smdk_spdif.c

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/*
 * smdk_spdif.c  --  S/PDIF audio for SMDK
 *
 * Copyright 2010 Samsung Electronics Co. Ltd.
 *
 * 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.
 *
 */

#include <linux/clk.h>
#include <linux/module.h>

#include <sound/soc.h>

#include "spdif.h"

/* Audio clock settings are belonged to board specific part. Every
 * board can set audio source clock setting which is matched with H/W
 * like this function-'set_audio_clock_heirachy'.
 */
static int set_audio_clock_heirachy(struct platform_device *pdev)
{
    struct clk *fout_epll, *mout_epll, *sclk_audio0, *sclk_spdif;
    int ret = 0;

    fout_epll = clk_get(NULL, "fout_epll");
    if (IS_ERR(fout_epll)) {
        printk(KERN_WARNING "%s: Cannot find fout_epll.\n",
                __func__);
        return -EINVAL;
    }

    mout_epll = clk_get(NULL, "mout_epll");
    if (IS_ERR(mout_epll)) {
        printk(KERN_WARNING "%s: Cannot find mout_epll.\n",
                __func__);
        ret = -EINVAL;
        goto out1;
    }

    sclk_audio0 = clk_get(&pdev->dev, "sclk_audio");
    if (IS_ERR(sclk_audio0)) {
        printk(KERN_WARNING "%s: Cannot find sclk_audio.\n",
                __func__);
        ret = -EINVAL;
        goto out2;
    }

    sclk_spdif = clk_get(NULL, "sclk_spdif");
    if (IS_ERR(sclk_spdif)) {
        printk(KERN_WARNING "%s: Cannot find sclk_spdif.\n",
                __func__);
        ret = -EINVAL;
        goto out3;
    }

    /* Set audio clock hierarchy for S/PDIF */
    clk_set_parent(mout_epll, fout_epll);
    clk_set_parent(sclk_audio0, mout_epll);
    clk_set_parent(sclk_spdif, sclk_audio0);

    clk_put(sclk_spdif);
out3:
    clk_put(sclk_audio0);
out2:
    clk_put(mout_epll);
out1:
    clk_put(fout_epll);

    return ret;
}

/* We should haved to set clock directly on this part because of clock
 * scheme of Samsudng SoCs did not support to set rates from abstrct
 * clock of it's hierarchy.
 */
static int set_audio_clock_rate(unsigned long epll_rate,
                unsigned long audio_rate)
{
    struct clk *fout_epll, *sclk_spdif;

    fout_epll = clk_get(NULL, "fout_epll");
    if (IS_ERR(fout_epll)) {
        printk(KERN_ERR "%s: failed to get fout_epll\n", __func__);
        return -ENOENT;
    }

    clk_set_rate(fout_epll, epll_rate);
    clk_put(fout_epll);

    sclk_spdif = clk_get(NULL, "sclk_spdif");
    if (IS_ERR(sclk_spdif)) {
        printk(KERN_ERR "%s: failed to get sclk_spdif\n", __func__);
        return -ENOENT;
    }

    clk_set_rate(sclk_spdif, audio_rate);
    clk_put(sclk_spdif);

    return 0;
}

static int smdk_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 *cpu_dai = rtd->cpu_dai;
    unsigned long pll_out, rclk_rate;
    int ret, ratio;

    switch (params_rate(params)) {
    case 44100:
        pll_out = 45158400;
        break;
    case 32000:
    case 48000:
    case 96000:
        pll_out = 49152000;
        break;
    default:
        return -EINVAL;
    }

    /* Setting ratio to 512fs helps to use S/PDIF with HDMI without
     * modify S/PDIF ASoC machine driver.
     */
    ratio = 512;
    rclk_rate = params_rate(params) * ratio;

    /* Set audio source clock rates */
    ret = set_audio_clock_rate(pll_out, rclk_rate);
    if (ret < 0)
        return ret;

    /* Set S/PDIF uses internal source clock */
    ret = snd_soc_dai_set_sysclk(cpu_dai, SND_SOC_SPDIF_INT_MCLK,
                    rclk_rate, SND_SOC_CLOCK_IN);
    if (ret < 0)
        return ret;

    return ret;
}

static struct snd_soc_ops smdk_spdif_ops = {
    .hw_params = smdk_hw_params,
};

static struct snd_soc_dai_link smdk_dai = {
    .name = "S/PDIF",
    .stream_name = "S/PDIF PCM Playback",
    .platform_name = "samsung-audio",
    .cpu_dai_name = "samsung-spdif",
    .codec_dai_name = "dit-hifi",
    .codec_name = "spdif-dit",
    .ops = &smdk_spdif_ops,
};

static struct snd_soc_card smdk = {
    .name = "SMDK-S/PDIF",
    .owner = THIS_MODULE,
    .dai_link = &smdk_dai,
    .num_links = 1,
};

static struct platform_device *smdk_snd_spdif_dit_device;
static struct platform_device *smdk_snd_spdif_device;

static int __init smdk_init(void)
{
    int ret;

    smdk_snd_spdif_dit_device = platform_device_alloc("spdif-dit", -1);
    if (!smdk_snd_spdif_dit_device)
        return -ENOMEM;

    ret = platform_device_add(smdk_snd_spdif_dit_device);
    if (ret)
        goto err1;

    smdk_snd_spdif_device = platform_device_alloc("soc-audio", -1);
    if (!smdk_snd_spdif_device) {
        ret = -ENOMEM;
        goto err2;
    }

    platform_set_drvdata(smdk_snd_spdif_device, &smdk);

    ret = platform_device_add(smdk_snd_spdif_device);
    if (ret)
        goto err3;

    /* Set audio clock hierarchy manually */
    ret = set_audio_clock_heirachy(smdk_snd_spdif_device);
    if (ret)
        goto err4;

    return 0;
err4:
    platform_device_del(smdk_snd_spdif_device);
err3:
    platform_device_put(smdk_snd_spdif_device);
err2:
    platform_device_del(smdk_snd_spdif_dit_device);
err1:
    platform_device_put(smdk_snd_spdif_dit_device);
    return ret;
}

static void __exit smdk_exit(void)
{
    platform_device_unregister(smdk_snd_spdif_device);
    platform_device_unregister(smdk_snd_spdif_dit_device);
}

module_init(smdk_init);
module_exit(smdk_exit);

MODULE_AUTHOR("Seungwhan Youn, <[email protected]>");
MODULE_DESCRIPTION("ALSA SoC SMDK+S/PDIF");
MODULE_LICENSE("GPL");