ad5624r_spi.c

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/*
 * AD5624R, AD5644R, AD5664R Digital to analog convertors spi driver
 *
 * Copyright 2010-2011 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 "ad5624r.h"

static int ad5624r_spi_write(struct spi_device *spi,
                 u8 cmd, u8 addr, u16 val, u8 len)
{
    u32 data;
    u8 msg[3];

    /*
     * The input shift register is 24 bits wide. The first two bits are
     * don't care bits. The next three are the command bits, C2 to C0,
     * followed by the 3-bit DAC address, A2 to A0, and then the
     * 16-, 14-, 12-bit data-word. The data-word comprises the 16-,
     * 14-, 12-bit input code followed by 0, 2, or 4 don't care bits,
     * for the AD5664R, AD5644R, and AD5624R, respectively.
     */
    data = (0 << 22) | (cmd << 19) | (addr << 16) | (val << (16 - len));
    msg[0] = data >> 16;
    msg[1] = data >> 8;
    msg[2] = data;

    return spi_write(spi, msg, 3);
}

static int ad5624r_read_raw(struct iio_dev *indio_dev,
               struct iio_chan_spec const *chan,
               int *val,
               int *val2,
               long m)
{
    struct ad5624r_state *st = iio_priv(indio_dev);
    unsigned long scale_uv;

    switch (m) {
    case IIO_CHAN_INFO_SCALE:
        scale_uv = (st->vref_mv * 1000) >> chan->scan_type.realbits;
        *val =  scale_uv / 1000;
        *val2 = (scale_uv % 1000) * 1000;
        return IIO_VAL_INT_PLUS_MICRO;

    }
    return -EINVAL;
}

static int ad5624r_write_raw(struct iio_dev *indio_dev,
                   struct iio_chan_spec const *chan,
                   int val,
                   int val2,
                   long mask)
{
    struct ad5624r_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;

        return ad5624r_spi_write(st->us,
                AD5624R_CMD_WRITE_INPUT_N_UPDATE_N,
                chan->address, val,
                chan->scan_type.shift);
    default:
        ret = -EINVAL;
    }

    return -EINVAL;
}

static const char * const ad5624r_powerdown_modes[] = {
    "1kohm_to_gnd",
    "100kohm_to_gnd",
    "three_state"
};

static int ad5624r_get_powerdown_mode(struct iio_dev *indio_dev,
    const struct iio_chan_spec *chan)
{
    struct ad5624r_state *st = iio_priv(indio_dev);

    return st->pwr_down_mode;
}

static int ad5624r_set_powerdown_mode(struct iio_dev *indio_dev,
    const struct iio_chan_spec *chan, unsigned int mode)
{
    struct ad5624r_state *st = iio_priv(indio_dev);

    st->pwr_down_mode = mode;

    return 0;
}

static const struct iio_enum ad5624r_powerdown_mode_enum = {
    .items = ad5624r_powerdown_modes,
    .num_items = ARRAY_SIZE(ad5624r_powerdown_modes),
    .get = ad5624r_get_powerdown_mode,
    .set = ad5624r_set_powerdown_mode,
};

static ssize_t ad5624r_read_dac_powerdown(struct iio_dev *indio_dev,
    uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
    struct ad5624r_state *st = iio_priv(indio_dev);

    return sprintf(buf, "%d\n",
            !!(st->pwr_down_mask & (1 << chan->channel)));
}

static ssize_t ad5624r_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 ad5624r_state *st = iio_priv(indio_dev);

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

    if (pwr_down)
        st->pwr_down_mask |= (1 << chan->channel);
    else
        st->pwr_down_mask &= ~(1 << chan->channel);

    ret = ad5624r_spi_write(st->us, AD5624R_CMD_POWERDOWN_DAC, 0,
                (st->pwr_down_mode << 4) |
                st->pwr_down_mask, 16);

    return ret ? ret : len;
}

static const struct iio_info ad5624r_info = {
    .write_raw = ad5624r_write_raw,
    .read_raw = ad5624r_read_raw,
    .driver_module = THIS_MODULE,
};

static const struct iio_chan_spec_ext_info ad5624r_ext_info[] = {
    {
        .name = "powerdown",
        .read = ad5624r_read_dac_powerdown,
        .write = ad5624r_write_dac_powerdown,
    },
    IIO_ENUM("powerdown_mode", true, &ad5624r_powerdown_mode_enum),
    IIO_ENUM_AVAILABLE("powerdown_mode", &ad5624r_powerdown_mode_enum),
    { },
};

#define AD5624R_CHANNEL(_chan, _bits) { \
    .type = IIO_VOLTAGE, \
    .indexed = 1, \
    .output = 1, \
    .channel = (_chan), \
    .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
             IIO_CHAN_INFO_SCALE_SHARED_BIT, \
    .address = (_chan), \
    .scan_type = IIO_ST('u', (_bits), 16, 16 - (_bits)), \
    .ext_info = ad5624r_ext_info, \
}

#define DECLARE_AD5624R_CHANNELS(_name, _bits) \
    const struct iio_chan_spec _name##_channels[] = { \
        AD5624R_CHANNEL(0, _bits), \
        AD5624R_CHANNEL(1, _bits), \
        AD5624R_CHANNEL(2, _bits), \
        AD5624R_CHANNEL(3, _bits), \
}

static DECLARE_AD5624R_CHANNELS(ad5624r, 12);
static DECLARE_AD5624R_CHANNELS(ad5644r, 14);
static DECLARE_AD5624R_CHANNELS(ad5664r, 16);

static const struct ad5624r_chip_info ad5624r_chip_info_tbl[] = {
    [ID_AD5624R3] = {
        .channels = ad5624r_channels,
        .int_vref_mv = 1250,
    },
    [ID_AD5624R5] = {
        .channels = ad5624r_channels,
        .int_vref_mv = 2500,
    },
    [ID_AD5644R3] = {
        .channels = ad5644r_channels,
        .int_vref_mv = 1250,
    },
    [ID_AD5644R5] = {
        .channels = ad5644r_channels,
        .int_vref_mv = 2500,
    },
    [ID_AD5664R3] = {
        .channels = ad5664r_channels,
        .int_vref_mv = 1250,
    },
    [ID_AD5664R5] = {
        .channels = ad5664r_channels,
        .int_vref_mv = 2500,
    },
};

static int __devinit ad5624r_probe(struct spi_device *spi)
{
    struct ad5624r_state *st;
    struct iio_dev *indio_dev;
    int ret, 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 = regulator_get(&spi->dev, "vcc");
    if (!IS_ERR(st->reg)) {
        ret = regulator_enable(st->reg);
        if (ret)
            goto error_put_reg;

        voltage_uv = regulator_get_voltage(st->reg);
    }

    spi_set_drvdata(spi, indio_dev);
    st->chip_info =
        &ad5624r_chip_info_tbl[spi_get_device_id(spi)->driver_data];

    if (voltage_uv)
        st->vref_mv = voltage_uv / 1000;
    else
        st->vref_mv = st->chip_info->int_vref_mv;

    st->us = spi;

    indio_dev->dev.parent = &spi->dev;
    indio_dev->name = spi_get_device_id(spi)->name;
    indio_dev->info = &ad5624r_info;
    indio_dev->modes = INDIO_DIRECT_MODE;
    indio_dev->channels = st->chip_info->channels;
    indio_dev->num_channels = AD5624R_DAC_CHANNELS;

    ret = ad5624r_spi_write(spi, AD5624R_CMD_INTERNAL_REFER_SETUP, 0,
                !!voltage_uv, 16);
    if (ret)
        goto error_disable_reg;

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

    return 0;

error_disable_reg:
    if (!IS_ERR(st->reg))
        regulator_disable(st->reg);
error_put_reg:
    if (!IS_ERR(st->reg))
        regulator_put(st->reg);
    iio_device_free(indio_dev);
error_ret:

    return ret;
}

static int __devexit ad5624r_remove(struct spi_device *spi)
{
    struct iio_dev *indio_dev = spi_get_drvdata(spi);
    struct ad5624r_state *st = iio_priv(indio_dev);

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

    return 0;
}

static const struct spi_device_id ad5624r_id[] = {
    {"ad5624r3", ID_AD5624R3},
    {"ad5644r3", ID_AD5644R3},
    {"ad5664r3", ID_AD5664R3},
    {"ad5624r5", ID_AD5624R5},
    {"ad5644r5", ID_AD5644R5},
    {"ad5664r5", ID_AD5664R5},
    {}
};
MODULE_DEVICE_TABLE(spi, ad5624r_id);

static struct spi_driver ad5624r_driver = {
    .driver = {
           .name = "ad5624r",
           .owner = THIS_MODULE,
           },
    .probe = ad5624r_probe,
    .remove = __devexit_p(ad5624r_remove),
    .id_table = ad5624r_id,
};
module_spi_driver(ad5624r_driver);

MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("Analog Devices AD5624/44/64R DAC spi driver");
MODULE_LICENSE("GPL v2");