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Message-ID: <fa01ef26-d4d4-4c62-9c12-1f8bed1cfdab@denx.de>
Date: Thu, 16 May 2024 13:44:08 +0200
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Subject: Re: [PATCH] arm64: dts: imx8mp: Enable HDMI on i.MX8MP DHCOM PDK2 and
 PDK3
To: Ahmad Fatoum <a.fatoum@pengutronix.de>,
 Francesco Dolcini <francesco@dolcini.it>
Cc: Rob Herring <robh@kernel.org>, Conor Dooley <conor+dt@kernel.org>,
 devicetree@vger.kernel.org, Shawn Guo <shawnguo@kernel.org>,
 Sascha Hauer <s.hauer@pengutronix.de>, linux-kernel@vger.kernel.org,
 imx@lists.linux.dev, kernel@dh-electronics.com,
 Pengutronix Kernel Team <kernel@pengutronix.de>,
 Krzysztof Kozlowski <krzk+dt@kernel.org>, Fabio Estevam
 <festevam@gmail.com>, linux-arm-kernel@lists.infradead.org
References: <20240514010706.245874-1-marex@denx.de>
 <20240516080008.GA9338@francesco-nb>
 <76b3cee8-1fe3-4192-b8c9-7a9c2b7165f0@denx.de>
 <b354724f-5235-4519-8361-b8209ab99d36@pengutronix.de>
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From: Marek Vasut <marex@denx.de>
In-Reply-To: <b354724f-5235-4519-8361-b8209ab99d36@pengutronix.de>
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On 5/16/24 1:36 PM, Ahmad Fatoum wrote:
> Hello Marek,

Hi,

> On 16.05.24 13:14, Marek Vasut wrote:
>> On 5/16/24 10:00 AM, Francesco Dolcini wrote:
>>> Hello Marek,
>>
>> Hi,
>>
>>> On Tue, May 14, 2024 at 03:06:42AM +0200, Marek Vasut wrote:
>>>> Enable HDMI output on i.MX8MP DHCOM PDK2 and PDK3. The I2C5 on PDK2 and
>>>> I2C mux port 1 on PDK3 respectively are used in regular I2C mode instead
>>>> of HDMI DDC mode to permit connection of other I2C devices on those buses.
>>>
>>> Are you able to read the HDMI EDID with such configuration? I have the
>>> patch ready for verdin imx8mp, I just did not have time to figure out
>>> this last details.
>>
>> Yes with ddc-i2c-bus in hdmi_tx{} node, no with ddc-i2c-bus in connector node. Maybe that's what you're running into ? The DW HDMI core needs the ddc-i2c-bus property in hdmi_tx{} node if you use non-native I2C bus for the DDC channel.
> 
> What benefit does the hdmi-connector provide over just omitting it?
> Just for documentation purposes?

I was under the impression describing the hardware in DT in full was the 
best practice (TM), hence it is in full here.