[PATCH v4 5/9] dt-bindings: connector: Add PCIe M.2 Mechanical Key E connector

Manivannan Sadhasivam via B4 Relay
2026-01-12T16:28:33Z

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Add the devicetree binding for PCIe M.2 Mechanical Key E connector defined
in the PCI Express M.2 Specification, r4.0, sec 5.1.2. This connector
provides interfaces like PCIe or SDIO to attach the WiFi devices to the
host machine, USB or UART+PCM interfaces to attach the Bluetooth (BT)
devices. Spec also provides an optional interface to connect the UIM card,
but that is not covered in this binding.

The connector provides a primary power supply of 3.3v, along with an
optional 1.8v VIO supply for the Adapter I/O buffer circuitry operating at
1.8v sideband signaling.

The connector also supplies optional signals in the form of GPIOs for fine
grained power management.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
.../bindings/connector/pcie-m2-e-connector.yaml | 154 +++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 155 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
new file mode 100644
index 000000000000..b65b39ddfd19
--- /dev/null
+++ b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
@@ -0,0 +1,154 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/connector/pcie-m2-e-connector.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PCIe M.2 Mechanical Key E Connector
+
+maintainers:
+ - Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
+
+description:
+ A PCIe M.2 E connector node represents a physical PCIe M.2 Mechanical Key E
+ connector. Mechanical Key E connectors are used to connect Wireless
+ Connectivity devices including combinations of Wi-Fi, BT, NFC to the host
+ machine over interfaces like PCIe/SDIO, USB/UART+PCM, and I2C.
+
+properties:
+ compatible:
+ const: pcie-m2-e-connector
+
+ vpcie3v3-supply:
+ description: A phandle to the regulator for 3.3v supply.
+
+ vpcie1v8-supply:
+ description: A phandle to the regulator for VIO 1.8v supply.
+
+ ports:
+ $ref: /schemas/graph.yaml#/properties/ports
+ description: OF graph bindings modeling the interfaces exposed on the
+ connector. Since a single connector can have multiple interfaces, every
+ interface has an assigned OF graph port number as described below.
+
+ properties:
+ port@0:
+ $ref: /schemas/graph.yaml#/properties/port
+ description: Connector interfaces for Wi-Fi
+
+ properties:
+ endpoint@0:
+ $ref: /schemas/graph.yaml#/properties/endpoint
+ description: PCIe interface
+
+ endpoint@1:
+ $ref: /schemas/graph.yaml#/properties/endpoint
+ description: SDIO interface
+
+ anyOf:
+ - required:
+ - endpoint@0
+ - required:
+ - endpoint@1
+
+ port@1:
+ $ref: /schemas/graph.yaml#/properties/port
+ description: Connector interfaces for BT
+
+ properties:
+ endpoint@0:
+ $ref: /schemas/graph.yaml#/properties/endpoint
+ description: USB 2.0 interface
+
+ endpoint@1:
+ $ref: /schemas/graph.yaml#/properties/endpoint
+ description: UART interface
+
+ anyOf:
+ - required:
+ - endpoint@0
+ - required:
+ - endpoint@1
+
+ port@2:
+ $ref: /schemas/graph.yaml#/properties/port
+ description: PCM/I2S interface
+
+ i2c-parent:
+ $ref: /schemas/types.yaml#/definitions/phandle
+ description: I2C interface
+
+ oneOf:
+ - required:
+ - port@0
+
+ clocks:
+ description: 32.768 KHz Suspend Clock (SUSCLK) input from the host system to
+ the M.2 card. Refer, PCI Express M.2 Specification r4.0, sec 3.1.12.1 for
+ more details.
+ maxItems: 1
+
+ w-disable1-gpios:
+ description: GPIO input to W_DISABLE1# signal. This signal is used by the
+ system to disable WiFi radio in the M.2 card. Refer, PCI Express M.2
+ Specification r4.0, sec 3.1.12.3 for more details.
+ maxItems: 1
+
+ w-disable2-gpios:
+ description: GPIO input to W_DISABLE2# signal. This signal is used by the
+ system to disable WiFi radio in the M.2 card. Refer, PCI Express M.2
+ Specification r4.0, sec 3.1.12.3 for more details.
+ maxItems: 1
+
+ viocfg-gpios:
+ description: GPIO output to IO voltage configuration (VIO_CFG) signal. This
+ signal is used by the M.2 card to indicate to the host system that the
+ card supports an independent IO voltage domain for the sideband signals.
+ Refer, PCI Express M.2 Specification r4.0, sec 3.1.15.1 for more details.
+ maxItems: 1
+
+required:
+ - compatible
+ - vpcie3v3-supply
+
+additionalProperties: false
+
+examples:
+ # PCI M.2 Key E connector for Wi-Fi/BT with PCIe/UART interfaces
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+
+ connector {
+ compatible = "pcie-m2-e-connector";
+ vpcie3v3-supply = <&vreg_wcn_3p3>;
+ vpcie1v8-supply = <&vreg_l15b_1p8>;
+ w-disable1-gpios = <&tlmm 117 GPIO_ACTIVE_LOW>;
+ w-disable2-gpios = <&tlmm 116 GPIO_ACTIVE_LOW>;
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 {
+ reg = <0>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ endpoint@0 {
+ reg = <0>;
+ remote-endpoint = <&pcie4_port0_ep>;
+ };
+ };
+
+ port@1 {
+ reg = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ endpoint@1 {
+ reg = <1>;
+ remote-endpoint = <&uart14_ep>;
+ };
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2eb7b6d26573..451c54675b24 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20795,6 +20795,7 @@ PCIE M.2 POWER SEQUENCING
M: Manivannan Sadhasivam <mani@kernel.org>
L: linux-pci@vger.kernel.org
S: Maintained
+F: Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
F: Documentation/devicetree/bindings/connector/pcie-m2-m-connector.yaml
F: drivers/power/sequencing/pwrseq-pcie-m2.c

--
2.48.1