Re: [PATCH] arm64: dts: qcom: Split sdm845-db845c to add headless support

[Krzysztof Kozlowski]

On 05/06/2023 11:47, Amit Pundir wrote:
> This is a follow-up of the upstream discussion,
> https://lore.kernel.org/linux-kernel/20230124182857.1524912-1-amit.pundir@xxxxxxxxxx/T/#u,
> around adding a reserved memory region in sdm845-db845c
> for the framebuffer memory (the splash region set up by
> the bootloader) but the general opinion was to avoid
> adding that reserved memory for the headless DB845c
> usecase.
> 
> So this patch splits the sdm845-db845c into a common dtsi,
> a new sdm845-db845-headless DT, which disables the mdss
> display subsystem, and a new sdm845-db845c DT with an
> additional reserved-memory region for the framebuffer.
> 
> The default sdm845-db845c.dtb remains pretty much the same
> (with an exception of additional reserved-memory region),
> while others can use sdm845-db845c-headless.dtb for their
> headless systems.

You should describe the hardware in commit msg. What is "headless"? If
no HDMI plugged in, then it is a NAK because plug or unplugged HDMI
cable is not a property of a DTS.

> 
> Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
> ---
> Please pick this after the lvs regulator nodes reordering patch
> https://lore.kernel.org/lkml/20230602161246.1855448-1-amit.pundir@xxxxxxxxxx/T/#u.
> I'll rebase and resend this patch otherwise.
> 
>  arch/arm64/boot/dts/qcom/Makefile             |    1 +
>  .../boot/dts/qcom/sdm845-db845c-common.dtsi   | 1178 +++++++++++++++++
>  .../boot/dts/qcom/sdm845-db845c-headless.dts  |    9 +
>  arch/arm64/boot/dts/qcom/sdm845-db845c.dts    | 1172 +---------------

A lot of duplication. Are you sure you generated the patches with
correct -M/-C/-B arguments to rename or copy?

>  4 files changed, 1194 insertions(+), 1166 deletions(-)
>  create mode 100644 arch/arm64/boot/dts/qcom/sdm845-db845c-common.dtsi
>  create mode 100644 arch/arm64/boot/dts/qcom/sdm845-db845c-headless.dts
> 
> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
> index 4f9e81253e18..22876ea2e409 100644
> --- a/arch/arm64/boot/dts/qcom/Makefile
> +++ b/arch/arm64/boot/dts/qcom/Makefile
> @@ -166,6 +166,7 @@ dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-cheza-r1.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-cheza-r2.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-cheza-r3.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-db845c.dtb
> +dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-db845c-headless.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-db845c-navigation-mezzanine.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-lg-judyln.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= sdm845-lg-judyp.dtb
> diff --git a/arch/arm64/boot/dts/qcom/sdm845-db845c-common.dtsi b/arch/arm64/boot/dts/qcom/sdm845-db845c-common.dtsi
> new file mode 100644
> index 000000000000..ecc4a851e29c
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/sdm845-db845c-common.dtsi
> @@ -0,0 +1,1178 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Linaro Ltd.
> + */
> +
> +/dts-v1/;
> +
> +#include <dt-bindings/leds/common.h>
> +#include <dt-bindings/pinctrl/qcom,pmic-gpio.h>
> +#include <dt-bindings/regulator/qcom,rpmh-regulator.h>
> +#include <dt-bindings/sound/qcom,q6afe.h>
> +#include <dt-bindings/sound/qcom,q6asm.h>
> +#include "sdm845.dtsi"
> +#include "sdm845-wcd9340.dtsi"
> +#include "pm8998.dtsi"
> +#include "pmi8998.dtsi"
> +
> +/ {
> +	model = "Thundercomm Dragonboard 845c";
> +	compatible = "thundercomm,db845c", "qcom,sdm845";

So it is the same hardware? Why compatible is in common part? I don't
understand this change.

Best regards,
Krzysztof