adis16130_core.c

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/*
 * ADIS16130 Digital Output, High Precision Angular Rate Sensor 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/list.h>
#include <linux/module.h>

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

#define ADIS16130_CON         0x0
#define ADIS16130_CON_RD      (1 << 6)
#define ADIS16130_IOP         0x1

/* 1 = data-ready signal low when unread data on all channels; */
#define ADIS16130_IOP_ALL_RDY (1 << 3)
#define ADIS16130_IOP_SYNC    (1 << 0) /* 1 = synchronization enabled */
#define ADIS16130_RATEDATA    0x8 /* Gyroscope output, rate of rotation */
#define ADIS16130_TEMPDATA    0xA /* Temperature output */
#define ADIS16130_RATECS      0x28 /* Gyroscope channel setup */
#define ADIS16130_RATECS_EN   (1 << 3) /* 1 = channel enable; */
#define ADIS16130_TEMPCS      0x2A /* Temperature channel setup */
#define ADIS16130_TEMPCS_EN   (1 << 3)
#define ADIS16130_RATECONV    0x30
#define ADIS16130_TEMPCONV    0x32
#define ADIS16130_MODE        0x38
#define ADIS16130_MODE_24BIT  (1 << 1) /* 1 = 24-bit resolution; */

struct adis16130_state {
    struct spi_device       *us;
    struct mutex            buf_lock;
    u8              buf[4] ____cacheline_aligned;
};

static int adis16130_spi_read(struct iio_dev *indio_dev, u8 reg_addr, u32 *val)
{
    int ret;
    struct adis16130_state *st = iio_priv(indio_dev);
    struct spi_message msg;
    struct spi_transfer xfer = {
        .tx_buf = st->buf,
        .rx_buf = st->buf,
        .len = 4,
    };

    mutex_lock(&st->buf_lock);

    st->buf[0] = ADIS16130_CON_RD | reg_addr;
    st->buf[1] = st->buf[2] = st->buf[3] = 0;

    spi_message_init(&msg);
    spi_message_add_tail(&xfer, &msg);
    ret = spi_sync(st->us, &msg);
    ret = spi_read(st->us, st->buf, 4);

    if (ret == 0)
        *val = (st->buf[1] << 16) | (st->buf[2] << 8) | st->buf[3];
    mutex_unlock(&st->buf_lock);

    return ret;
}

static int adis16130_read_raw(struct iio_dev *indio_dev,
                  struct iio_chan_spec const *chan,
                  int *val, int *val2,
                  long mask)
{
    int ret;
    u32 temp;

    /* Take the iio_dev status lock */
    mutex_lock(&indio_dev->mlock);
    ret =  adis16130_spi_read(indio_dev, chan->address, &temp);
    mutex_unlock(&indio_dev->mlock);
    if (ret)
        return ret;
    *val = temp;
    return IIO_VAL_INT;
}

static const struct iio_chan_spec adis16130_channels[] = {
    {
        .type = IIO_ANGL_VEL,
        .modified = 1,
        .channel2 = IIO_MOD_Z,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16130_RATEDATA,
    }, {
        .type = IIO_TEMP,
        .indexed = 1,
        .channel = 0,
        .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT,
        .address = ADIS16130_TEMPDATA,
    }
};

static const struct iio_info adis16130_info = {
    .read_raw = &adis16130_read_raw,
    .driver_module = THIS_MODULE,
};

static int __devinit adis16130_probe(struct spi_device *spi)
{
    int ret;
    struct adis16130_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);
    st->us = spi;
    mutex_init(&st->buf_lock);
    indio_dev->name = spi->dev.driver->name;
    indio_dev->channels = adis16130_channels;
    indio_dev->num_channels = ARRAY_SIZE(adis16130_channels);
    indio_dev->dev.parent = &spi->dev;
    indio_dev->info = &adis16130_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 adis16130_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 adis16130_driver = {
    .driver = {
        .name = "adis16130",
        .owner = THIS_MODULE,
    },
    .probe = adis16130_probe,
    .remove = __devexit_p(adis16130_remove),
};
module_spi_driver(adis16130_driver);

MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("Analog Devices ADIS16130 High Precision Angular Rate");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:adis16130");