edb93xx.c

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/*
 * SoC audio for EDB93xx
 *
 * Copyright (c) 2010 Alexander Sverdlin <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * This driver support CS4271 codec being master or slave, working
 * in control port mode, connected either via SPI or I2C.
 * The data format accepted is I2S or left-justified.
 * DAPM support not implemented.
 */

#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/soc.h>
#include <asm/mach-types.h>
#include <mach/hardware.h>
#include "ep93xx-pcm.h"

static int edb93xx_hw_params(struct snd_pcm_substream *substream,
                 struct snd_pcm_hw_params *params)
{
    struct snd_soc_pcm_runtime *rtd = substream->private_data;
    struct snd_soc_dai *codec_dai = rtd->codec_dai;
    struct snd_soc_dai *cpu_dai = rtd->cpu_dai;
    int err;
    unsigned int mclk_rate;
    unsigned int rate = params_rate(params);

    /*
     * According to CS4271 datasheet we use MCLK/LRCK=256 for
     * rates below 50kHz and 128 for higher sample rates
     */
    if (rate < 50000)
        mclk_rate = rate * 64 * 4;
    else
        mclk_rate = rate * 64 * 2;

    err = snd_soc_dai_set_sysclk(codec_dai, 0, mclk_rate,
                     SND_SOC_CLOCK_IN);
    if (err)
        return err;

    return snd_soc_dai_set_sysclk(cpu_dai, 0, mclk_rate,
                      SND_SOC_CLOCK_OUT);
}

static struct snd_soc_ops edb93xx_ops = {
    .hw_params  = edb93xx_hw_params,
};

static struct snd_soc_dai_link edb93xx_dai = {
    .name       = "CS4271",
    .stream_name    = "CS4271 HiFi",
    .platform_name  = "ep93xx-pcm-audio",
    .cpu_dai_name   = "ep93xx-i2s",
    .codec_name = "spi0.0",
    .codec_dai_name = "cs4271-hifi",
    .dai_fmt    = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_IF |
              SND_SOC_DAIFMT_CBS_CFS,
    .ops        = &edb93xx_ops,
};

static struct snd_soc_card snd_soc_edb93xx = {
    .name       = "EDB93XX",
    .owner      = THIS_MODULE,
    .dai_link   = &edb93xx_dai,
    .num_links  = 1,
};

static int __devinit edb93xx_probe(struct platform_device *pdev)
{
    struct snd_soc_card *card = &snd_soc_edb93xx;
    int ret;

    ret = ep93xx_i2s_acquire();
    if (ret)
        return ret;

    card->dev = &pdev->dev;

    ret = snd_soc_register_card(card);
    if (ret) {
        dev_err(&pdev->dev, "snd_soc_register_card() failed: %d\n",
            ret);
        ep93xx_i2s_release();
    }

    return ret;
}

static int __devexit edb93xx_remove(struct platform_device *pdev)
{
    struct snd_soc_card *card = platform_get_drvdata(pdev);

    snd_soc_unregister_card(card);
    ep93xx_i2s_release();

    return 0;
}

static struct platform_driver edb93xx_driver = {
    .driver     = {
        .name   = "edb93xx-audio",
        .owner  = THIS_MODULE,
    },
    .probe      = edb93xx_probe,
    .remove     = __devexit_p(edb93xx_remove),
};

module_platform_driver(edb93xx_driver);

MODULE_AUTHOR("Alexander Sverdlin <[email protected]>");
MODULE_DESCRIPTION("ALSA SoC EDB93xx");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:edb93xx-audio");