linux-kernel - Re: [PATCH 4/4] arm64: dts: qcom: Add support for X1-based Surface Laptop 7 devices

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Message-ID: <077566b6-83b0-41cb-8133-52a26aa05a8b@kernel.org>
Date: Fri, 9 Aug 2024 12:22:45 +0200
From: Konrad Dybcio <konradybcio@...nel.org>
To: Stephan Gerhold <stephan.gerhold@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Marijn Suijten <marijn.suijten@...ainline.org>,
 linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, Konrad Dybcio <quic_kdybcio@...cinc.com>
Subject: Re: [PATCH 4/4] arm64: dts: qcom: Add support for X1-based Surface
 Laptop 7 devices

On 9.08.2024 11:07 AM, Stephan Gerhold wrote:
> On Fri, Aug 09, 2024 at 03:43:23AM +0200, Konrad Dybcio wrote:
>> From: Konrad Dybcio <quic_kdybcio@...cinc.com>
>>
>> Add support for Surface Laptop 7 machines, based on X1E80100.
>>
>> The feature status is mostly on par with other X Elite machines,
>> notably lacking:
>>
>> - USB-A and probably USB-over-Surface-connector
>> - SD card reader (Realtek RTS5261 connected over PCIe)
>> - Touchscreen and touchpad support (hid-over-SPI [1])
>> - Keyboard support (low-hanging fruit, works with pending Surface EC
>>   changes)
>> - Audio (a quick look suggests the setup is very close to the one in
>>   X1E CRD)
>>
>> The two Surface Laptop 7 SKUs (13.8" and 15") only have very minor
>> differences, amounting close to none on the software side. Even the
>> MBN firmware files and ACPI tables are shared between the two machines.
>>
>> With that in mind, support is added for both, although only the larger
>> one was physically tested. Display differences will be taken care of
>> through fused-in EDID and other matters should be solved within the
>> EC and boot firmware.
>>
>> [1] https://www.microsoft.com/en-us/download/details.aspx?id=103325
>>
>> Signed-off-by: Konrad Dybcio <quic_kdybcio@...cinc.com>
>> ---

[...]

>> +	backlight: backlight {
>> +		compatible = "pwm-backlight";
>> +		pwms = <&pmk8550_pwm 0 5000000>;
>> +		enable-gpios = <&pmc8380_3_gpios 4 GPIO_ACTIVE_HIGH>;
>> +		/* TODO: power-supply? */
> 
> There seems to be something at <&pmc8380_3_gpios 10>, any idea what?

Yeah I looked at it, but switching it hi/lo made absolutely no difference

> 
>> [...]
>> +&pmk8550_gpios {
>> +	edp_bl_pwm: edp-bl-pwm-state {
>> +		pins = "gpio5";
>> +		function = "func3";
> 
> Can you add the power-source here to make this more complete?

The bootloader leaves it with power-source = <1>, I'll add it..

> 
>> +	};
>> +
>> [...]
>> +
>> +&uart2 {
>> +	status = "okay";
>> +};
> 
> Any idea what this UART is used for?

The EC :) Since I believe the required patches will get in promptly,
(and had to tear down my tree into something submittable), I didn't
add a comment here..

> 
>> [...]
>> diff --git a/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi b/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
>> index a5ca0fa4e5ae..5b54ee79f048 100644
>> --- a/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/x1e80100-pmics.dtsi
>> @@ -249,6 +249,14 @@ pmk8550_gpios: gpio@...0 {
>>  			interrupt-controller;
>>  			#interrupt-cells = <2>;
>>  		};
>> +
>> +		pmk8550_pwm: pwm {
>> +			compatible = "qcom,pmk8550-pwm";
>> +
>> +			#pwm-cells = <2>;
>> +
>> +			status = "disabled";
>> +		};
> 
> I don't mind personally but usually we would have this non-device
> addition in a separate patch. :-)

Yeah I can do that

Konrad