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Date: Tue, 13 Feb 2024 00:00:15 +0100
From: Sebastian Reichel <sre@kernel.org>
To: Stefan Wahren <wahrenst@gmx.net>
Cc: Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Shawn Guo <shawnguo@kernel.org>, Sascha Hauer <s.hauer@pengutronix.de>, 
	Fabio Estevam <festevam@gmail.com>, Pengutronix Kernel Team <kernel@pengutronix.de>, 
	NXP Linux Team <linux-imx@nxp.com>, Dong Aisheng <aisheng.dong@nxp.com>, 
	Linus Walleij <linus.walleij@linaro.org>, Dmitry Torokhov <dmitry.torokhov@gmail.com>, 
	Mark Brown <broonie@kernel.org>, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 14/14] ARM: dts: imx6ull-uti260b: Add board
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 <20240210012114.489102-15-sre@kernel.org>
 <c38e7c68-e725-4174-aa0a-0594a55c8d56@gmx.net>
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In-Reply-To: <c38e7c68-e725-4174-aa0a-0594a55c8d56@gmx.net>

Hi Stefan,

On Mon, Feb 12, 2024 at 07:28:36PM +0100, Stefan Wahren wrote:
> > +	reg_vsd: regulator-vsd {
> i think the node name should be just "regulator"
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "VSD_3V3";
> > +		regulator-min-microvolt = <3300000>;
> > +		regulator-max-microvolt = <3300000>;
> > +	};
> > +
> > +	reg_vref: regulator-vref-4v2 {
> dito

The nodename must be unique. So just "regulator" does not work. In
the past this was sometimes solved by adding something like @0,
which is part of the nodename. But that is not ok, since there is no
reg property.

> > +&ecspi3 {
> > +	cs-gpios = <&gpio1 20 GPIO_ACTIVE_LOW>;
> > +	pinctrl-names = "default";
> > +	pinctrl-0 = <&mux_spi3>, <&mux_spi3_cs>;
> > +	status = "okay";
> > +
> > +	panel@0 {
> > +		compatible = "inanbo,t28cp45tn89-v17";
> > +		reg = <0>;
> > +		backlight = <&panel_backlight>;
> > +		power-supply = <&reg_vsd>;
> > +		spi-cpha;
> > +		spi-cpol;
> > +		spi-max-frequency = <100000>;
>
> This seems slow to me. Is this a limitation of the display?

I just used something slow, which should definitely work. I will try
to increase to 1MHz. Note, that the display is not driven via SPI.
SPI is just used for the configuration.

Thanks for the review,

-- Sebastian