance
 * @chip_info:          chip model specific constants, available modes etc
 * @vref_reg:           vref supply regulators
 * @pwr_down:           whether channel is powered down
 * @pwr_down_mode:      channel's current power down mode
 * @dac_cache:          current DAC raw value (chip does not support readback)
 * @use_internal_vref:  set to true if the internal reference voltage should be
 *                      used.
 * @write:              register write callback
 * @data:               i2c/spi transfer buffers
 */

struct ad5064_state {
        struct device                   *dev;
        const struct ad5064_chip_info   *chip_info;
        struct regulator_bulk_data      vref_reg[AD5064_MAX_VREFS];
        bool                            pwr_down[AD5064_MAX_DAC_CHANNELS];
        u8                              pwr_down_mode[AD5064_MAX_DAC_CHANNELS];
        unsigned int                    dac_cache[AD5064_MAX_DAC_CHANNELS];
        bool                            use_internal_vref;

        ad5064_write_func               write;

        /*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
         */
        union {
                u8 i2c[3];
                __be32 spi;
        } data ____cacheline_aligned;
};

enum ad5064_type {
        ID_AD5024,
        ID_AD5025,
        ID_AD5044,
        ID_AD5045,
        ID_AD5064,
        ID_AD5064_1,
        ID_AD5065,
        ID_AD5628_1,
        ID_AD5628_2,
        ID_AD5648_1,
        ID_AD5648_2,
        ID_AD5666_1,
        ID_AD5666_2,
        ID_AD5668_1,
        ID_AD5668_2,
};

static int ad5064_write(struct ad5064_state *st, unsigned int cmd,
        unsigned int addr, unsigned int val, unsigned int shift)
{
        val <<= shift;

        return st->write(st, cmd, addr, val);
}

static int ad5064_sync_powerdown_mode(struct ad5064_state *st,
        const struct iio_chan_spec *chan)
{
        unsigned int val;
        int ret;

        val = (0x1 << chan->address);

        if (st->pwr_down[chan->channel])
                val |= st->pwr_down_mode[chan->channel] << 8;

        ret = ad5064_write(st, AD5064_CMD_POWERDOWN_DAC, 0, val, 0);

        return ret;
}

static const char * const ad5064_powerdown_modes[] = {
        "1kohm_to_gnd",
        "100kohm_to_gnd",
        "three_state",
};

static int ad5064_get_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan)
{
        struct ad5064_state *st = iio_priv(indio_dev);

        return st->pwr_down_mode[chan->channel] - 1;
}

static int ad5064_set_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, unsigned int mode)
{
        struct ad5064_state *st = iio_priv(indio_dev);
        int ret;

        mutex_lock(&indio_dev->mlock);
        st->pwr_down_mode[chan->channel] = mode + 1;

        ret = ad5064_sync_powerdown_mode(st, chan);
        mutex_unlock(&indio_dev->mlock);

        return ret;
}

static const struct iio_enum ad5064_powerdown_mode_enum = {
        .items = ad5064_powerdown_modes,
        .num_items = ARRAY_SIZE(ad5064_powerdown_modes),
        .get = ad5064_get_powerdown_mode,
        .set = ad5064_set_powerdown_mode,
};

static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
        uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
        struct ad5064_state *st = iio_priv(indio_dev);

        return sprintf(buf, "%d\n", st->pwr_down[chan->channel]);
}

static ssize_t ad5064_write_dac_powerdown(struct iio_dev *indio_dev,
         uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
         size_t len)
{
        struct ad5064_state *st = iio_priv(indio_dev);
        bool pwr_down;
        int ret;

        ret = strtobool(buf, &pwr_down);
        if (ret)
                return ret;

        mutex_lock(&indio_dev->mlock);
        st->pwr_down[chan->channel] = pwr_down;

        ret = ad5064_sync_powerdown_mode(st, chan);
        mutex_unlock(&indio_dev->mlock);
        return ret ? ret : len;
}

static int ad5064_get_vref(struct ad5064_state *st,
        struct iio_chan_spec const *chan)
{
        unsigned int i;

        if (st->use_internal_vref)
                return st->chip_info->internal_vref;

        i = st->chip_info->shared_vref ? 0 : chan->channel;
        return regulator_get_voltage(st->vref_reg[i].consumer);
}

static int ad5064_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val,
                           int *val2,
                           long m)
{
        struct ad5064_state *st = iio_priv(indio_dev);
        int scale_uv;

        switch (m) {
        case IIO_CHAN_INFO_RAW:
                *val = st->dac_cache[chan->channel];
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                scale_uv = ad5064_get_vref(st, chan);
                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 ad5064_write_raw(struct iio_dev *indio_dev,
        struct iio_chan_spec const *chan, int val, int val2, long mask)
{
        struct ad5064_state *st = iio_priv(indio_dev);
        int ret;

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

                mutex_lock(&indio_dev->mlock);
                ret = ad5064_write(st, AD5064_CMD_WRITE_INPUT_N_UPDATE_N,
                                chan->address, val, chan->scan_type.shift);
                if (ret == 0)
                        st->dac_cache[chan->channel] = val;
                mutex_unlock(&indio_dev->mlock);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static const struct iio_info ad5064_info = {
        .read_raw = ad5064_read_raw,
        .write_raw = ad5064_write_raw,
        .driver_module = THIS_MODULE,
};

static const struct iio_chan_spec_ext_info ad5064_ext_info[] = {
        {
                .name = "powerdown",
                .read = ad5064_read_dac_powerdown,
                .write = ad5064_write_dac_powerdown,
                .shared = IIO_SEPARATE,
        },
        IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ad5064_powerdown_mode_enum),
        IIO_ENUM_AVAILABLE("powerdown_mode", &ad5064_powerdown_mode_enum),
        { },
};

#define AD5064_CHANNEL(chan, addr, bits) {                      \
        .type = IIO_VOLTAGE,                                    \
        .indexed = 1,                                           \
        .output = 1,                                            \
        .channel = (chan),                                      \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
        BIT(IIO_CHAN_INFO_SCALE),                                       \
        .address = addr,                                        \
        .scan_type = {                                          \
                .sign = 'u',                                    \
                .realbits = (bits),                             \
                .storagebits = 16,                              \
                .shift = 20 - bits,                             \
        },                                                      \
        .ext_info = ad5064_ext_info,                            \
}

#define DECLARE_AD5064_CHANNELS(name, bits) \
const struct iio_chan_spec name[] = { \
        AD5064_CHANNEL(0, 0, bits), \
        AD5064_CHANNEL(1, 1, bits), \
        AD5064_CHANNEL(2, 2, bits), \
        AD5064_CHANNEL(3, 3, bits), \
        AD5064_CHANNEL(4, 4, bits), \
        AD5064_CHANNEL(5, 5, bits), \
        AD5064_CHANNEL(6, 6, bits), \
        AD5064_CHANNEL(7, 7, bits), \
}

#define DECLARE_AD5065_CHANNELS(name, bits) \
const struct iio_chan_spec name[] = { \
        AD5064_CHANNEL(0, 0, bits), \
        AD5064_CHANNEL(1, 3, bits), \
}

static DECLARE_AD5064_CHANNELS(ad5024_channels, 12);
static DECLARE_AD5064_CHANNELS(ad5044_channels, 14);
static DECLARE_AD5064_CHANNELS(ad5064_channels, 16);

static DECLARE_AD5065_CHANNELS(ad5025_channels, 12);
static DECLARE_AD5065_CHANNELS(ad5045_channels, 14);
static DECLARE_AD5065_CHANNELS(ad5065_channels, 16);

static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
        [ID_AD5024] = {
                .shared_vref = false,
                .channels = ad5024_channels,
                .num_channels = 4,
        },
        [ID_AD5025] = {
                .shared_vref = false,
                .channels = ad5025_channels,
                .num_channels = 2,
        },
        [ID_AD5044] = {
                .shared_vref = false,
                .channels = ad5044_channels,
                .num_channels = 4,
        },
        [ID_AD5045] = {
                .shared_vref = false,
                .channels = ad5045_channels,
                .num_channels = 2,
        },
        [ID_AD5064] = {
                .shared_vref = false,
                .channels = ad5064_channels,
                .num_channels = 4,
        },
        [ID_AD5064_1] = {
                .shared_vref = true,
                .channels = ad5064_channels,
                .num_channels = 4,
        },
        [ID_AD5065] = {
                .shared_vref = false,
                .channels = ad5065_channels,
                .num_channels = 2,
        },
        [ID_AD5628_1] = {
                .shared_vref = true,
                .internal_vref = 2500000,
                .channels = ad5024_channels,
                .num_channels = 8,
        },
        [ID_AD5628_2] = {
                .shared_vref = true,
                .internal_vref = 5000000,
                .channels = ad5024_channels,
                .num_channels = 8,
        },
        [ID_AD5648_1] = {
                .shared_vref = true,
                .internal_vref = 2500000,
                .channels = ad5044_channels,
                .num_channels = 8,
        },
        [ID_AD5648_2] = {
                .shared_vref = true,
                .internal_vref = 5000000,
                .channels = ad5044_channels,
                .num_channels = 8,
        },
        [ID_AD5666_1] = {
                .shared_vref = true,
                .internal_vref = 2500000,
                .channels = ad5064_channels,
                .num_channels = 4,
        },
        [ID_AD5666_2] = {
                .shared_vref = true,
                .internal_vref = 5000000,
                .channels = ad5064_channels,
                .num_channels = 4,
        },
        [ID_AD5668_1] = {
                .shared_vref = true,
                .internal_vref = 2500000,
                .channels = ad5064_channels,
                .num_channels = 8,
        },
        [ID_AD5668_2] = {
                .shared_vref = true,
                .internal_vref = 5000000,
                .channels = ad5064_channels,
                .num_channels = 8,
        },
};

static inline unsigned int ad5064_num_vref(struct ad5064_state *st)
{
        return st->chip_info->shared_vref ? 1 : st->chip_info->num_channels;
}

static const char * const ad5064_vref_names[] = {
        "vrefA",
        "vrefB",
        "vrefC",
        "vrefD",
};

static const char * const ad5064_vref_name(struct ad5064_state *st,
        unsigned int vref)
{
        return st->chip_info->shared_vref ? "vref" : ad5064_vref_names[vref];
}

static int ad5064_probe(struct device *dev, enum ad5064_type type,
                        const char *name, ad5064_write_func write)
{
        struct iio_dev *indio_dev;
        struct ad5064_state *st;
        unsigned int midscale;
        unsigned int i;
        int ret;

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

        st = iio_priv(indio_dev);
        dev_set_drvdata(dev, indio_dev);

        st->chip_info = &ad5064_chip_info_tbl[type];
        st->dev = dev;
        st->write = write;

        for (i = 0; i < ad5064_num_vref(st); ++i)
                st->vref_reg[i].supply = ad5064_vref_name(st, i);

        ret = devm_regulator_bulk_get(dev, ad5064_num_vref(st),
                st->vref_reg);
        if (ret) {
                if (!st->chip_info->internal_vref)
                        return ret;
                st->use_internal_vref = true;
                ret = ad5064_write(st, AD5064_CMD_CONFIG, 0,
                        AD5064_CONFIG_INT_VREF_ENABLE, 0);
                if (ret) {
                        dev_err(dev, "Failed to enable internal vref: %d\n",
                                ret);
                        return ret;
                }
        } else {
                ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
                if (ret)
                        return ret;
        }

        indio_dev->dev.parent = dev;
        indio_dev->name = name;
        indio_dev->info = &ad5064_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = st->chip_info->channels;
        indio_dev->num_channels = st->chip_info->num_channels;

        midscale = (1 << indio_dev->channels[0].scan_type.realbits) /  2;

        for (i = 0; i < st->chip_info->num_channels; ++i) {
                st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
                st->dac_cache[i] = midscale;
        }

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

        return 0;

error_disable_reg:
        if (!st->use_internal_vref)
                regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);

        return ret;
}

static int ad5064_remove(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct ad5064_state *st = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        if (!st->use_internal_vref)
                regulator_bulk_disable(ad5064_num_vref(st), st->vref_reg);

        return 0;
}

#if IS_ENABLED(CONFIG_SPI_MASTER)

static int ad5064_spi_write(struct ad5064_state *st, unsigned int cmd,
        unsigned int addr, unsigned int val)
{
        struct spi_device *spi = to_spi_device(st->dev);

        st->data.spi = cpu_to_be32(AD5064_CMD(cmd) | AD5064_ADDR(addr) | val);
        return spi_write(spi, &st->data.spi, sizeof(st->data.spi));
}

static int ad5064_spi_probe(struct spi_device *spi)
{
        const struct spi_device_id *id = spi_get_device_id(spi);

        return ad5064_probe(&spi->dev, id->driver_data, id->name,
                                ad5064_spi_write);
}

static int ad5064_spi_remove(struct spi_device *spi)
{
        return ad5064_remove(&spi->dev);
}

static const struct spi_device_id ad5064_spi_ids[] = {
        {"ad5024", ID_AD5024},
        {"ad5025", ID_AD5025},
        {"ad5044", ID_AD5044},
        {"ad5045", ID_AD5045},
        {"ad5064", ID_AD5064},
        {"ad5064-1", ID_AD5064_1},
        {"ad5065", ID_AD5065},
        {"ad5628-1", ID_AD5628_1},
        {"ad5628-2", ID_AD5628_2},
        {"ad5648-1", ID_AD5648_1},
        {"ad5648-2", ID_AD5648_2},
        {"ad5666-1", ID_AD5666_1},
        {"ad5666-2", ID_AD5666_2},
        {"ad5668-1", ID_AD5668_1},
        {"ad5668-2", ID_AD5668_2},
        {"ad5668-3", ID_AD5668_2}, /* similar enough to ad5668-2 */
        {}
};
MODULE_DEVICE_TABLE(spi, ad5064_spi_ids);

static struct spi_driver ad5064_spi_driver = {
        .driver = {
                   .name = "ad5064",
                   .owner = THIS_MODULE,
        },
        .probe = ad5064_spi_probe,
        .remove = ad5064_spi_remove,
        .id_table = ad5064_spi_ids,
};

static int __init ad5064_spi_register_driver(void)
{
        return spi_register_driver(&ad5064_spi_driver);
}

static void ad5064_spi_unregister_driver(void)
{
        spi_unregister_driver(&ad5064_spi_driver);
}

#else

static inline int ad5064_spi_register_driver(void) { return 0; }
static inline void ad5064_spi_unregister_driver(void) { }

#endif

#if IS_ENABLED(CONFIG_I2C)

static int ad5064_i2c_write(struct ad5064_state *st, unsigned int cmd,
        unsigned int addr, unsigned int val)
{
        struct i2c_client *i2c = to_i2c_client(st->dev);

        st->data.i2c[0] = (cmd << 4) | addr;
        put_unaligned_be16(val, &st->data.i2c[1]);
        return i2c_master_send(i2c, st->data.i2c, 3);
}

static int ad5064_i2c_probe(struct i2c_client *i2c,
        const struct i2c_device_id *id)
{
        return ad5064_probe(&i2c->dev, id->driver_data, id->name,
                                                ad5064_i2c_write);
}

static int ad5064_i2c_remove(struct i2c_client *i2c)
{
        return ad5064_remove(&i2c->dev);
}

static const struct i2c_device_id ad5064_i2c_ids[] = {
        {"ad5629-1", ID_AD5628_1},
        {"ad5629-2", ID_AD5628_2},
        {"ad5629-3", ID_AD5628_2}, /* similar enough to ad5629-2 */
        {"ad5669-1", ID_AD5668_1},
        {"ad5669-2", ID_AD5668_2},
        {"ad5669-3", ID_AD5668_2}, /* similar enough to ad5669-2 */
        {}
};
MODULE_DEVICE_TABLE(i2c, ad5064_i2c_ids);

static struct i2c_driver ad5064_i2c_driver = {
        .driver = {
                   .name = "ad5064",
                   .owner = THIS_MODULE,
        },
        .probe = ad5064_i2c_probe,
        .remove = ad5064_i2c_remove,
        .id_table = ad5064_i2c_ids,
};

static int __init ad5064_i2c_register_driver(void)
{
        return i2c_add_driver(&ad5064_i2c_driver);
}

static void __exit ad5064_i2c_unregister_driver(void)
{
        i2c_del_driver(&ad5064_i2c_driver);
}

#else

static inline int ad5064_i2c_register_driver(void) { return 0; }
static inline void ad5064_i2c_unregister_driver(void) { }

#endif

static int __init ad5064_init(void)
{
        int ret;

        ret = ad5064_spi_register_driver();
        if (ret)
                return ret;

        ret = ad5064_i2c_register_driver();
        if (ret) {
                ad5064_spi_unregister_driver();
                return ret;
        }

        return 0;
}
module_init(ad5064_init);

static void __exit ad5064_exit(void)
{
        ad5064_i2c_unregister_driver();
        ad5064_spi_unregister_driver();
}
module_exit(ad5064_exit);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD5024 and similar multi-channel DACs");
MODULE_LICENSE("GPL v2");