Re: [PATCH] drm: zte: support hdmi audio through spdif

On Thu, Dec 22, 2016 at 10:18:00AM -0500, Sean Paul wrote:

On Thu, Dec 22, 2016 at 8:11 AM, Shawn Guo shawnguo@kernel.org wrote:

...

+static int zx_hdmi_audio_get_n(unsigned int fs) +{

•   unsigned int n;
  

•   switch (fs) {
  

•   case 32000:
  

•           n = 4096;
  

•           break;
  

•   case 44100:
  

•           n = 6272;
  

•           break;
  

•   case 48000:
  

•           n = 6144;
  

•           break;
  

•   case 88200:
  

•           n = 6272 * 2;
  

•           break;
  

•   case 96000:
  

•           n = 6144 * 2;
  

•           break;
  

•   case 176400:
  

•           n = 6272 * 4;
  

•           break;
  

•   case 192000:
  

•           n = 6144 * 4;
  

•           break;
  

•   default:
  

•           n = fs * 128 / 1000;
  

It seems like this could be distilled down to:

if (fs && (fs % 44100) == 0) n = 6272 * (fs / 44100); else n = fs * 128 / 1000;

Nice! Thanks for the suggestion.

...

•   }
  

•   return n;
  

+}

+static int zx_hdmi_audio_hw_params(struct device *dev,

•                              void *data,
  

•                              struct hdmi_codec_daifmt *daifmt,
  

•                              struct hdmi_codec_params *params)
  

+{

•   struct zx_hdmi *hdmi = dev_get_drvdata(dev);
  

•   struct hdmi_audio_infoframe *cea = &params->cea;
  

•   union hdmi_infoframe frame;
  

•   int n;
  

•   /* We only support spdif for now */
  

•   if (daifmt->fmt != HDMI_SPDIF) {
  

•           DRM_DEV_ERROR(hdmi->dev, "invalid daifmt %d\n", daifmt->fmt);
  

•           return -EINVAL;
  

•   }
  

•   switch (params->sample_width) {
  

•   case 16:
  

•           hdmi_writeb_mask(hdmi, TPI_AUD_CONFIG, SPDIF_SAMPLE_SIZE_MASK,
  

•                            SPDIF_SAMPLE_SIZE_16BIT);
  

•           break;
  

•   case 20:
  

•           hdmi_writeb_mask(hdmi, TPI_AUD_CONFIG, SPDIF_SAMPLE_SIZE_MASK,
  

•                            SPDIF_SAMPLE_SIZE_20BIT);
  

•           break;
  

•   case 24:
  

•           hdmi_writeb_mask(hdmi, TPI_AUD_CONFIG, SPDIF_SAMPLE_SIZE_MASK,
  

•                            SPDIF_SAMPLE_SIZE_24BIT);
  

•           break;
  

•   default:
  

•           DRM_DEV_ERROR(hdmi->dev, "invalid sample width %d\n",
  

•                         params->sample_width);
  

•           return -EINVAL;
  

•   }
  

•   /* CTS is calculated by hardware, and we only need to take care of N */
  

•   n = zx_hdmi_audio_get_n(params->sample_rate);
  

•   hdmi_writeb(hdmi, N_SVAL1, n & 0xff);
  

•   hdmi_writeb(hdmi, N_SVAL2, (n >> 8) && 0xff);
  

s/&&/&/ ?

Oops! Thanks for catching it.

Shawn

...

•   hdmi_writeb(hdmi, N_SVAL3, (n >> 16) & 0xf);
  

•   /* Enable spdif mode */
  

•   hdmi_writeb_mask(hdmi, AUD_MODE, SPDIF_EN, SPDIF_EN);
  

•   /* Enable audio input */
  

•   hdmi_writeb_mask(hdmi, AUD_EN, AUD_IN_EN, AUD_IN_EN);
  

•   memcpy(&frame.audio, cea, sizeof(*cea));
  

•   return zx_hdmi_infoframe_trans(hdmi, &frame, FSEL_AUDIO);
  

+}