Hi Inki,

On 2018-03-08 07:50, Inki Dae wrote:
2018년 03월 08일 15:29에 Marek Szyprowski 이(가) 쓴 글:
On 2018-03-08 05:01, Inki Dae wrote:
2018년 03월 08일 02:11에 Sylwester Nawrocki 이(가) 쓴 글:
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.nawro...@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 
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.

It is used by snd_soc_of_get_dai_link_codecs() function, which is called
from respective board/machine driver. See sound/soc/samsung/odroid.c for
good example. It allows to automatically create connection to max98090 and
hdmi codec devices, which are specified in 'sound/codec' node (see

Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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