linux-kernel - Re: [PATCH 2/2] arm64: dts: qcom: sm8650: Add support for Oneplus Pad Pro (caihong)

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Message-ID: <408e79e9-4998-4b5c-b378-bd61eda85882@linaro.org>
Date: Mon, 26 May 2025 09:53:42 +0200
From: neil.armstrong@...aro.org
To: Pengyu Luo <mitltlatltl@...il.com>
Cc: andersson@...nel.org, conor+dt@...nel.org, devicetree@...r.kernel.org,
 konrad.dybcio@....qualcomm.com, konradybcio@...nel.org, krzk+dt@...nel.org,
 linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, robh@...nel.org
Subject: Re: [PATCH 2/2] arm64: dts: qcom: sm8650: Add support for Oneplus Pad
 Pro (caihong)

On 22/05/2025 12:05, Pengyu Luo wrote:
> On Wed, May 21, 2025 at 8:43 PM <neil.armstrong@...aro.org> wrote:
>> On 21/05/2025 10:37, Pengyu Luo wrote:
>>> On Wed, May 21, 2025 at 5:54 AM Konrad Dybcio <konrad.dybcio@....qualcomm.com> wrote:
>>>> On 5/20/25 6:42 PM, Pengyu Luo wrote:
>>>>> The OnePlus Pad Pro is an Android tablet based on the Qualcomm SM8650
>>>>> platform. Its device codename is "caihong". This patch adds an initial
>>>>> devicetree for basic functionality.
>>>>>
>>>>> Currently working components include:
>>>>> - Backlight
>>>>> - Bluetooth
>>>>> - Battery charging (up to 5v 0.5a) & reporting via pmic-glink (There
>>>>> are many unknown notifications)
>>>>> - Display panel ([1])
>>>>> - Keyboard (via BT)
>>>>> - Power key & volume keys
>>>>> - Touchscreen & stylus ([2])
>>>>> - USB Type-c port
>>>>> - UFS storage
>>>>> - Wi-Fi
>>>>>
>>>>> The following components are currently non-functional:
>>>>> - Audio
>>>>> - Cameras
>>>>> - Charging pump (dual sc8547)
>>>>> - Keyboard (via pogo pin)
>>>>> - Stylus wireless charger (cps8601)
>>>>> - UCSI over GLINK (PPM init fails)
>>>>>
>>>>> [1]: The panel is a dual-DSI, dual-DSC display that requires setting
>>>>>        'slice_per_pkt = 2' in the DPU configuration. The panel driver
>>>>>        will be submitted separately later.
>>>>> [2]: Touchscreen/stylus driver available at:
>>>>>        https://github.com/OnePlusOSS/android_kernel_modules_and_devicetree_oneplus_sm8650/blob/oneplus/sm8650_v_15.0.0_pad_pro/vendor/oplus/kernel/touchpanel/oplus_touchscreen_v2/Novatek/NT36532_noflash/nvt_drivers_nt36532_noflash.c
>>>>>        The downstream driver has been ported and tested locally, but
>>>>>        requires cleanup, it may be submitted separately later.
>>>>
>>>> I have a Lenovo Tab P11 with a nt36523w (-23, not -32) for which I have once
>>>> poked at the driver for.. I see the driver you posted mentions -23 as well,
>>>> please keep me in the loop if you're going to upstream it
>>>>
>>>
>>> I see. Actually, they share the most part of nt36xxx, but with
>>> different memory maps. See
>>> https://github.com/MiCode/Xiaomi_Kernel_OpenSource/blob/elish-r-oss/drivers/input/touchscreen/nt36xxx/nt36xxx_mem_map.h
>>>
>>>> [...]
>>>>
>>>>> +             /*
>>>>> +              * This memory region is required to initialize the backlight
>>>>> +              * and display for bootloader. Normally, this region is not
>>>>> +              * needed. However, due to limitations in the current mainline
>>>>> +              * KTZ8866 driver, dual backlight ICs cannot be properly
>>>>> +              * initialized.
>>>>> +              *
>>>>> +              * A workaround involving secondary registration was proposed,
>>>>> +              * but rejected by reviewers. This reserved region is kept as
>>>>> +              * a temporary solution until a proper initialization method
>>>>> +              * that satisfies upstream requirements is found.
>>>>> +              */
>>>>> +             splash_region {
>>>>> +                     reg = <0 0xd5100000 0 0x2b00000>;
>>>>> +                     no-map;
>>>>> +             };
>>>>
>>>> I assume this means "if the bootloader sees /reserved-memory/splash_region,
>>>> it keeps the display online" - let's not do that, as underscores are not
>>>> allowed in node names (kernel coding style, not dt syntax)
>>>>
>>>
>>> Right, without it, BL won't initialize backlight and display. We need
>>> it to initialize backlight here since mainline ktz8866 won't program
>>> partial registers properly. If there is no other workaround, I will
>>> remove it to keep kernel coding style.
>>
>> Can't you add a simple-framebuffer for v1 and drop all the DSI stuff until
>> you figured out the backlight and upstreamed the panel driver ?
>>
> 
> I am thinking about it. But still, if backlight can't be properly
> programmed, simple-framebuffer won't help.

Sure but with this version you have simply have no display at all,
so just drop the backlight + dsi stuff for initial patchset, then
when you figured out the backlight and the panel driver update the DT.

Neil

> 
> Best wishes,
> Pengyu