adis16080_core.c

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/*
 * ADIS16080/100 Yaw Rate Gyroscope with SPI driver
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */
#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/module.h>

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

#define ADIS16080_DIN_GYRO   (0 << 10) /* Gyroscope output */
#define ADIS16080_DIN_TEMP   (1 << 10) /* Temperature output */
#define ADIS16080_DIN_AIN1   (2 << 10)
#define ADIS16080_DIN_AIN2   (3 << 10)

/*
 * 1: Write contents on DIN to control register.
 * 0: No changes to control register.
 */

#define ADIS16080_DIN_WRITE  (1 << 15)

struct adis16080_state {
    struct spi_device       *us;
    struct mutex            buf_lock;

    u8 buf[2] ____cacheline_aligned;
};

static int adis16080_spi_write(struct iio_dev *indio_dev,
        u16 val)
{
    int ret;
    struct adis16080_state *st = iio_priv(indio_dev);

    mutex_lock(&st->buf_lock);
    st->buf[0] = val >> 8;
    st->buf[1] = val;

    ret = spi_write(st->us, st->buf, 2);
    mutex_unlock(&st->buf_lock);

    return ret;
}

static int adis16080_spi_read(struct iio_dev *indio_dev,
                  u16 *val)
{
    int ret;
    struct adis16080_state *st = iio_priv(indio_dev);

    mutex_lock(&st->buf_lock);

    ret = spi_read(st->us, st->buf, 2);

    if (ret == 0)
        *val = ((st->buf[0] & 0xF) << 8) | st->buf[1];
    mutex_unlock(&st->buf_lock);

    return ret;
}

static int adis16080_read_raw(struct iio_dev *indio_dev,
                 struct iio_chan_spec const *chan,
                 int *val,
                 int *val2,
                 long mask)
{
    int ret = -EINVAL;
    u16 ut = 0;
    /* Take the iio_dev status lock */

    mutex_lock(&indio_dev->mlock);
    switch (mask) {
    case IIO_CHAN_INFO_RAW:
        ret = adis16080_spi_write(indio_dev,
                      chan->address |
                      ADIS16080_DIN_WRITE);
        if (ret < 0)
            break;
        ret = adis16080_spi_read(indio_dev, &ut);
        if (ret < 0)
            break;
        *val = ut;
        ret = IIO_VAL_INT;
        break;
    }
    mutex_unlock(&indio_dev->mlock);

    return ret;
}

static const struct iio_chan_spec adis16080_channels[] = {
    {
        .type = IIO_ANGL_VEL,
        .modified = 1,
        .channel2 = IIO_MOD_Z,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16080_DIN_GYRO,
    }, {
        .type = IIO_VOLTAGE,
        .indexed = 1,
        .channel = 0,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16080_DIN_AIN1,
    }, {
        .type = IIO_VOLTAGE,
        .indexed = 1,
        .channel = 1,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16080_DIN_AIN2,
    }, {
        .type = IIO_TEMP,
        .indexed = 1,
        .channel = 0,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16080_DIN_TEMP,
    }
};

static const struct iio_info adis16080_info = {
    .read_raw = &adis16080_read_raw,
    .driver_module = THIS_MODULE,
};

static int __devinit adis16080_probe(struct spi_device *spi)
{
    int ret;
    struct adis16080_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;
    }
    st = iio_priv(indio_dev);
    /* this is only used for removal purposes */
    spi_set_drvdata(spi, indio_dev);

    /* Allocate the comms buffers */
    st->us = spi;
    mutex_init(&st->buf_lock);

    indio_dev->name = spi->dev.driver->name;
    indio_dev->channels = adis16080_channels;
    indio_dev->num_channels = ARRAY_SIZE(adis16080_channels);
    indio_dev->dev.parent = &spi->dev;
    indio_dev->info = &adis16080_info;
    indio_dev->modes = INDIO_DIRECT_MODE;

    ret = iio_device_register(indio_dev);
    if (ret)
        goto error_free_dev;
    return 0;

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

/* fixme, confirm ordering in this function */
static int __devexit adis16080_remove(struct spi_device *spi)
{
    iio_device_unregister(spi_get_drvdata(spi));
    iio_device_free(spi_get_drvdata(spi));

    return 0;
}

static struct spi_driver adis16080_driver = {
    .driver = {
        .name = "adis16080",
        .owner = THIS_MODULE,
    },
    .probe = adis16080_probe,
    .remove = __devexit_p(adis16080_remove),
};
module_spi_driver(adis16080_driver);

MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("Analog Devices ADIS16080/100 Yaw Rate Gyroscope Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:adis16080");