ad5791.c

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/*
 * AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
 * Converter
 *
 * Copyright 2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/device.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/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/dac/ad5791.h>

#define AD5791_RES_MASK(x)      ((1 << (x)) - 1)
#define AD5791_DAC_MASK         AD5791_RES_MASK(20)
#define AD5791_DAC_MSB          (1 << 19)

#define AD5791_CMD_READ         (1 << 23)
#define AD5791_CMD_WRITE        (0 << 23)
#define AD5791_ADDR(addr)       ((addr) << 20)

/* Registers */
#define AD5791_ADDR_NOOP        0
#define AD5791_ADDR_DAC0        1
#define AD5791_ADDR_CTRL        2
#define AD5791_ADDR_CLRCODE     3
#define AD5791_ADDR_SW_CTRL     4

/* Control Register */
#define AD5791_CTRL_RBUF        (1 << 1)
#define AD5791_CTRL_OPGND       (1 << 2)
#define AD5791_CTRL_DACTRI      (1 << 3)
#define AD5791_CTRL_BIN2SC      (1 << 4)
#define AD5791_CTRL_SDODIS      (1 << 5)
#define AD5761_CTRL_LINCOMP(x)      ((x) << 6)

#define AD5791_LINCOMP_0_10     0
#define AD5791_LINCOMP_10_12        1
#define AD5791_LINCOMP_12_16        2
#define AD5791_LINCOMP_16_19        3
#define AD5791_LINCOMP_19_20        12

#define AD5780_LINCOMP_0_10     0
#define AD5780_LINCOMP_10_20        12

/* Software Control Register */
#define AD5791_SWCTRL_LDAC      (1 << 0)
#define AD5791_SWCTRL_CLR       (1 << 1)
#define AD5791_SWCTRL_RESET     (1 << 2)

#define AD5791_DAC_PWRDN_6K     0
#define AD5791_DAC_PWRDN_3STATE     1

struct ad5791_chip_info {
    int (*get_lin_comp) (unsigned int span);
};

struct ad5791_state {
    struct spi_device       *spi;
    struct regulator        *reg_vdd;
    struct regulator        *reg_vss;
    const struct ad5791_chip_info   *chip_info;
    unsigned short          vref_mv;
    unsigned int            vref_neg_mv;
    unsigned            ctrl;
    unsigned            pwr_down_mode;
    bool                pwr_down;
};

enum ad5791_supported_device_ids {
    ID_AD5760,
    ID_AD5780,
    ID_AD5781,
    ID_AD5791,
};

static int ad5791_spi_write(struct spi_device *spi, u8 addr, u32 val)
{
    union {
        u32 d32;
        u8 d8[4];
    } data;

    data.d32 = cpu_to_be32(AD5791_CMD_WRITE |
                  AD5791_ADDR(addr) |
                  (val & AD5791_DAC_MASK));

    return spi_write(spi, &data.d8[1], 3);
}

static int ad5791_spi_read(struct spi_device *spi, u8 addr, u32 *val)
{
    union {
        u32 d32;
        u8 d8[4];
    } data[3];
    int ret;
    struct spi_message msg;
    struct spi_transfer xfers[] = {
        {
            .tx_buf = &data[0].d8[1],
            .bits_per_word = 8,
            .len = 3,
            .cs_change = 1,
        }, {
            .tx_buf = &data[1].d8[1],
            .rx_buf = &data[2].d8[1],
            .bits_per_word = 8,
            .len = 3,
        },
    };

    data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
                  AD5791_ADDR(addr));
    data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));

    spi_message_init(&msg);
    spi_message_add_tail(&xfers[0], &msg);
    spi_message_add_tail(&xfers[1], &msg);
    ret = spi_sync(spi, &msg);

    *val = be32_to_cpu(data[2].d32);

    return ret;
}

static const char * const ad5791_powerdown_modes[] = {
    "6kohm_to_gnd",
    "three_state",
};

static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
    const struct iio_chan_spec *chan)
{
    struct ad5791_state *st = iio_priv(indio_dev);

    return st->pwr_down_mode;
}

static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
    const struct iio_chan_spec *chan, unsigned int mode)
{
    struct ad5791_state *st = iio_priv(indio_dev);

    st->pwr_down_mode = mode;

    return 0;
}

static const struct iio_enum ad5791_powerdown_mode_enum = {
    .items = ad5791_powerdown_modes,
    .num_items = ARRAY_SIZE(ad5791_powerdown_modes),
    .get = ad5791_get_powerdown_mode,
    .set = ad5791_set_powerdown_mode,
};

static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
    uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
    struct ad5791_state *st = iio_priv(indio_dev);

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

static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
     uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
     size_t len)
{
    bool pwr_down;
    int ret;
    struct ad5791_state *st = iio_priv(indio_dev);

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

    if (!pwr_down) {
        st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
    } else {
        if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
            st->ctrl |= AD5791_CTRL_OPGND;
        else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
            st->ctrl |= AD5791_CTRL_DACTRI;
    }
    st->pwr_down = pwr_down;

    ret = ad5791_spi_write(st->spi, AD5791_ADDR_CTRL, st->ctrl);

    return ret ? ret : len;
}

static int ad5791_get_lin_comp(unsigned int span)
{
    if (span <= 10000)
        return AD5791_LINCOMP_0_10;
    else if (span <= 12000)
        return AD5791_LINCOMP_10_12;
    else if (span <= 16000)
        return AD5791_LINCOMP_12_16;
    else if (span <= 19000)
        return AD5791_LINCOMP_16_19;
    else
        return AD5791_LINCOMP_19_20;
}

static int ad5780_get_lin_comp(unsigned int span)
{
    if (span <= 10000)
        return AD5780_LINCOMP_0_10;
    else
        return AD5780_LINCOMP_10_20;
}
static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
    [ID_AD5760] = {
        .get_lin_comp = ad5780_get_lin_comp,
    },
    [ID_AD5780] = {
        .get_lin_comp = ad5780_get_lin_comp,
    },
    [ID_AD5781] = {
        .get_lin_comp = ad5791_get_lin_comp,
    },
    [ID_AD5791] = {
        .get_lin_comp = ad5791_get_lin_comp,
    },
};

static int ad5791_read_raw(struct iio_dev *indio_dev,
               struct iio_chan_spec const *chan,
               int *val,
               int *val2,
               long m)
{
    struct ad5791_state *st = iio_priv(indio_dev);
    u64 val64;
    int ret;

    switch (m) {
    case IIO_CHAN_INFO_RAW:
        ret = ad5791_spi_read(st->spi, chan->address, val);
        if (ret)
            return ret;
        *val &= AD5791_DAC_MASK;
        *val >>= chan->scan_type.shift;
        return IIO_VAL_INT;
    case IIO_CHAN_INFO_SCALE:
        *val = 0;
        *val2 = (((u64)st->vref_mv) * 1000000ULL) >> chan->scan_type.realbits;
        return IIO_VAL_INT_PLUS_MICRO;
    case IIO_CHAN_INFO_OFFSET:
        val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
        do_div(val64, st->vref_mv);
        *val = -val64;
        return IIO_VAL_INT;
    default:
        return -EINVAL;
    }

};

static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
    {
        .name = "powerdown",
        .shared = true,
        .read = ad5791_read_dac_powerdown,
        .write = ad5791_write_dac_powerdown,
    },
    IIO_ENUM("powerdown_mode", true, &ad5791_powerdown_mode_enum),
    IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
    { },
};

#define AD5791_CHAN(bits, shift) {          \
    .type = IIO_VOLTAGE,                \
    .output = 1,                    \
    .indexed = 1,                   \
    .address = AD5791_ADDR_DAC0,            \
    .channel = 0,                   \
    .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |   \
        IIO_CHAN_INFO_SCALE_SHARED_BIT |    \
        IIO_CHAN_INFO_OFFSET_SHARED_BIT,    \
    .scan_type = IIO_ST('u', bits, 24, shift),  \
    .ext_info = ad5791_ext_info,            \
}

static const struct iio_chan_spec ad5791_channels[] = {
    [ID_AD5760] = AD5791_CHAN(16, 4),
    [ID_AD5780] = AD5791_CHAN(18, 2),
    [ID_AD5781] = AD5791_CHAN(18, 2),
    [ID_AD5791] = AD5791_CHAN(20, 0)
};

static int ad5791_write_raw(struct iio_dev *indio_dev,
                struct iio_chan_spec const *chan,
                int val,
                int val2,
                long mask)
{
    struct ad5791_state *st = iio_priv(indio_dev);

    switch (mask) {
    case IIO_CHAN_INFO_RAW:
        val &= AD5791_RES_MASK(chan->scan_type.realbits);
        val <<= chan->scan_type.shift;

        return ad5791_spi_write(st->spi, chan->address, val);

    default:
        return -EINVAL;
    }
}

static const struct iio_info ad5791_info = {
    .read_raw = &ad5791_read_raw,
    .write_raw = &ad5791_write_raw,
    .driver_module = THIS_MODULE,
};

static int __devinit ad5791_probe(struct spi_device *spi)
{
    struct ad5791_platform_data *pdata = spi->dev.platform_data;
    struct iio_dev *indio_dev;
    struct ad5791_state *st;
    int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;

    indio_dev = iio_device_alloc(sizeof(*st));
    if (indio_dev == NULL) {
        ret = -ENOMEM;
        goto error_ret;
    }
    st = iio_priv(indio_dev);
    st->reg_vdd = regulator_get(&spi->dev, "vdd");
    if (!IS_ERR(st->reg_vdd)) {
        ret = regulator_enable(st->reg_vdd);
        if (ret)
            goto error_put_reg_pos;

        pos_voltage_uv = regulator_get_voltage(st->reg_vdd);
    }

    st->reg_vss = regulator_get(&spi->dev, "vss");
    if (!IS_ERR(st->reg_vss)) {
        ret = regulator_enable(st->reg_vss);
        if (ret)
            goto error_put_reg_neg;

        neg_voltage_uv = regulator_get_voltage(st->reg_vss);
    }

    st->pwr_down = true;
    st->spi = spi;

    if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
        st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
        st->vref_neg_mv = neg_voltage_uv / 1000;
    } else if (pdata) {
        st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
        st->vref_neg_mv = pdata->vref_neg_mv;
    } else {
        dev_warn(&spi->dev, "reference voltage unspecified\n");
    }

    ret = ad5791_spi_write(spi, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
    if (ret)
        goto error_disable_reg_neg;

    st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
                          ->driver_data];


    st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
          | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
          AD5791_CTRL_BIN2SC;

    ret = ad5791_spi_write(spi, AD5791_ADDR_CTRL, st->ctrl |
        AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
    if (ret)
        goto error_disable_reg_neg;

    spi_set_drvdata(spi, indio_dev);
    indio_dev->dev.parent = &spi->dev;
    indio_dev->info = &ad5791_info;
    indio_dev->modes = INDIO_DIRECT_MODE;
    indio_dev->channels
        = &ad5791_channels[spi_get_device_id(spi)->driver_data];
    indio_dev->num_channels = 1;
    indio_dev->name = spi_get_device_id(st->spi)->name;
    ret = iio_device_register(indio_dev);
    if (ret)
        goto error_disable_reg_neg;

    return 0;

error_disable_reg_neg:
    if (!IS_ERR(st->reg_vss))
        regulator_disable(st->reg_vss);
error_put_reg_neg:
    if (!IS_ERR(st->reg_vss))
        regulator_put(st->reg_vss);

    if (!IS_ERR(st->reg_vdd))
        regulator_disable(st->reg_vdd);
error_put_reg_pos:
    if (!IS_ERR(st->reg_vdd))
        regulator_put(st->reg_vdd);
    iio_device_free(indio_dev);
error_ret:

    return ret;
}

static int __devexit ad5791_remove(struct spi_device *spi)
{
    struct iio_dev *indio_dev = spi_get_drvdata(spi);
    struct ad5791_state *st = iio_priv(indio_dev);

    iio_device_unregister(indio_dev);
    if (!IS_ERR(st->reg_vdd)) {
        regulator_disable(st->reg_vdd);
        regulator_put(st->reg_vdd);
    }

    if (!IS_ERR(st->reg_vss)) {
        regulator_disable(st->reg_vss);
        regulator_put(st->reg_vss);
    }
    iio_device_free(indio_dev);

    return 0;
}

static const struct spi_device_id ad5791_id[] = {
    {"ad5760", ID_AD5760},
    {"ad5780", ID_AD5780},
    {"ad5781", ID_AD5781},
    {"ad5790", ID_AD5791},
    {"ad5791", ID_AD5791},
    {}
};
MODULE_DEVICE_TABLE(spi, ad5791_id);

static struct spi_driver ad5791_driver = {
    .driver = {
           .name = "ad5791",
           .owner = THIS_MODULE,
           },
    .probe = ad5791_probe,
    .remove = __devexit_p(ad5791_remove),
    .id_table = ad5791_id,
};
module_spi_driver(ad5791_driver);

MODULE_AUTHOR("Michael Hennerich <[email protected]>");
MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
MODULE_LICENSE("GPL v2");