Add Embedded USB Debugger (EUD) driver

This is a series of patches that implements a driver for the control peripheral, EUD (Embedded USB Debugger). The EUD is a mini-USB hub implemented on chip to support the USB-based debug and trace capabilities. Apart from debug capabilities, EUD has a control peripheral. Control Peripheral is on when EUD is on and gets signals like USB attach, pet EUD etc. EUD driver listens to events like USB attach or detach and then informs the USB about these events via ROLE-SWITCH. At regular intervals, the EUD driver receives an interrupt to pet the driver indicating that the software is functional.

Changes in V1

* EUD has now been mapped as a separate DT node as it is an independent QCOM IP.

* EUD is attached to the connector child of dwc3 via port end point since EUD driver needs the connector for role-switching,

* EUD driver has been moved now to drivers/soc/qcom/qcom_eud.c.

* All the comments from version 0 of the patch has been implemented.

Souradeep Chowdhury (8):
dt-bindings: Add the yaml bindings for EUD
dt-bindings: connector: Add property for EUD type-C connector
bindings: usb: dwc3: Update dwc3 properties for EUD connector
usb: dwc3: drd: Register the eud connector child node for dwc3
soc: qcom: eud: Add driver support for Embedded USB Debugger(EUD)
arm64: dts: qcom: sc7280: Add EUD dt node and dwc3 connector
arm64: dts: qcom: sc7280: Set the default dr_mode for usb2
MAINTAINERS: Add maintainer entry for EUD

 Documentation/ABI/testing/sysfs-driver-eud         |   9 +
 .../bindings/connector/usb-connector.yaml          |   4 +
 .../devicetree/bindings/soc/qcom/qcom,eud.yaml     |  52 ++++
 .../devicetree/bindings/usb/snps,dwc3.yaml         |   6 +
 MAINTAINERS                                        |   8 +
 arch/arm64/boot/dts/qcom/sc7280-idp.dts            |   4 +
 arch/arm64/boot/dts/qcom/sc7280.dtsi               |  25 ++
 drivers/soc/qcom/Kconfig                           |  10 +
 drivers/soc/qcom/Makefile                          |   1 +
 drivers/soc/qcom/qcom_eud.c                        | 268 +++++++++++++++++++++
 drivers/usb/dwc3/drd.c                             |  26 ++
 11 files changed, 413 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-eud
 create mode 100644 Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
 create mode 100644 drivers/soc/qcom/qcom_eud.c

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

Documentation for Embedded USB Debugger(EUD) device tree bindings in yaml format.

---
 .../devicetree/bindings/soc/qcom/qcom,eud.yaml     | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml

new file mode 100644
index 0000000..724552c
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/soc/qcom/qcom,eud.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Qualcomm Embedded USB Debugger
+
+maintainers:
+  - Souradeep Chowdhury <[email protected]>
+
+description: |
+  This binding is used to describe the Qualcomm Embedded USB Debugger, which is
+  mini USB-hub implemented on chip to support USB-based debug capabilities.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,sc7280-eud
+      - const: qcom,eud
+
+  reg:
+    items:
+      - description: EUD Base Register Region
+      - description: EUD Mode Manager Register
+
+  interrupts:
+    description:
+      EUD interrupt
+
+
+  port:
+    description:
+      Any connector to the data bus of this controller should be modelled
+      using the OF graph bindings specified, if the "usb-role-switch"
+      property is used. See graph.txt
+    $ref: /schemas/graph.yaml#/properties/port
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    eud@88e0000 {
+           compatible = "qcom,sc7280-eud","qcom,eud";
+           reg = <0 0x88e0000 0 0x2000>,
+                 <0 0x88e2000 0 0x1000>;
+    };

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check' on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/soc/qcom/qcom,eud.example.dt.yaml: example-0: eud@88e0000:reg:0: [0, 143523840, 0, 8192] is too long
From schema: /usr/local/lib/python3.8/dist-packages/dtschema/schemas/reg.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/soc/qcom/qcom,eud.example.dt.yaml: example-0: eud@88e0000:reg:1: [0, 143532032, 0, 4096] is too long
From schema: /usr/local/lib/python3.8/dist-packages/dtschema/schemas/reg.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1558347

This check can fail if there are any dependencies. The base for a patch series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date:

pip3 install dtschema --upgrade

Please check and re-submit.

Ack

Ack

The end point of this port is attached to the connector child of dwc3 node. The dwc3 node has the "usb-role-switch" property. So "usb-role-switch" is not a valid property of the EUD node.
Will update the description with more clarity accordingly.

Ack

Added the property for EUD(Embedded USB Debugger) connector. EUD is a mini usb hub with debug and trace capabilities and it has a type C connector attached to it for role-switching. This connector is attached to EUD via port.

---
 Documentation/devicetree/bindings/connector/usb-connector.yaml | 4 ++++
 1 file changed, 4 insertions(+)

index 7eb8659..bd1823a 100644
@@ -30,6 +30,10 @@ properties:
           - const: samsung,usb-connector-11pin
           - const: usb-b-connector
 
+      - items:
+          - const: qcom,usb-connector-eud
+          - const: usb-c-connector
+
   label:
     description: Symbolic name for the connector.
 

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Add the connector property for dwc3 node. This connector can be used to role-switch the controller from device to host and vice versa.

---
 Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

index 078fb78..9382168 100644
@@ -318,6 +318,12 @@ properties:
     items:
       enum: [1, 4, 8, 16, 32, 64, 128, 256]
 
+  connector:
+    type: object
+    $ref: /connector/usb-connector.yaml#
+    description:
+      Connector for dual role switch, especially for "eud-usb-c-connector"
+
 unevaluatedProperties: false
 
 required:

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Register the child node for dwc3 which is the "eud_usb_connector". The eud driver will be able to switch the usb role from device to host and vice versa using the role switch property of dwc3 node.

---
 drivers/usb/dwc3/drd.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

index d7f7683..b4ea55c 100644
@@ -8,6 +8,7 @@
  */
 
 #include <linux/extcon.h>
+#include <linux/of_platform.h>
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>

@@ -164,6 +165,27 @@ static int dwc3_otg_get_irq(struct dwc3 *dwc)
 	return irq;
 }
 
+static int dwc3_register_eud(struct dwc3 *dwc)
+{
+	struct device		*dev = dwc->dev;
+	struct device_node	*np = dev->of_node;
+	int                     ret;
+
+	of_get_child_by_name(np, "eud_usb_connector");
+	if (!np) {
+		dev_dbg(dev, "no usb_connector child node specified\n");
+		return 0;
+	}
+
+	ret = of_platform_populate(np, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "failed to register usb_connector - %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 void dwc3_otg_init(struct dwc3 *dwc)
 {
 	u32 reg;

@@ -580,6 +602,10 @@ int dwc3_drd_init(struct dwc3 *dwc)
 		ret = dwc3_setup_role_switch(dwc);
 		if (ret < 0)
 			return ret;
+
+		ret = dwc3_register_eud(dwc);
+		if (ret < 0)
+			return ret;
 	} else if (dwc->edev) {
 		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
 		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Add support for control peripheral of EUD (Embedded USB Debugger) to listen to events such as USB attach/detach, pet EUD to indicate software is functional.Reusing the platform device kobj, sysfs entry 'enable' is created to enable or disable EUD.

To enable the eud the following needs to be done
echo 1 > /sys/bus/platform/.../enable

To disable eud, following is the command
echo 0 > /sys/bus/platform/.../enable

---
 Documentation/ABI/testing/sysfs-driver-eud |   9 +
 drivers/soc/qcom/Kconfig                   |  10 ++
 drivers/soc/qcom/Makefile                  |   1 +
 drivers/soc/qcom/qcom_eud.c                | 268 +++++++++++++++++++++++++++++
 4 files changed, 288 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-eud
 create mode 100644 drivers/soc/qcom/qcom_eud.c

new file mode 100644
index 0000000..eaf2e82
@@ -0,0 +1,9 @@
+What:		/sys/bus/platform/drivers/eud/.../enable
+Date:           October 2021
+Contact:        Souradeep Chowdhury <[email protected]>
+Description:
+		The Enable/Disable sysfs interface for Embedded
+		USB Debugger(EUD). This enables and disables the
+		EUD based on a 1 or a 0 value. By enabling EUD,
+		the user is able to activate the mini-usb hub of
+		EUD for debug and trace capabilities.

index 79b568f..a4db41b 100644
@@ -42,6 +42,16 @@ config QCOM_CPR
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-cpr
 
+config QCOM_EUD
+	tristate "QCOM Embedded USB Debugger(EUD) Driver"
+	select USB_ROLE_SWITCH
+	help
+	  This module enables support for Qualcomm Technologies, Inc.
+	  Embedded USB Debugger (EUD). The EUD is a control peripheral
+	  which reports VBUS attach/detach events and has USB-based
+	  debug and trace capabilities. On selecting m, the module name
+	  that is built is qcom_eud.ko
+
 config QCOM_GENI_SE
 	tristate "QCOM GENI Serial Engine Driver"
 	depends on ARCH_QCOM || COMPILE_TEST

index ad675a6..3331a40 100644
@@ -4,6 +4,7 @@ obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
 obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
 obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
 obj-$(CONFIG_QCOM_CPR)		+= cpr.o
+obj-$(CONFIG_QCOM_EUD)          += qcom_eud.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Add the Embedded USB Debugger(EUD) device tree node. The node contains EUD base register region and EUD mode manager register regions along with the interrupt entry. Also add the connector to EUD which is mapped as the child of dwc3. The connector is attached to EUD via port. Also add the role-switch property to dwc3 node.

---
 arch/arm64/boot/dts/qcom/sc7280.dtsi | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

index 53a21d0..2d14e5c 100644
@@ -1315,6 +1315,18 @@
 				phys = <&usb_2_hsphy>;
 				phy-names = "usb2-phy";
 				maximum-speed = "high-speed";
+				usb-role-switch;
+				usb_con: eud_usb_connector {
+					compatible = "qcom,usb-connector-eud",
+						     "usb-c-connector";
+					ports {
+						port@0 {
+							usb2_role_switch: endpoint {
+								remote-endpoint = <&eud_ep>;
+							};
+						};
+					};
+				};
 			};
 		};
 

@@ -1339,6 +1351,19 @@
 			interrupts = <GIC_SPI 582 IRQ_TYPE_LEVEL_HIGH>;
 		};
 
+		eud:  eud@88e0000 {
+			compatible = "qcom,sc7280-eud","qcom,eud";
+			reg = <0 0x88e0000 0 0x2000>,
+			      <0 0x88e2000 0 0x1000>;
+			interrupt-parent = <&pdc>;
+			interrupts = <11 IRQ_TYPE_LEVEL_HIGH>;
+			port {
+				eud_ep: endpoint {
+					remote-endpoint = <&usb2_role_switch>;
+				};
+			};
+		};
+
 		nsp_noc: interconnect@a0c0000 {
 			reg = <0 0x0a0c0000 0 0x10000>;
 			compatible = "qcom,sc7280-nsp-noc";

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Set the default dr_mode for usb2 node to "otg" to enable. role-switch for EUD(Embedded USB Debugger) connector node.

---
 arch/arm64/boot/dts/qcom/sc7280-idp.dts | 4 ++++
 1 file changed, 4 insertions(+)

index 64fc22a..7c69c78 100644
@@ -61,6 +61,10 @@
 	modem-init;
 };
 
+&usb_2_dwc3 {
+	dr_mode = "otg";
+};
+
 &pmk8350_vadc {
 	pmr735a_die_temp {
 		reg = <PMR735A_ADC7_DIE_TEMP>;

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Add the entry for maintainer for EUD driver
and other associated files.

---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

index 0227e15..54f616a 100644
@@ -7018,6 +7018,14 @@ F:	include/trace/events/mdio.h
 F:	include/uapi/linux/mdio.h
 F:	include/uapi/linux/mii.h
 
+EUD-QCOM
+M:	Souradeep Chowdhury <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	Documentation/ABI/testing/sysfs-driver-eud
+F:	Documentation/devicetree/bindings/arm/msm/qcom,eud.yaml
+F:	drivers/usb/common/qcom_eud.c
+
 EXFAT FILE SYSTEM
 M:	Namjae Jeon <[email protected]>
 M:	Sungjong Seo <[email protected]>

QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation