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

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Message-ID: <20250522100526.914341-1-mitltlatltl@gmail.com>
Date: Thu, 22 May 2025 18:05:24 +0800
From: Pengyu Luo <mitltlatltl@...il.com>
To: neil.armstrong@...aro.org
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,
	mitltlatltl@...il.com,
	robh@...nel.org
Subject: Re: [PATCH 2/2] arm64: dts: qcom: sm8650: Add support for Oneplus Pad Pro (caihong)

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.

Best wishes,
Pengyu