adxl34x-spi.c

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/*
 * ADLX345/346 Three-Axis Digital Accelerometers (SPI Interface)
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Copyright (C) 2009 Michael Hennerich, Analog Devices Inc.
 * Licensed under the GPL-2 or later.
 */

#include <linux/input.h>    /* BUS_SPI */
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/pm.h>
#include <linux/types.h>
#include "adxl34x.h"

#define MAX_SPI_FREQ_HZ     5000000
#define MAX_FREQ_NO_FIFODELAY   1500000
#define ADXL34X_CMD_MULTB   (1 << 6)
#define ADXL34X_CMD_READ    (1 << 7)
#define ADXL34X_WRITECMD(reg)   (reg & 0x3F)
#define ADXL34X_READCMD(reg)    (ADXL34X_CMD_READ | (reg & 0x3F))
#define ADXL34X_READMB_CMD(reg) (ADXL34X_CMD_READ | ADXL34X_CMD_MULTB \
                    | (reg & 0x3F))

static int adxl34x_spi_read(struct device *dev, unsigned char reg)
{
    struct spi_device *spi = to_spi_device(dev);
    unsigned char cmd;

    cmd = ADXL34X_READCMD(reg);

    return spi_w8r8(spi, cmd);
}

static int adxl34x_spi_write(struct device *dev,
                 unsigned char reg, unsigned char val)
{
    struct spi_device *spi = to_spi_device(dev);
    unsigned char buf[2];

    buf[0] = ADXL34X_WRITECMD(reg);
    buf[1] = val;

    return spi_write(spi, buf, sizeof(buf));
}

static int adxl34x_spi_read_block(struct device *dev,
                  unsigned char reg, int count,
                  void *buf)
{
    struct spi_device *spi = to_spi_device(dev);
    ssize_t status;

    reg = ADXL34X_READMB_CMD(reg);
    status = spi_write_then_read(spi, &reg, 1, buf, count);

    return (status < 0) ? status : 0;
}

static const struct adxl34x_bus_ops adxl34x_spi_bops = {
    .bustype    = BUS_SPI,
    .write      = adxl34x_spi_write,
    .read       = adxl34x_spi_read,
    .read_block = adxl34x_spi_read_block,
};

static int __devinit adxl34x_spi_probe(struct spi_device *spi)
{
    struct adxl34x *ac;

    /* don't exceed max specified SPI CLK frequency */
    if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
        dev_err(&spi->dev, "SPI CLK %d Hz too fast\n", spi->max_speed_hz);
        return -EINVAL;
    }

    ac = adxl34x_probe(&spi->dev, spi->irq,
               spi->max_speed_hz > MAX_FREQ_NO_FIFODELAY,
               &adxl34x_spi_bops);

    if (IS_ERR(ac))
        return PTR_ERR(ac);

    spi_set_drvdata(spi, ac);

    return 0;
}

static int __devexit adxl34x_spi_remove(struct spi_device *spi)
{
    struct adxl34x *ac = dev_get_drvdata(&spi->dev);

    return adxl34x_remove(ac);
}

#ifdef CONFIG_PM
static int adxl34x_spi_suspend(struct device *dev)
{
    struct spi_device *spi = to_spi_device(dev);
    struct adxl34x *ac = dev_get_drvdata(&spi->dev);

    adxl34x_suspend(ac);

    return 0;
}

static int adxl34x_spi_resume(struct device *dev)
{
    struct spi_device *spi = to_spi_device(dev);
    struct adxl34x *ac = dev_get_drvdata(&spi->dev);

    adxl34x_resume(ac);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(adxl34x_spi_pm, adxl34x_spi_suspend,
             adxl34x_spi_resume);

static struct spi_driver adxl34x_driver = {
    .driver = {
        .name = "adxl34x",
        .owner = THIS_MODULE,
        .pm = &adxl34x_spi_pm,
    },
    .probe   = adxl34x_spi_probe,
    .remove  = __devexit_p(adxl34x_spi_remove),
};

module_spi_driver(adxl34x_driver);

MODULE_AUTHOR("Michael Hennerich <[email protected]>");
MODULE_DESCRIPTION("ADXL345/346 Three-Axis Digital Accelerometer SPI Bus Driver");
MODULE_LICENSE("GPL");