adis16060_core.c

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/*
 * ADIS16060 Wide Bandwidth Yaw Rate Gyroscope with SPI driver
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

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

#define ADIS16060_GYRO      0x20 /* Measure Angular Rate (Gyro) */
#define ADIS16060_TEMP_OUT  0x10 /* Measure Temperature */
#define ADIS16060_AIN2      0x80 /* Measure AIN2 */
#define ADIS16060_AIN1      0x40 /* Measure AIN1 */

struct adis16060_state {
    struct spi_device       *us_w;
    struct spi_device       *us_r;
    struct mutex            buf_lock;

    u8 buf[3] ____cacheline_aligned;
};

static struct iio_dev *adis16060_iio_dev;

static int adis16060_spi_write(struct iio_dev *indio_dev, u8 val)
{
    int ret;
    struct adis16060_state *st = iio_priv(indio_dev);

    mutex_lock(&st->buf_lock);
    st->buf[2] = val; /* The last 8 bits clocked in are latched */
    ret = spi_write(st->us_w, st->buf, 3);
    mutex_unlock(&st->buf_lock);

    return ret;
}

static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val)
{
    int ret;
    struct adis16060_state *st = iio_priv(indio_dev);

    mutex_lock(&st->buf_lock);

    ret = spi_read(st->us_r, st->buf, 3);

    /* The internal successive approximation ADC begins the
     * conversion process on the falling edge of MSEL1 and
     * starts to place data MSB first on the DOUT line at
     * the 6th falling edge of SCLK
     */
    if (ret == 0)
        *val = ((st->buf[0] & 0x3) << 12) |
            (st->buf[1] << 4) |
            ((st->buf[2] >> 4) & 0xF);
    mutex_unlock(&st->buf_lock);

    return ret;
}

static int adis16060_read_raw(struct iio_dev *indio_dev,
                  struct iio_chan_spec const *chan,
                  int *val, int *val2,
                  long mask)
{
    u16 tval = 0;
    int ret;

    switch (mask) {
    case IIO_CHAN_INFO_RAW:
        /* Take the iio_dev status lock */
        mutex_lock(&indio_dev->mlock);
        ret = adis16060_spi_write(indio_dev, chan->address);
        if (ret < 0) {
            mutex_unlock(&indio_dev->mlock);
            return ret;
        }
        ret = adis16060_spi_read(indio_dev, &tval);
        mutex_unlock(&indio_dev->mlock);
        *val = tval;
        return IIO_VAL_INT;
    case IIO_CHAN_INFO_OFFSET:
        *val = -7;
        *val2 = 461117;
        return IIO_VAL_INT_PLUS_MICRO;
    case IIO_CHAN_INFO_SCALE:
        *val = 0;
        *val2 = 34000;
        return IIO_VAL_INT_PLUS_MICRO;
    }

    return -EINVAL;
}

static const struct iio_info adis16060_info = {
    .read_raw = &adis16060_read_raw,
    .driver_module = THIS_MODULE,
};

static const struct iio_chan_spec adis16060_channels[] = {
    {
        .type = IIO_ANGL_VEL,
        .modified = 1,
        .channel2 = IIO_MOD_Z,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16060_GYRO,
    }, {
        .type = IIO_VOLTAGE,
        .indexed = 1,
        .channel = 0,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16060_AIN1,
    }, {
        .type = IIO_VOLTAGE,
        .indexed = 1,
        .channel = 1,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16060_AIN2,
    }, {
        .type = IIO_TEMP,
        .indexed = 1,
        .channel = 0,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
        IIO_CHAN_INFO_OFFSET_SEPARATE_BIT |
        IIO_CHAN_INFO_SCALE_SEPARATE_BIT,
        .address = ADIS16060_TEMP_OUT,
    }
};

static int __devinit adis16060_r_probe(struct spi_device *spi)
{
    int ret;
    struct adis16060_state *st;
    struct iio_dev *indio_dev;

    /* setup the industrialio driver allocated elements */
    indio_dev = iio_device_alloc(sizeof(*st));
    if (indio_dev == NULL) {
        ret = -ENOMEM;
        goto error_ret;
    }
    /* this is only used for removal purposes */
    spi_set_drvdata(spi, indio_dev);
    st = iio_priv(indio_dev);
    st->us_r = spi;
    mutex_init(&st->buf_lock);

    indio_dev->name = spi->dev.driver->name;
    indio_dev->dev.parent = &spi->dev;
    indio_dev->info = &adis16060_info;
    indio_dev->modes = INDIO_DIRECT_MODE;
    indio_dev->channels = adis16060_channels;
    indio_dev->num_channels = ARRAY_SIZE(adis16060_channels);

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

    adis16060_iio_dev = indio_dev;
    return 0;

error_free_dev:
    iio_device_free(indio_dev);
error_ret:
    return ret;
}

/* fixme, confirm ordering in this function */
static int __devexit adis16060_r_remove(struct spi_device *spi)
{
    iio_device_unregister(spi_get_drvdata(spi));
    iio_device_free(spi_get_drvdata(spi));

    return 0;
}

static int __devinit adis16060_w_probe(struct spi_device *spi)
{
    int ret;
    struct iio_dev *indio_dev = adis16060_iio_dev;
    struct adis16060_state *st;
    if (!indio_dev) {
        ret =  -ENODEV;
        goto error_ret;
    }
    st = iio_priv(indio_dev);
    spi_set_drvdata(spi, indio_dev);
    st->us_w = spi;
    return 0;

error_ret:
    return ret;
}

static int __devexit adis16060_w_remove(struct spi_device *spi)
{
    return 0;
}

static struct spi_driver adis16060_r_driver = {
    .driver = {
        .name = "adis16060_r",
        .owner = THIS_MODULE,
    },
    .probe = adis16060_r_probe,
    .remove = __devexit_p(adis16060_r_remove),
};

static struct spi_driver adis16060_w_driver = {
    .driver = {
        .name = "adis16060_w",
        .owner = THIS_MODULE,
    },
    .probe = adis16060_w_probe,
    .remove = __devexit_p(adis16060_w_remove),
};

static __init int adis16060_init(void)
{
    int ret;

    ret = spi_register_driver(&adis16060_r_driver);
    if (ret < 0)
        return ret;

    ret = spi_register_driver(&adis16060_w_driver);
    if (ret < 0) {
        spi_unregister_driver(&adis16060_r_driver);
        return ret;
    }

    return 0;
}
module_init(adis16060_init);

static __exit void adis16060_exit(void)
{
    spi_unregister_driver(&adis16060_w_driver);
    spi_unregister_driver(&adis16060_r_driver);
}
module_exit(adis16060_exit);

MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("Analog Devices ADIS16060 Yaw Rate Gyroscope Driver");
MODULE_LICENSE("GPL v2");