Re: [PATCH v2 1/1] arm64: dts: qcom: monaco-evk: Add Interface Plus Mezzanine

[Krzysztof Kozlowski <krzk@kernel.org>]

On 22/02/2026 18:35, Umang Chheda wrote:
> The Interface Plus [IFP] Mezzanine is an hardware expansion add-on
> board designed to be stacked on top of Monaco EVK.
> 
> It has following peripherals :
> 
> - 4x Type A USB ports in host mode.
> - TC9563 PCIe switch, which has following three downstream ports (DSP) :
>    - 1st DSP connects M.2 E-key connector for connecting WLAN endpoints.
>    - 2nd DSP connects M.2 B-key connector for connecting cellular
>      modems.
>    - 3rd DSP with support for Dual Ethernet ports.
> - EEPROM.
> - LVDS Display.
> - 2*mini DP.
> 
> Add support for following peripherals :
> - TC9563 PCIe Switch.
> - EEPROM.
> 
> Written with inputs from :
>     Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> - PCIe
>     Monish Chunara <monish.chunara@oss.qualcomm.com> - EEPROM.
> 
> Signed-off-by: Umang Chheda <umang.chheda@oss.qualcomm.com>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>  arch/arm64/boot/dts/qcom/Makefile             |   4 +
>  .../dts/qcom/monaco-evk-ifp-mezzanine.dtso    | 184 ++++++++++++++++++
>  2 files changed, 188 insertions(+)
>  create mode 100644 arch/arm64/boot/dts/qcom/monaco-evk-ifp-mezzanine.dtso
> 
> diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
> index f80b5d9cf1e8..9d298e7e8a90 100644
> --- a/arch/arm64/boot/dts/qcom/Makefile
> +++ b/arch/arm64/boot/dts/qcom/Makefile
> @@ -45,6 +45,10 @@ lemans-evk-el2-dtbs := lemans-evk.dtb lemans-el2.dtbo
>  dtb-$(CONFIG_ARCH_QCOM)	+= lemans-evk-el2.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= milos-fairphone-fp6.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= monaco-evk.dtb
> +
> +monaco-evk-ifp-mezzanine-dtbs	:= monaco-evk.dtb monaco-evk-ifp-mezzanine.dtbo
> +
> +dtb-$(CONFIG_ARCH_QCOM)	+= monaco-evk-ifp-mezzanine.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= msm8216-samsung-fortuna3g.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-acer-a1-724.dtb
>  dtb-$(CONFIG_ARCH_QCOM)	+= msm8916-alcatel-idol347.dtb
> diff --git a/arch/arm64/boot/dts/qcom/monaco-evk-ifp-mezzanine.dtso b/arch/arm64/boot/dts/qcom/monaco-evk-ifp-mezzanine.dtso
> new file mode 100644
> index 000000000000..f0572647200c
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/monaco-evk-ifp-mezzanine.dtso
> @@ -0,0 +1,184 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +#include <dt-bindings/gpio/gpio.h>
> +
> +&{/} {
> +	model = "Qualcomm Technologies, Inc. Monaco-EVK IFP Mezzanine";
> +
> +	vreg_0p9: regulator-vreg-0p9 {

Please use name for all fixed regulators which matches current format
recommendation: 'regulator-[0-9]v[0-9]'

https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml

Duplicating regulator name (regulator-reg(ulator)) is pointless.

> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_0P9";
> +
> +		regulator-min-microvolt = <900000>;
> +		regulator-max-microvolt = <900000>;
> +		regulator-always-on;
> +		regulator-boot-on;
> +
> +		vin-supply = <&vreg_3p3>;
> +	};
> +
> +	vreg_1p8: regulator-vreg-1p8 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_1P8";
> +
> +		regulator-min-microvolt = <1800000>;
> +		regulator-max-microvolt = <1800000>;
> +		regulator-always-on;
> +		regulator-boot-on;
> +
> +		vin-supply = <&vreg_4p2>;
> +	};
> +
> +	vreg_3p3: regulator-vreg-3p3 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_3P3";
> +
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +		regulator-always-on;
> +		regulator-boot-on;
> +
> +		vin-supply = <&vreg_4p2>;
> +	};
> +
> +	vreg_4p2: regulator-vreg-4p2 {

Unused node (other dummies don't really count).

> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_4P2";
> +
> +		regulator-min-microvolt = <4200000>;
> +		regulator-max-microvolt = <4200000>;
> +		regulator-always-on;
> +		regulator-boot-on;
> +
> +		vin-supply = <&vreg_sys_pwr>;
> +	};
> +
> +	vreg_sys_pwr: regulator-vreg-sys-pwr {

What is the point of this regulator? It is not used by anything (another
dummy is not considered an user).

> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_SYS_PWR";
> +
> +		regulator-min-microvolt = <24000000>;
> +		regulator-max-microvolt = <24000000>;
> +		regulator-always-on;
> +		regulator-boot-on;
> +	};
> +};
> +


Best regards,
Krzysztof