Hi Inki,
On 03/09/2018 03:40 AM, Inki Dae wrote:
> 2018년 03월 08일 02:27에 Sylwester Nawrocki 이(가) 쓴 글:
>> This property is required for specifying link between the HDMI IP block
>> and the SoC's audio subsystem.
>>
>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
>> ---
>> arch/arm/boot/dts/exynos5250.dtsi | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi
>> index 56626d1a4235..71d2ede118e3 100644
>> --- a/arch/arm/boot/dts/exynos5250.dtsi
>> +++ b/arch/arm/boot/dts/exynos5250.dtsi
>> @@ -700,6 +700,7 @@
>> "sclk_hdmiphy", "mout_hdmi";
>> samsung,syscon-phandle = <&pmu_system_controller>;
>> phy = <&hdmiphy>;
>> + #sound-dai-cells = <0>;
>
> This patch adds this property to hdmi device node which is bound by HDMI driver
> of Exynos DRM. As we talked about this at other email thread, seems this property
> is required mandatorily for Odroid XU3/4 board which uses Exynos5422.
> There may be something I'm missing so could you let me know how this property
> is required?
It is required to properly interpret the list of DAI specified in the 'sound-dai'
property. If a device supports only one DAI it will have #sound-dai-cells = <0>
and the sound-dai property values in cpu<->codec link may look like this:
cpu { ... }
codec {
sound-dai = <&max98090>, <&hdmi>;
};
When the CODEC support more DAIs it will have #sound-dai-cells = <1> and we can
additionally specify which DAI we exactly refer to, in this case DAI 0:
cpu { ... }
codec {
sound-dai = <&max98095 0>, <&hdmi>;
};
More details can be found in documentation of of_parse_phandle_with_args()
function.
The above refers to cpu/codec mapping like I2S0 -> [max9809x, hdmi], on Exynos5433
we have I2S0 -> wm5110 and I2S1 -> hdmi.
--
Regards,
Sylwester
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