From mboxrd@z Thu Jan 1 00:00:00 1970 From: inki.dae@samsung.com (Inki Dae) Date: Thu, 08 Mar 2018 15:50:33 +0900 Subject: [PATCH] dt-bindings: exynos: Document #sound-dai-cells property of the HDMI node In-Reply-To: <3c68c3da-a0c3-4e4e-da6b-3e4b1af6d19d@samsung.com> References: <20180307171111.14551-1-s.nawrocki@samsung.com> <5AA0B59F.3070402@samsung.com> <3c68c3da-a0c3-4e4e-da6b-3e4b1af6d19d@samsung.com> Message-ID: <5AA0DD39.3040108@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 >>> --- >>> 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