[PATCH] dt-bindings: exynos: Document #sound-dai-cells property of the HDMI node

[inki.dae@samsung.com (Inki Dae)]

Hi Marek,

2018? 03? 08? 15:29? Marek Szyprowski ?(?) ? ?:
> Hi Inki,
> 
> On 2018-03-08 05:01, Inki Dae wrote:
>> Hi Sylwester,
>>
>> 2018? 03? 08? 02:11? Sylwester Nawrocki ?(?) ? ?:
>>> The #sound-dai-cells DT property is required to describe link between
>>> the HDMI IP block and the SoC's audio subsystem.
>>>
>>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>>> ---
>>>   Documentation/devicetree/bindings/display/exynos/exynos_hdmi.txt | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/exynos/exynos_hdmi.txt b/Documentation/devicetree/bindings/display/exynos/exynos_hdmi.txt
>>> index 8715ff06c457..6b2a526ec586 100644
>>> --- a/Documentation/devicetree/bindings/display/exynos/exynos_hdmi.txt
>>> +++ b/Documentation/devicetree/bindings/display/exynos/exynos_hdmi.txt
>>> @@ -50,6 +50,9 @@ Required properties for Exynos 5433:
>>>   - clock-names: aliases for above clock specfiers.
>>>   - samsung,sysreg: handle to syscon used to control the system registers.
>>>   +Optional properties for Exynos 4210, 4212, 5420 and 5433:
>>> + - #sound-dai-cells: should be 0.
>>> +
>> Just trivial question. 'sound-dai-cells' property could affect hdmi driver? I looked into HDMI codec driver but I didn't find relevat code.
>> I mean that if this property never affect HDMI driver then this property would be a dead thing even through this can be declared optionally.
> 
> This property is used by ASoC framework when it is building connections
> between all elements of the virtual 'sound card'. It allows generic
> code to find proper driver for the digital audio interface (DAI) object.

I also assumed that some place of ASoC framework checks this property. For this I looked into HDMI codec driver(sound/soc/codecs/hdmi-codec.c) and relevant interfaces of ASoC framework.
But I couldn't find it. :( Could you let me know which code of ASoC framework checks this? I saw this property only in 'snd_soc_of_get_dai_name' and 'snd_soc_of_get_dai_link_codecs' functions but seems these functions aren't called by the HDMI codec driver.

Thanks,
Inki Dae

> 
> Best regards