Re: [PATCH v2 6/6] arm64: dts: qcom: rb3gen2: add Industrial BT UART overlay

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] The overlay fails to delete the existing default PCIe child node (`usb-controller@0,0`) under the M.2 E-key slot (`&pcie0_m2_e`), causing a devfn collision and erroneous OF node binding.
- [High] The `m2-e-connector` node uses a dummy, uncontrolled regulator for the 3.3V supply rather than the actual GPIO-controlled rail powering the slot.
- [Medium] Missing `/delete-property/ interrupts;` when adding `interrupts-extended` to `&uart4`.
--

--- Patch [6]: [PATCH v2 6/6] arm64: dts: qcom: rb3gen2: add Industrial BT UART overlay ---
commit 978523089bf29d9bf8d8d86680d9cc1d3d558116
Author: Rahul Samana <rahul.samana@oss.qualcomm.com>

arm64: dts: qcom: rb3gen2: add Industrial BT UART overlay

The reworked RB3 Gen 2 Industrial mezzanine routes QCC2072 Bluetooth over
UART4 instead of the default Bluetooth-over-USB path. This patch adds a new
overlay that models the M.2 E-key connector graph endpoints for PCIe and UART,
and disables the on-board WCN6750 PMU and UART7 path.

> diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-bt-uart.dtso b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-bt-uart.dtso
> new file mode 100644
> index 0000000000000..67577d6f279f4
> --- /dev/null
> +++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2-industrial-mezzanine-bt-uart.dtso
> @@ -0,0 +1,129 @@
> +// SPDX-License-Identifier: BSD-3-Clause
> +/*
> + * Copyright (c) 2026 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +#include <dt-bindings/gpio/gpio.h>
> +#include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +&{/} {
> +	vreg_wcn_3p3: regulator-wcn-3p3 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "VREG_WCN_3P3";
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +
> +		regulator-boot-on;
> +	};
> +
> +	m2-e-connector {
> +		compatible = "pcie-m2-e-connector";
> +		vpcie3v3-supply = <&vreg_wcn_3p3>;

[Severity: High]
Does this dummy regulator break hardware power sequencing for the M.2 slot?

The base board's M.2 E-key slot is powered by the vreg_pcie0_3p3 regulator
(controlled by PMIC GPIO 1), but this assigns a dummy vreg_wcn_3p3 fixed
regulator with no GPIO hardware control. This could cause the power sequencing
driver to blindly toggle a software dummy state instead of the actual hardware
power rail.

Should this use vpcie3v3-supply = <&vreg_pcie0_3p3>; and drop the dummy
vreg_wcn_3p3 definition so the power sequencing logic works properly?

[ ... ]

> +&pcie0_m2_e {
> +	port {
> +		pcie0_m2_e_ep: endpoint {
> +			remote-endpoint = <&m2_e_pcie_ep>;
> +		};
> +	};
> +};

[Severity: High]
Does this overlay need to delete the existing default usb-controller@0,0 child
node from the base board's pcie0_m2_e slot?

Since the QCC2072 PCI device enumerates dynamically on this slot, it will share
the same bus address. The PCI subsystem might incorrectly assign the
usb-controller@0,0 DT node to the Wi-Fi device, which would apply the USB
controller's default pinctrl and regulator dependencies to the Wi-Fi card,
leading to hardware state corruption.

Can this be resolved by adding a /delete-node/ usb-controller@0,0; under
&pcie0_m2_e?

> +
> +&uart4 {
> +	interrupts-extended = <&intc GIC_SPI 605 IRQ_TYPE_LEVEL_HIGH>,
> +			      <&tlmm 19 IRQ_TYPE_EDGE_FALLING>;

[Severity: Medium]
Does this node also need to explicitly delete the inherited interrupts property?

The &uart4 node inherits the interrupts property from the base SoC devicetree.
Adding interrupts-extended without a /delete-property/ interrupts; results in
both properties being present, which violates DT schema and causes dtbs_check
validation warnings.

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260727-rb3-industrial-bt-uart-v2-0-2d100f30e202@oss.qualcomm.com?part=6