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smdk_spdif.c

/*
 * 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 <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",
      .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, <sw.youn@samsung.com>");
MODULE_DESCRIPTION("ALSA SoC SMDK+S/PDIF");
MODULE_LICENSE("GPL");

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