Re: [PATCH v3] drm: bridge/dw_hdmi: add audio sample channel status setting

[Jonas Karlman]

On 2019-09-11 19:02, Cheng-yi Chiang wrote:
> On Thu, Sep 12, 2019 at 12:54 AM Jernej Åkrabec <jernej.skrabec@xxxxxxxx> wrote:
>> Dne sreda, 11. september 2019 ob 18:23:59 CEST je Neil Armstrong napisal(a):
>>> On 11/09/2019 10:26, Cheng-Yi Chiang wrote:
>>>> From: Yakir Yang <ykk@xxxxxxxxxxxxxx>
>>>>
>>>> When transmitting IEC60985 linear PCM audio, we configure the
>>>> Aduio Sample Channel Status information in the IEC60958 frame.
>>>> The status bit is already available in iec.status of hdmi_codec_params.
>>>>
>>>> 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@xxxxxxxxxxxxxx>
>>>> Signed-off-by: Cheng-Yi Chiang <cychiang@xxxxxxxxxxxx>
>>>> ---
>>>>
>>>> Change from v2 to v3:
>>>> 1. Reuse what is already set in iec.status in hw_param.
>>>> 2. Remove all useless definition of registers and values.
>>>> 3. Note that the original sampling frequency is not written to
>>>>
>>>>    the channel status as we reuse create_iec958_consumer in pcm_iec958.c.
>>>>    Without that it can still play audio fine.
>>>>
>>>>  .../drm/bridge/synopsys/dw-hdmi-i2s-audio.c   |  1 +
>>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c     | 20 +++++++++++++++++++
>>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.h     |  2 ++
>>>>  include/drm/bridge/dw_hdmi.h                  |  1 +
>>>>  4 files changed, 24 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..20f4f92dd866 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->iec.status);
>>>>
>>>>     dw_hdmi_set_channel_count(hdmi, hparms->channels);
>>>>     dw_hdmi_set_channel_allocation(hdmi, hparms-
>>> cea.channel_allocation);
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index
>>>> bd65d0479683..aa7efd4da1c8 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>>> @@ -582,6 +582,26 @@ 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,
>>>> +                           u8 *channel_status)
>>>> +{
>>>> +   /*
>>>> +    * Set channel status register for frequency and word length.
>>>> +    * Use default values for other registers.
>>>> +    */
>>>> +   hdmi_writeb(hdmi, channel_status[3], HDMI_FC_AUDSCHNLS7);
>>>> +   hdmi_writeb(hdmi, channel_status[4], HDMI_FC_AUDSCHNLS8);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(dw_hdmi_set_channel_status);
>>>> +
>>>>
>>>>  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..fcff5059db24 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
>>>> @@ -158,6 +158,8 @@
>>>>
>>>>  #define HDMI_FC_SPDDEVICEINF                    0x1062
>>>>  #define HDMI_FC_AUDSCONF                        0x1063
>>>>  #define HDMI_FC_AUDSSTAT                        0x1064
>>>>
>>>> +#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
>>>>
>>>> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
>>>> index cf528c289857..4b3e863c4f8a 100644
>>>> --- a/include/drm/bridge/dw_hdmi.h
>>>> +++ b/include/drm/bridge/dw_hdmi.h
>>>> @@ -156,6 +156,7 @@ 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, u8
>>>> *channel_status);
>>>>
>>>>  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);
>>> Looks fine for me:
>>> Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>>>
>>> Jonas ? Jernej ? Russell ?
>> Patch itself is fine, I'm just wondering if more information should be copied
>> from status array to registers. But I think they are not 1:1 mapping so some
>> more work would be needed. Anyway, patch is:
> Hi Jernej,
> Yes you are right. I was thinking about the same thing.
> But there are also some fields in the IEC60958 spec not mapped to the
> registers on dw-hdmi.
> So I ended up just writing the two registers in the original ykk's
> patch, and ignoring "original sampling frequency" like pcm_iec958.
> It turns out that audio plays fine on my LG monitor. So I suggest we
> can keep this patch as simple as it is, and add more register setting
> if we find issue.
> Thanks!

In my old multi-channel lpcm patch [1] I only wrote sample rate to FC_AUDSCHNLS7.
This is much cleaner and simpler, and setting FC_AUDSCHNLS8 does not cause any
problems when I tested on ASUS Tinker Board S (RK3288).

Reviewed-by: Jonas Karlman <jonas@xxxxxxxxx>


[1] https://github.com/Kwiboo/linux-rockchip/commit/4af9ebc567ccf0a0851fa260097021c27aebbb6b

Regards,
Jonas

>
>>
>> Reviewed-by: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
>>
>> Best regards,
>> Jernej
>>
>>> If it's ok for you I'll apply it.
>>>
>>> Neil
>>>