Re: [PATCH v3 9/9] board: qualcomm: Add support for QCS404 EVB

[Stephan Gerhold <stephan@gerhold.net>]

Hi Sumit,

On Tue, Jul 12, 2022 at 12:42:12PM +0530, Sumit Garg wrote:
> Add support for Qualcomm QCS404 SoC based evaluation board.
> 
> Features:
> - Qualcomm Snapdragon QCS404 SoC
> - 1GiB RAM
> - 8GiB eMMC, uSD slot
> 
> U-boot is chain loaded by ABL in 64-bit mode as part of boot.img.
> For detailed build and boot instructions, refer to
> doc/board/qualcomm/qcs404.rst.
> 
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
>  arch/arm/dts/Makefile                    |  1 +
>  arch/arm/dts/qcs404-evb-uboot.dtsi       | 24 +++++++
>  arch/arm/dts/qcs404-evb.dts              | 81 ++++++++++++++++++++++++
>  arch/arm/mach-snapdragon/Kconfig         | 11 ++++
>  arch/arm/mach-snapdragon/Makefile        |  2 +
>  arch/arm/mach-snapdragon/sysmap-qcs404.c | 31 +++++++++
>  board/qualcomm/qcs404-evb/Kconfig        | 15 +++++
>  board/qualcomm/qcs404-evb/MAINTAINERS    |  6 ++
>  board/qualcomm/qcs404-evb/Makefile       |  6 ++
>  board/qualcomm/qcs404-evb/qcs404-evb.c   | 33 ++++++++++
>  board/qualcomm/qcs404-evb/qcs404-evb.its | 64 +++++++++++++++++++
>  configs/qcs404evb_defconfig              | 39 ++++++++++++
>  doc/board/qualcomm/index.rst             |  1 +
>  doc/board/qualcomm/qcs404.rst            | 79 +++++++++++++++++++++++
>  include/configs/qcs404-evb.h             | 27 ++++++++
>  15 files changed, 420 insertions(+)
>  create mode 100644 arch/arm/dts/qcs404-evb-uboot.dtsi
>  create mode 100644 arch/arm/dts/qcs404-evb.dts
>  create mode 100644 arch/arm/mach-snapdragon/sysmap-qcs404.c
>  create mode 100644 board/qualcomm/qcs404-evb/Kconfig
>  create mode 100644 board/qualcomm/qcs404-evb/MAINTAINERS
>  create mode 100644 board/qualcomm/qcs404-evb/Makefile
>  create mode 100644 board/qualcomm/qcs404-evb/qcs404-evb.c
>  create mode 100644 board/qualcomm/qcs404-evb/qcs404-evb.its
>  create mode 100644 configs/qcs404evb_defconfig
>  create mode 100644 doc/board/qualcomm/qcs404.rst
>  create mode 100644 include/configs/qcs404-evb.h
> 
> [...]
> diff --git a/arch/arm/dts/qcs404-evb.dts b/arch/arm/dts/qcs404-evb.dts
> new file mode 100644
> index 0000000000..4f0ae20bdb
> --- /dev/null
> +++ b/arch/arm/dts/qcs404-evb.dts
> @@ -0,0 +1,81 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Qualcomm QCS404 based evaluation board device tree source
> + *
> + * (C) Copyright 2022 Sumit Garg <sumit.garg@linaro.org>
> + */
> +
> +/dts-v1/;
> +
> +#include "skeleton64.dtsi"
> +#include <dt-bindings/gpio/gpio.h>
> +#include <dt-bindings/pinctrl/pinctrl-snapdragon.h>
> +#include <dt-bindings/clock/qcom,gcc-qcs404.h>
> +
> +/ {
> +	model = "Qualcomm Technologies, Inc. QCS404 EVB";
> +	compatible = "qcom,qcs404-evb", "qcom,qcs404";
> +	#address-cells = <0x2>;
> +	#size-cells = <0x2>;
> +
> +	chosen {
> +		stdout-path = "serial0:115200n8";
> +	};
> +
> +	aliases {
> +		serial0 = &debug_uart;
> +	};
> +
> +	memory {
> +		device_type = "memory";
> +		reg = <0 0x80000000 0 0x40000000>;
> +	};
> +
> +	soc {
> +		#address-cells = <0x1>;
> +		#size-cells = <0x1>;
> +		ranges = <0x0 0x0 0x0 0xffffffff>;
> +		compatible = "simple-bus";
> +
> +		pinctrl_north@1300000 {
> +			compatible = "qcom,tlmm-qcs404";
> +			reg = <0x1300000 0x200000>;
> +
> +			blsp1_uart2: uart {
> +				pins = "GPIO_17", "GPIO_18";
> +				function = "blsp_uart2";
> +			};
> +		};
> +

I know you're just following the example of the existing Qualcomm boards
here but I think we should really avoid adding any more custom device
trees that are inconsistent with the official (upstream) Linux bindings.

Many other boards in U-Boot have moved to using the upstream Linux DTs
as-is (with some additions in -u-boot.dtsi) and I think we should do the
same for the Qualcomm boards. Judging from Tom's comments on other
patches (e.g. [1]), this might even be a requirement now?

The SPMI fix I just sent for DB410c/DB820c [2] is a good example why it
is important to have bindings consistent with Linux. Looking at your
patch reminded me that I never sent this fix (thanks!).

Can you check how hard it would be to reuse the upstream QCS404 DT?

Thanks!
Stephan

[1]: https://lore.kernel.org/u-boot/20220601152800.GJ25375@bill-the-cat/
[2]: https://lore.kernel.org/u-boot/20220713191711.4155-1-stephan@gerhold.net/