From 091fad7c15290d2102255bd98bef6cede9eff731 Mon Sep 17 00:00:00 2001 From: Wei Deng Date: Thu, 7 May 2026 12:53:20 +0530 Subject: [PATCH] WORKAROUND: arm64: dts: qcom: purwa-iot-evk: support Bluetooth over both USB and UART On Purwa boards, a single M.2 slot may host either a UART-based or a USB-based Bluetooth device. As a result, the UART controller node is always present in DT, while the USB path is hot-pluggable. When Bluetooth operates over USB, the presence of the UART DT node still causes the hci_qca UART driver to probe. During probe or power sequencing, the driver may deassert BT_EN, cutting power to the shared Bluetooth device and disconnecting the USB interface. Model BT_EN as an always-on fixed regulator so it cannot be toggled by the UART probe. This prevents the UART driver from interfering with Bluetooth operation when the device is connected over USB. Workaround will be reverted once the M.2 solutionis available upstream. Signed-off-by: Wei Deng --- arch/arm64/boot/dts/qcom/purwa-iot-evk.dts | 34 ++++++++++++++++------ 1 file changed, 25 insertions(+), 9 deletions(-) diff --git a/arch/arm64/boot/dts/qcom/purwa-iot-evk.dts b/arch/arm64/boot/dts/qcom/purwa-iot-evk.dts index ad503beec1d3d..c39081b064b10 100644 --- a/arch/arm64/boot/dts/qcom/purwa-iot-evk.dts +++ b/arch/arm64/boot/dts/qcom/purwa-iot-evk.dts @@ -514,6 +514,23 @@ regulator-boot-on; }; + vreg_wcn_bt_en: regulator-wcn-bt-en { + compatible = "regulator-fixed"; + + regulator-name = "VREG_WCN_BT_EN"; + regulator-min-microvolt = <1800000>; + regulator-max-microvolt = <1800000>; + + gpio = <&tlmm 116 GPIO_ACTIVE_HIGH>; + enable-active-high; + + pinctrl-0 = <&wcn_bt_en>; + pinctrl-names = "default"; + + regulator-always-on; + regulator-boot-on; + }; + vreg_wwan: regulator-wwan { compatible = "regulator-fixed"; @@ -628,10 +645,9 @@ vddrfa1p2-supply = <&vreg_wcn_1p9>; vddrfa1p8-supply = <&vreg_wcn_1p9>; - bt-enable-gpios = <&tlmm 116 GPIO_ACTIVE_HIGH>; wlan-enable-gpios = <&tlmm 117 GPIO_ACTIVE_HIGH>; - pinctrl-0 = <&wcn_bt_en>, <&wcn_wlan_en>; + pinctrl-0 = <&wcn_wlan_en>; pinctrl-names = "default"; regulators { @@ -1504,13 +1520,13 @@ compatible = "qcom,wcn7850-bt"; max-speed = <3200000>; - vddaon-supply = <&vreg_pmu_aon_0p59>; - vddwlcx-supply = <&vreg_pmu_wlcx_0p8>; - vddwlmx-supply = <&vreg_pmu_wlmx_0p85>; - vddrfacmn-supply = <&vreg_pmu_rfa_cmn>; - vddrfa0p8-supply = <&vreg_pmu_rfa_0p8>; - vddrfa1p2-supply = <&vreg_pmu_rfa_1p2>; - vddrfa1p8-supply = <&vreg_pmu_rfa_1p8>; + vddaon-supply = <&vreg_wcn_3p3>; + vddwlcx-supply = <&vreg_wcn_3p3>; + vddwlmx-supply = <&vreg_wcn_3p3>; + vddrfacmn-supply = <&vreg_wcn_3p3>; + vddrfa0p8-supply = <&vreg_wcn_3p3>; + vddrfa1p2-supply = <&vreg_wcn_3p3>; + vddrfa1p8-supply = <&vreg_wcn_3p3>; }; };