References: <20211217125757.1193256-1-balbi@kernel.org>
 <20211217125757.1193256-3-balbi@kernel.org>
 <e2ed8317-a656-f6ac-9fc5-810588f33105@somainline.org>
User-agent: mu4e 1.6.10; emacs 28.0.90
From:   Felipe Balbi <balbi@kernel.org>
To:     Konrad Dybcio <konrad.dybcio@somainline.org>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC/patch 2/2] arm64: boot: dts: qcom: surface duo: add
 minimal framebuffer
Date:   Sat, 18 Dec 2021 09:19:07 +0200
In-reply-to: <e2ed8317-a656-f6ac-9fc5-810588f33105@somainline.org>
Message-ID: <878rwi4bwt.fsf@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk


Hi,

Konrad Dybcio <konrad.dybcio@somainline.org> writes:

> On 17.12.2021 13:57, Felipe Balbi wrote:
>> From: Felipe Balbi <felipe.balbi@microsoft.com>
>>
>> Add a minimal framebuffer device so we can use the display on the
>> Surface Duo device.
>>
>> Signed-off-by: Felipe Balbi <felipe.balbi@microsoft.com>
>> ---
>>  .../dts/qcom/sm8150-microsoft-surface-duo.dts | 19 +++++++++++++++++++
>>  1 file changed, 19 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/sm8150-microsoft-surface-duo.dts b/arch/arm64/boot/dts/qcom/sm8150-microsoft-surface-duo.dts
>> index a73317e1a824..c629ec115fec 100644
>> --- a/arch/arm64/boot/dts/qcom/sm8150-microsoft-surface-duo.dts
>> +++ b/arch/arm64/boot/dts/qcom/sm8150-microsoft-surface-duo.dts
>> @@ -25,6 +25,17 @@ chosen {
>>  		stdout-path = "serial0:115200n8";
>>  	};
>>  
>> +	framebuffer0: framebuffer@9c000000 {
>> +		compatible = "simple-framebuffer";
>> +		reg = <0 0x9c000000 0 0x02400000>;
>
> You can remove the leading 0 in the size cell.

okay

>> +		status = "okay";
>
> This line is unnecessary, as it's enabled by default

understood

>> @@ -472,6 +483,14 @@ &pon_resin {
>>  	linux,code = <KEY_VOLUMEDOWN>;
>>  };
>>  
>> +&reserved_memory {
>> +	splash_region: splash_region@9c000000 {
>> +		/* We expect the bootloader to fill in the size */
>
> Would it be different than the framebuffer size?

honestly, I used this mainly to get the correct base address and size. I
had 0 everywhere and bootloader filled the entire thing for me. I can
just hardcode with the expected values anyway.

-- 
balbi