ad5064.c

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/*
 * 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_DAC(chan)           (chan)
#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 {
    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 {
    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,
    unsigned int channel)
{
    unsigned int val;
    int ret;

    val = (0x1 << channel);

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

        scale_uv = (scale_uv * 100) >> chan->scan_type.realbits;
        *val =  scale_uv / 100000;
        *val2 = (scale_uv % 100000) * 10;
        return IIO_VAL_INT_PLUS_MICRO;
    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,
    },
    IIO_ENUM("powerdown_mode", false, &ad5064_powerdown_mode_enum),
    IIO_ENUM_AVAILABLE("powerdown_mode", &ad5064_powerdown_mode_enum),
    { },
};

#define AD5064_CHANNEL(chan, bits) {                \
    .type = IIO_VOLTAGE,                    \
    .indexed = 1,                       \
    .output = 1,                        \
    .channel = (chan),                  \
    .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |       \
    IIO_CHAN_INFO_SCALE_SEPARATE_BIT,           \
    .address = AD5064_ADDR_DAC(chan),           \
    .scan_type = IIO_ST('u', (bits), 16, 20 - (bits)),  \
    .ext_info = ad5064_ext_info,                \
}

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

static DECLARE_AD5064_CHANNELS(ad5024_channels, 12);
static DECLARE_AD5064_CHANNELS(ad5044_channels, 14);
static DECLARE_AD5064_CHANNELS(ad5064_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 = ad5024_channels,
        .num_channels = 2,
    },
    [ID_AD5044] = {
        .shared_vref = false,
        .channels = ad5044_channels,
        .num_channels = 4,
    },
    [ID_AD5045] = {
        .shared_vref = false,
        .channels = ad5044_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 = ad5064_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 __devinit 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 i;
    int ret;

    indio_dev = iio_device_alloc(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 = regulator_bulk_get(dev, ad5064_num_vref(st),
        st->vref_reg);
    if (ret) {
        if (!st->chip_info->internal_vref)
            goto error_free;
        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);
            goto error_free;
        }
    } else {
        ret = regulator_bulk_enable(ad5064_num_vref(st), st->vref_reg);
        if (ret)
            goto error_free_reg;
    }

    for (i = 0; i < st->chip_info->num_channels; ++i) {
        st->pwr_down_mode[i] = AD5064_LDAC_PWRDN_1K;
        st->dac_cache[i] = 0x8000;
    }

    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;

    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);
error_free_reg:
    if (!st->use_internal_vref)
        regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
error_free:
    iio_device_free(indio_dev);

    return ret;
}

static int __devexit 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);
        regulator_bulk_free(ad5064_num_vref(st), st->vref_reg);
    }

    iio_device_free(indio_dev);

    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 __devinit 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 __devexit 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 = __devexit_p(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 __devinit 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 __devexit 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 = __devexit_p(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 <[email protected]>");
MODULE_DESCRIPTION("Analog Devices AD5024 and similar multi-channel DACs");
MODULE_LICENSE("GPL v2");