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

[Rahul Samana]

The reworked RB3 Gen 2 Industrial mezzanine keeps the common Industrial
mezzanine hardware description but routes QCC2072 Bluetooth over UART4
instead of the default Bluetooth-over-USB path.

Build this variant by applying the common Industrial mezzanine overlay
first, followed by the BT UART overlay. The overlay models the M.2 E-key
connector graph endpoints for PCIe and UART, and disables the on-board
WCN6750 PMU and UART7 path so the M.2 QCC2072 Bluetooth controller can be
used instead.

Signed-off-by: Rahul Samana <rahul.samana@xxxxxxxxxxxxxxxx>
---
 arch/arm64/boot/dts/qcom/Makefile                  |   2 +
 ...s6490-rb3gen2-industrial-mezzanine-bt-uart.dtso | 129 +++++++++++++++++++++
 2 files changed, 131 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/Makefile b/arch/arm64/boot/dts/qcom/Makefile
index 6f33c4e2f09c..45786d3db14a 100644
--- a/arch/arm64/boot/dts/qcom/Makefile
+++ b/arch/arm64/boot/dts/qcom/Makefile
@@ -179,8 +179,10 @@ dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2.dtb
 
 qcs6490-rb3gen2-vision-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-vision-mezzanine.dtbo
 qcs6490-rb3gen2-industrial-mezzanine-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-industrial-mezzanine.dtbo
+qcs6490-rb3gen2-industrial-mezzanine-bt-uart-dtbs := qcs6490-rb3gen2.dtb qcs6490-rb3gen2-industrial-mezzanine.dtbo qcs6490-rb3gen2-industrial-mezzanine-bt-uart.dtbo
 
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2-industrial-mezzanine.dtb
+dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2-industrial-mezzanine-bt-uart.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-rb3gen2-vision-mezzanine.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-thundercomm-minipc-g1iot.dtb
 dtb-$(CONFIG_ARCH_QCOM)	+= qcs6490-thundercomm-rubikpi3.dtb
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 000000000000..67577d6f279f
--- /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>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				m2_e_pcie_ep: endpoint@0 {
+					reg = <0>;
+					remote-endpoint = <&pcie0_m2_e_ep>;
+				};
+			};
+
+			port@3 {
+				reg = <3>;
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				m2_e_uart_ep: endpoint@0 {
+					reg = <0>;
+					remote-endpoint = <&uart4_m2_e_ep>;
+				};
+			};
+		};
+	};
+};
+
+&qup_uart4_cts {
+	bias-bus-hold;
+};
+
+&qup_uart4_rts {
+	drive-strength = <2>;
+	bias-disable;
+};
+
+&qup_uart4_rx {
+	bias-pull-up;
+};
+
+&qup_uart4_tx {
+	drive-strength = <2>;
+	bias-disable;
+};
+
+&tlmm {
+	qup_uart4_sleep_cts: qup-uart4-sleep-cts-state {
+		pins = "gpio16";
+		function = "gpio";
+		bias-bus-hold;
+	};
+
+	qup_uart4_sleep_rts: qup-uart4-sleep-rts-state {
+		pins = "gpio17";
+		function = "gpio";
+		bias-pull-down;
+	};
+
+	qup_uart4_sleep_tx: qup-uart4-sleep-tx-state {
+		pins = "gpio18";
+		function = "gpio";
+		bias-pull-up;
+	};
+
+	qup_uart4_sleep_rx: qup-uart4-sleep-rx-state {
+		pins = "gpio19";
+		function = "gpio";
+		bias-pull-up;
+	};
+};
+
+&pcie0_m2_e {
+	port {
+		pcie0_m2_e_ep: endpoint {
+			remote-endpoint = <&m2_e_pcie_ep>;
+		};
+	};
+};
+
+&uart4 {
+	interrupts-extended = <&intc GIC_SPI 605 IRQ_TYPE_LEVEL_HIGH>,
+			      <&tlmm 19 IRQ_TYPE_EDGE_FALLING>;
+	pinctrl-names = "default", "sleep";
+	pinctrl-1 = <&qup_uart4_sleep_cts>, <&qup_uart4_sleep_rts>,
+		    <&qup_uart4_sleep_tx>, <&qup_uart4_sleep_rx>;
+
+	status = "okay";
+
+	port {
+		uart4_m2_e_ep: endpoint {
+			remote-endpoint = <&m2_e_uart_ep>;
+		};
+	};
+};
+
+&uart7 {
+	status = "disabled";
+};
+
+&wcn6750_pmu {
+	status = "disabled";
+};

-- 
2.34.1