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

From: Neil Armstrong
Date: Fri Sep 13 2019 - 04:46:19 EST

On 13/09/2019 08:37, Jonas Karlman wrote:
> 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

Thanks Jonas, Jernej,

Applying now.

Neil

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