Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 1/4] ARM: dts: exynos5250: Add #sound-dai-cells property
 to hdmi device node
To:     Inki Dae <inki.dae@samsung.com>
Cc:     krzk@kernel.org, kgene@kernel.org, devicetree@vger.kernel.org,
        linux-samsung-soc@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        b.zolnierkie@samsung.com, m.szyprowski@samsung.com
From:   Sylwester Nawrocki <s.nawrocki@samsung.com>
Message-id: <21459bbe-befc-da77-5c34-c821db74ae8d@samsung.com>
Date:   Wed, 14 Mar 2018 11:33:37 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
        Thunderbird/52.6.0
MIME-version: 1.0
In-reply-to: <5AA5CE4F.6050807@samsung.com>
Content-type: text/plain; charset="utf-8"
Content-language: en-GB
Content-transfer-encoding: 7bit
CMS-TYPE: 102P
References: <CGME20180307172723epcas1p1b8879bb555737cab7406a172b7d13a56@epcas1p1.samsung.com>
        <20180307172711.15697-1-s.nawrocki@samsung.com>
        <5AA1F41B.5080104@samsung.com>
        <39965bce-a6f2-6202-5c3f-97e4446e97eb@samsung.com>
        <5AA5CE4F.6050807@samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Inki,

On 03/12/2018 01:48 AM, Inki Dae wrote:
> Thanks for explanation. By the way, who binds '#sound-dai-cells' property?.
> This patch adds this property to hdmi device node which will be bound by 
> HDMI driver fo Exynos DRM but I don't see any place to bind '#sound-dai-cells' 
> property in this driver.
> So I think some driver like Odroid XU3/4 audio driver(sound/soc/samsung/odroid.c) 
> or ASoC simple audio card driver(sound/soc/generic/simple-card.c) should exist 
> and this property should be placed to such device node.

The *-cells property is supposed to be in a node that a phandle points to,
and in this case the phandle entry in 'sound-dai' points to the hdmi node.
From the DT bindings perspective it not that important how Linux parses
the bindings, it's more a matter of describing the HW configuration.

There is even a related check in dtc:

$ grep -n sound scripts/dtc/checks.c
1208:WARNING_PROPERTY_PHANDLE_CELLS(sound_dai, "sound-dai", "#sound-dai-cells");

-- 
Regards,
Sylwester