MT-149180: add basic ipc/extcon mechanism to send usb events from the stm through the kernel

Documentation/devicetree/bindings/extcon/multitracks,stm32-spi-ipc.yaml

@@ -0,0 +1,95 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/extcon/multitracks,stm32-spi-ipc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MultiTracks STM32 SPI IPC USB extcon provider
+
+maintainers:
+  - Samuel Morris <scmorris.dev@gmail.com>
+
+description: |
+  An SPI client that talks to an external STM32 co-processor. The STM32 reports
+  USB cable/role events (disconnected, peripheral or host) for each physical USB
+  port over SPI, signalled by a dedicated attention (interrupt) line.
+
+  Each USB port is described by a child connector node that acts as an extcon
+  provider (EXTCON_USB / EXTCON_USB_HOST) for the USB OTG controller wired to
+  that port, allowing it to switch between host and peripheral roles.
+
+properties:
+  compatible:
+    const: multitracks,stm32-spi-ipc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+    description:
+      Attention line, driven by the STM32 co-processor to signal that a new
+      event packet is pending on the SPI bus.
+
+patternProperties:
+  '^connector-usb[0-9]+$':
+    type: object
+    description:
+      A virtual USB connector exposed as an extcon provider. Reference it from
+      the "extcon" property of the corresponding USB OTG controller node.
+
+    properties:
+      compatible:
+        const: multitracks,stm32-usb-connector
+
+      port-id:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        maximum: 255
+        description:
+          Identifier of the USB port on the STM32 co-processor that this
+          connector represents. It is matched against the "port" field of the
+          incoming SPI event packet.
+
+    required:
+      - compatible
+      - port-id
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ipc@0 {
+            compatible = "multitracks,stm32-spi-ipc";
+            reg = <0>;
+            spi-max-frequency = <10000000>;
+            interrupt-parent = <&gpio2>;
+            interrupts = <11 IRQ_TYPE_EDGE_FALLING>;
+
+            connector-usb1 {
+                compatible = "multitracks,stm32-usb-connector";
+                port-id = <0>;
+            };
+
+            connector-usb2 {
+                compatible = "multitracks,stm32-usb-connector";
+                port-id = <1>;
+            };
+        };
+    };
+...

arch/arm64/boot/dts/freescale/mt-connect.dts

@@ -495,15 +495,29 @@
 };
 
 &ecspi2 {
-	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <0>;
 	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_ecspi2>;
+	pinctrl-0 = <&pinctrl_ecspi2 &pinctrl_stm_ipc>;
 	cs-gpios = <&gpio5 13 GPIO_ACTIVE_LOW>;
+	status = "okay";
 
-	spidev1: spi@0 {
+	stm_ipc: stm32-ipc@0 {
+		compatible = "multitracks,stm32-spi-ipc";
 		reg = <0>;
-		compatible = "rohm,dh2228fv";
-		spi-max-frequency = <500000>;
+		spi-max-frequency = <10000000>;
+		interrupt-parent = <&gpio4>;
+		interrupts = <29 IRQ_TYPE_EDGE_FALLING>;
+
+		usb1_connector: connector-usb1 {
+			compatible = "multitracks,stm32-usb-connector";
+			port-id = <0>;
+		};
+
+		usb2_connector: connector-usb2 {
+			compatible = "multitracks,stm32-usb-connector";
+			port-id = <1>;
+		};
 	};
 };
 
@@ -520,6 +534,14 @@
 };
 
 &usbotg1 {
+	/*
+	 * ChipIdea reads extcon phandle 0 as the VBUS (EXTCON_USB) source and
+	 * phandle 1 as the ID (EXTCON_USB_HOST) source. The connector provides
+	 * both cable types, so point both indices at it; otherwise the ID/host
+	 * notifier is never registered by ci_extcon_register() and host-role
+	 * events are dropped.
+	 */
+	extcon = <&usb1_connector>, <&usb1_connector>;
 	hnp-disable;
 	srp-disable;
 	adp-disable;
@@ -533,6 +555,8 @@
 };
 
 &usbotg2 {
+	/* Both extcon indices point at the connector; see &usbotg1. */
+	extcon = <&usb2_connector>, <&usb2_connector>;
 	hnp-disable;
 	srp-disable;
 	adp-disable;
@@ -710,9 +734,9 @@
 		>;
 	};
 
-	pinctrl_typec1: typec1grp {
+	pinctrl_stm_ipc: stmipcgrp {
 		fsl,pins = <
-		MX8MM_IOMUXC_SD1_STROBE_GPIO2_IO11			0x159
+		MX8MM_IOMUXC_SAI3_RXC_GPIO4_IO29			0x82 /* STM IPC attention (ECSPI2 INT) */
 		>;
 	};
 
@@ -735,9 +759,7 @@
 		MX8MM_IOMUXC_ECSPI2_MISO_ECSPI2_MISO		0x82
 		MX8MM_IOMUXC_ECSPI2_MOSI_ECSPI2_MOSI		0x82
 		MX8MM_IOMUXC_ECSPI2_SCLK_ECSPI2_SCLK		0x82
-		MX8MM_IOMUXC_ECSPI2_SS0_ECSPI2_SS0			0x82
-		MX8MM_IOMUXC_ECSPI2_SS0_GPIO5_IO13			0x140 /* ECSPI2 NSS */
-		MX8MM_IOMUXC_SAI3_RXC_GPIO4_IO29			0x82 /* ECSPI2 INT */
+		MX8MM_IOMUXC_ECSPI2_SS0_GPIO5_IO13			0x140 /* ECSPI2 NSS (cs-gpios) */
 		>;
 	};
 

arch/arm64/configs/mt_connect_defconfig

@@ -654,6 +654,7 @@ CONFIG_FSL_QIXIS=y
 CONFIG_SOC_TI=y
 CONFIG_EXTCON_PTN5150=m
 CONFIG_EXTCON_USB_GPIO=y
+CONFIG_EXTCON_STM32_SPI_IPC=y
 CONFIG_IIO=y
 CONFIG_FXLS8962AF_I2C=m
 CONFIG_IIO_ST_ACCEL_3AXIS=m

drivers/extcon/Kconfig

@@ -176,6 +176,15 @@ config EXTCON_USB_GPIO
 	  Say Y here to enable GPIO based USB cable detection extcon support.
 	  Used typically if GPIO is used for USB ID pin detection.
 
+config EXTCON_STM32_SPI_IPC
+	tristate "STM32 SPI IPC and Virtual Extcon support"
+	depends on SPI && OF
+	select CRC8
+	help
+	  Say Y here to enable the STM32 SPI IPC and Virtual Extcon driver,
+	  which handles USB connection/cable event notifications reported
+	  by an external STM32 co-processor over SPI.
+
 config EXTCON_USBC_CROS_EC
 	tristate "ChromeOS Embedded Controller EXTCON support"
 	depends on CROS_EC

drivers/extcon/Makefile

@@ -23,5 +23,6 @@ obj-$(CONFIG_EXTCON_QCOM_SPMI_MISC) += extcon-qcom-spmi-misc.o
 obj-$(CONFIG_EXTCON_RT8973A)	+= extcon-rt8973a.o
 obj-$(CONFIG_EXTCON_SM5502)	+= extcon-sm5502.o
 obj-$(CONFIG_EXTCON_USB_GPIO)	+= extcon-usb-gpio.o
+obj-$(CONFIG_EXTCON_STM32_SPI_IPC)	+= extcon-stm32-ipc.o
 obj-$(CONFIG_EXTCON_USBC_CROS_EC) += extcon-usbc-cros-ec.o
 obj-$(CONFIG_EXTCON_USBC_TUSB320) += extcon-usbc-tusb320.o