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From:   Cheng-yi Chiang <cychiang@chromium.org>
Date:   Mon, 9 Sep 2019 10:29:18 +0800
Message-ID: <CAFv8NwJV2ogJu99AN2T4OusDJ-h=PTHQHABNYtcAdazePJ7gBQ@mail.gmail.com>
Subject: Re: [PATCH v2] drm: bridge/dw_hdmi: add audio sample channel status setting
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        "moderated list:SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEM..." 
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On Mon, Sep 9, 2019 at 2:38 AM Russell King - ARM Linux admin
<linux@armlinux.org.uk> wrote:
>
> On Thu, Sep 05, 2019 at 05:43:25PM +0800, Cheng-Yi Chiang wrote:
> > From: Yakir Yang <ykk@rock-chips.com>
> >
> > When transmitting IEC60985 linear PCM audio, we configure the
> > Aduio Sample Channel Status information of all the channel
> > status bits in the IEC60958 frame.
> > Refer to 60958-3 page 10 for frequency, original frequency, and
> > wordlength setting.
> >
> > This fix the issue that audio does not come out on some monitors
> > (e.g. LG 22CV241)
> >
> > Note that these registers are only for interfaces:
> > I2S audio interface, General Purpose Audio (GPA), or AHB audio DMA
> > (AHBAUDDMA).
> > For S/PDIF interface this information comes from the stream.
> >
> > Currently this function dw_hdmi_set_channel_status is only called
> > from dw-hdmi-i2s-audio in I2S setup.
> >
> > Signed-off-by: Yakir Yang <ykk@rock-chips.com>
> > Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
> > ---
> >  Original patch by Yakir Yang is at
> >
> >  https://lore.kernel.org/patchwork/patch/539653/
> >
> >  Change from v1 to v2:
> >  1. Remove the version check because this will only be called by
> >     dw-hdmi-i2s-audio, and the registers are available in I2S setup.
> >  2. Set these registers in dw_hdmi_i2s_hw_params.
> >  3. Fix the sample width setting so it can use 16 or 24 bits.
> >
> >  .../drm/bridge/synopsys/dw-hdmi-i2s-audio.c   |  1 +
> >  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     | 70 +++++++++++++++++++
> >  drivers/gpu/drm/bridge/synopsys/dw-hdmi.h     | 20 ++++++
> >  include/drm/bridge/dw_hdmi.h                  |  2 +
> >  4 files changed, 93 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> > index 34d8e837555f..b801a28b0f17 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
> > @@ -102,6 +102,7 @@ static int dw_hdmi_i2s_hw_params(struct device *dev, void *data,
> >       }
> >
> >       dw_hdmi_set_sample_rate(hdmi, hparms->sample_rate);
> > +     dw_hdmi_set_channel_status(hdmi, hparms->sample_width);
> >       dw_hdmi_set_channel_count(hdmi, hparms->channels);
> >       dw_hdmi_set_channel_allocation(hdmi, hparms->cea.channel_allocation);
> >
>
> dw_hdmi_i2s_hw_params() is passed the channel status data in
> hparams->iec.status  Rather than re-creating it afresh in the driver,
> I'd recommend programming the already supplied channel status data
> into the registers.
>

Hi Russell,
Thank you for pointing this out.
I did not realize that the status data is already set.
I will fix in v3 to make this patch much simpler.

> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > index bd65d0479683..d1daa369c8ae 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > @@ -582,6 +582,76 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk)
> >       return n;
> >  }
> >
> > +/*
> > + * When transmitting IEC60958 linear PCM audio, these registers allow to
> > + * configure the channel status information of all the channel status
> > + * bits in the IEC60958 frame. For the moment this configuration is only
> > + * used when the I2S audio interface, General Purpose Audio (GPA),
> > + * or AHB audio DMA (AHBAUDDMA) interface is active
> > + * (for S/PDIF interface this information comes from the stream).
> > + */
> > +void dw_hdmi_set_channel_status(struct dw_hdmi *hdmi,
> > +                             unsigned int sample_width)
> > +{
> > +     u8 aud_schnl_samplerate;
> > +     u8 aud_schnl_8;
> > +     u8 word_length_bits;
> > +
> > +     switch (hdmi->sample_rate) {
> > +     case 32000:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_32K;
> > +             break;
> > +     case 44100:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_44K1;
> > +             break;
> > +     case 48000:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_48K;
> > +             break;
> > +     case 88200:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_88K2;
> > +             break;
> > +     case 96000:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_96K;
> > +             break;
> > +     case 176400:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_176K4;
> > +             break;
> > +     case 192000:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_192K;
> > +             break;
> > +     case 768000:
> > +             aud_schnl_samplerate = HDMI_FC_AUDSCHNLS7_SMPRATE_768K;
> > +             break;
> > +     default:
> > +             dev_warn(hdmi->dev, "Unsupported audio sample rate (%u)\n",
> > +                      hdmi->sample_rate);
> > +             return;
> > +     }
> > +
> > +     /* set channel status register */
> > +     hdmi_modb(hdmi, aud_schnl_samplerate, HDMI_FC_AUDSCHNLS7_SMPRATE_MASK,
> > +               HDMI_FC_AUDSCHNLS7);
> > +
> > +     /*
> > +      * Set original frequency to be the same as frequency.
> > +      * Use one-complement value as stated in IEC60958-3 page 13.
> > +      */
> > +     aud_schnl_8 = (~aud_schnl_samplerate) <<
> > +                     HDMI_FC_AUDSCHNLS8_ORIGSAMPFREQ_OFFSET;
> > +
> > +     /*
> > +      * Refer to IEC60958-3 page 12. We can accept 16 bits or 24 bits.
> > +      * Otherwise, set the register to 0t o indicate using default value.
> > +      */
> > +     word_length_bits = (sample_width == 16) ? 0x2 :
> > +                         ((sample_width == 24) ? 0xb : 0);
> > +
> > +     aud_schnl_8 |= word_length_bits << HDMI_FC_AUDSCHNLS8_WORDLEGNTH_OFFSET;
> > +
> > +     hdmi_writeb(hdmi, aud_schnl_8, HDMI_FC_AUDSCHNLS8);
> > +}
> > +EXPORT_SYMBOL_GPL(dw_hdmi_set_channel_status);
>
> As mentioned above, the channel status data is actually already
> provided - so we don't really need the above at all.  It just
> needs the data programmed into the registers.
>
ACK
> > +
> >  static void hdmi_set_clk_regenerator(struct dw_hdmi *hdmi,
> >       unsigned long pixel_clk, unsigned int sample_rate)
> >  {
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
> > index 6988f12d89d9..619ebc1c8354 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
> > @@ -158,6 +158,17 @@
> >  #define HDMI_FC_SPDDEVICEINF                    0x1062
> >  #define HDMI_FC_AUDSCONF                        0x1063
> >  #define HDMI_FC_AUDSSTAT                        0x1064
> > +#define HDMI_FC_AUDSV                           0x1065
> > +#define HDMI_FC_AUDSU                           0x1066
> > +#define HDMI_FC_AUDSCHNLS0                      0x1067
> > +#define HDMI_FC_AUDSCHNLS1                      0x1068
> > +#define HDMI_FC_AUDSCHNLS2                      0x1069
> > +#define HDMI_FC_AUDSCHNLS3                      0x106a
> > +#define HDMI_FC_AUDSCHNLS4                      0x106b
> > +#define HDMI_FC_AUDSCHNLS5                      0x106c
> > +#define HDMI_FC_AUDSCHNLS6                      0x106d
> > +#define HDMI_FC_AUDSCHNLS7                      0x106e
> > +#define HDMI_FC_AUDSCHNLS8                      0x106f
> >  #define HDMI_FC_DATACH0FILL                     0x1070
> >  #define HDMI_FC_DATACH1FILL                     0x1071
> >  #define HDMI_FC_DATACH2FILL                     0x1072
> > @@ -706,6 +717,15 @@ enum {
> >  /* HDMI_FC_AUDSCHNLS7 field values */
> >       HDMI_FC_AUDSCHNLS7_ACCURACY_OFFSET = 4,
> >       HDMI_FC_AUDSCHNLS7_ACCURACY_MASK = 0x30,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_MASK = 0x0f,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_192K = 0xe,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_176K4 = 0xc,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_96K = 0xa,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_768K = 0x9,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_88K2 = 0x8,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_32K = 0x3,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_48K = 0x2,
> > +     HDMI_FC_AUDSCHNLS7_SMPRATE_44K1 = 0x0,
>
> These look very much like the IEC958_AES* consumer definitions in
> include/sound/asoundef.h.
ACK. Will remove in v3.
>
> >  /* HDMI_FC_AUDSCHNLS8 field values */
> >       HDMI_FC_AUDSCHNLS8_ORIGSAMPFREQ_MASK = 0xf0,
> > diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
> > index cf528c289857..12144d2f80f4 100644
> > --- a/include/drm/bridge/dw_hdmi.h
> > +++ b/include/drm/bridge/dw_hdmi.h
> > @@ -156,6 +156,8 @@ void dw_hdmi_setup_rx_sense(struct dw_hdmi *hdmi, bool hpd, bool rx_sense);
> >
> >  void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate);
> >  void dw_hdmi_set_channel_count(struct dw_hdmi *hdmi, unsigned int cnt);
> > +void dw_hdmi_set_channel_status(struct dw_hdmi *hdmi,
> > +                             unsigned int sample_width);
> >  void dw_hdmi_set_channel_allocation(struct dw_hdmi *hdmi, unsigned int ca);
> >  void dw_hdmi_audio_enable(struct dw_hdmi *hdmi);
> >  void dw_hdmi_audio_disable(struct dw_hdmi *hdmi);
> > --
> > 2.23.0.187.g17f5b7556c-goog
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
>
> --
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