linux-imx

/*

 * Copyright (C) 2006 Juergen Beisert, Pengutronix

 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix

 * Copyright (C) 2009 Wolfram Sang, Pengutronix

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * Check max730x.c for further details.

 */

​

#include <linux/module.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>

#include <linux/spi/max7301.h>

​

/* A write to the MAX7301 means one message with one transfer */

static int max7301_spi_write(struct device *dev, unsigned int reg,

                unsigned int val)

{

    struct spi_device *spi = to_spi_device(dev);

    u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);

​

    return spi_write_then_read(spi, &word, sizeof(word), NULL, 0);

}

​

/* A read from the MAX7301 means two transfers; here, one message each */

​

static int max7301_spi_read(struct device *dev, unsigned int reg)

{

    int ret;

    u16 word;

    struct spi_device *spi = to_spi_device(dev);

​

    word = 0x8000 | (reg << 8);

    ret = spi_write_then_read(spi, &word, sizeof(word), &word,

                  sizeof(word));

    if (ret)

        return ret;

    return word & 0xff;

}

​

static int max7301_probe(struct spi_device *spi)

{

    struct max7301 *ts;

    int ret;

​

    /* bits_per_word cannot be configured in platform data */

    spi->bits_per_word = 16;

    ret = spi_setup(spi);

    if (ret < 0)

        return ret;

​

    ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL);

    if (!ts)

        return -ENOMEM;

​

    ts->read = max7301_spi_read;

    ts->write = max7301_spi_write;