Re: [PATCH] drm: bridge/dw_hdmi: add audio sample channel status setting

[Cheng-yi Chiang <cychiang@chromium.org>]

On Wed, Sep 4, 2019 at 4:33 AM Jonas Karlman <jonas@kwiboo.se> wrote:
>
> On 2019-09-03 20:08, Jernej Škrabec wrote:
> > Hi!
> >
> > Dne torek, 03. september 2019 ob 20:00:33 CEST je Neil Armstrong napisal(a):
> >> Hi,
> >>
> >> Le 03/09/2019 à 11:53, Neil Armstrong a écrit :
> >>> Hi,
> >>>
> >>> On 03/09/2019 07:51, Cheng-Yi Chiang wrote:
> >>>> From: Yakir Yang <ykk@rock-chips.com>
> >>>>
> >>>> When transmitting IEC60985 linear PCM audio, we configure the
> >>>> Audio 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)
> >>>>
> >>>> Signed-off-by: Yakir Yang <ykk@rock-chips.com>
> >>>> Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
> >>>> ---
> >>>>
> >>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 59 +++++++++++++++++++++++
> >>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.h | 20 ++++++++
> >>>>  2 files changed, 79 insertions(+)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> >>>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index
> >>>> bd65d0479683..34d46e25d610 100644
> >>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> >>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> >>>> @@ -582,6 +582,63 @@ static unsigned int hdmi_compute_n(unsigned int
> >>>> freq, unsigned long pixel_clk)>>
> >>>>    return n;
> >>>>
> >>>>  }
> >>>>
> >>>> +static void hdmi_set_schnl(struct dw_hdmi *hdmi)
> >>>> +{
> >>>> +  u8 aud_schnl_samplerate;
> >>>> +  u8 aud_schnl_8;
> >>>> +
> >>>> +  /* These registers are on RK3288 using version 2.0a. */
> >>>> +  if (hdmi->version != 0x200a)
> >>>> +          return;
> >>> Are these limited to the 2.0a version *in* RK3288, or 2.0a version on all
> >>> SoCs ?
> >> After investigations, Amlogic sets these registers on their 2.0a version
> >> aswell, and Jernej (added in Cc) reported me Allwinner sets them on their
> >> < 2.0a and > 2.0a IPs versions.
> >>
> >> Can you check on the Rockchip IP versions in RK3399 ?
> >>
> >> For reference, the HDMI 1.4a IP version allwinner setups is:
> >> https://github.com/Allwinner-Homlet/H3-BSP4.4-linux/blob/master/drivers/vide
> >> o/fbdev/sunxi/disp2/hdmi/hdmi_bsp_sun8iw7.c#L531-L539 (registers a
> >> "scrambled" but a custom bit can reset to the original mapping, 0x1066 ...
> >> 0x106f)
> > For easier reading, here is similar, but annotated version: http://ix.io/1Ub6
> > Check function bsp_hdmi_audio().
> >
> > Unless there is a special reason, you can just remove that check.
>
> Agree, this check should not be needed, AUDSCHNLS7 used to be configured in my old
> multi-channel patches that have seen lot of testing on Amlogic, Allwinner and Rockchip SoCs.
>

As stated in previous mail, I will modify the check for version >=1.4
since I know that 1.3 does not have such register, at least on iMX6.

> >
> > Best regards,
> > Jernej
> >
> >> Neil
> >>
> >>>> +
> >>>> +  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;
> >>>> +
> >>>> +  /* This means word length is 16 bit. Refer to IEC60958-3 page 12. */
> >>>> +  aud_schnl_8 |= 2 << HDMI_FC_AUDSCHNLS8_WORDLEGNTH_OFFSET;
>
> This looks wrong, user can use 16 and 24 bit wide audio streams.
>

Thanks for spotting this issue.
I will fix it in v2 (following how http://ix.io/1Ub6 set it for 16 and 24 bit)

> >>>> +
> >>>> +  hdmi_writeb(hdmi, aud_schnl_8, HDMI_FC_AUDSCHNLS8);
> >>>> +}
> >>>> +
> >>>>
> >>>>  static void hdmi_set_clk_regenerator(struct dw_hdmi *hdmi,
> >>>>
> >>>>    unsigned long pixel_clk, unsigned int sample_rate)
> >>>>
> >>>>  {
> >>>>
> >>>> @@ -620,6 +677,8 @@ static void hdmi_set_clk_regenerator(struct dw_hdmi
> >>>> *hdmi,>>
> >>>>    hdmi->audio_cts = cts;
> >>>>    hdmi_set_cts_n(hdmi, cts, hdmi->audio_enable ? n : 0);
> >>>>    spin_unlock_irq(&hdmi->audio_lock);
> >>>>
> >>>> +
> >>>> +  hdmi_set_schnl(hdmi);
>
> I will suggest this function is called from or merged with dw_hdmi_set_sample_rate().
> Similar to how AUDSCONF and AUDICONF0 is configured from dw_hdmi_set_channel_count().
>

I see. I think it will make sense to add a function
set_channel_status() for dw-hdmi-i2s-audio.c to call,
since this function is more than just setting rate.
Will fix in v2.

Thanks!

> Regards,
> Jonas
>
> >>>>
> >>>>  }
> >>>>
> >>>>  static void hdmi_init_clk_regenerator(struct dw_hdmi *hdmi)
> >>>>
> >>>> 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,
> >>>>
> >>>>  /* HDMI_FC_AUDSCHNLS8 field values */
> >>>>
> >>>>    HDMI_FC_AUDSCHNLS8_ORIGSAMPFREQ_MASK = 0xf0,