[PATCH v5 0/9] Improve Qualcomm EUD driver and platform support

[PATCH v5 0/9] Improve Qualcomm EUD driver and platform support

[Elson Serrao]

The Embedded USB Debugger (EUD) is a High-Speed USB on-chip hub that
provides debug and trace capabilities on Qualcomm platforms. The current
EUD driver, however, lacks essential hardware resources such as PHY
references and support for multi-port configurations. This series
addresses those gaps and introduces the necessary device tree updates
to enable testing and validation of the enhanced functionality.

Below is a high-level block diagram showing the EUD and its connections.


			              EUD Block
 	                   +------------------------------+  
			   |                              |
[Conn-0]-->[USB2PHY-0]---->|-------- Path 0 --------------|-->[USBCtrl-0]
			   |                              |  
[Conn-1]-->[USB2PHY-1]---->|-------- Path 1 --------------|-->[USBCtrl-1]
			   |                              |
			   |      +------------------+    |
			   |      |  EUD Debug Hub   |    |
			   |      +------------------+    |
			   +------------------------------+

The series has been validated on the Qualcomm Dragonwing Q6 platform
(RB3 Gen2 board), confirming successful OpenOCD connectivity to the EUD
interface. For detailed usage instructions, refer to Qualcomm’s Linux
kernel debugging guide:
https://docs.qualcomm.com/bundle/publicresource/topics/80-70020-12/debugging_linux_kernel.html#debug-using-openocd

Testing feedback:
 - Konrad Dybcio reported running a slightly modified version of this
   series on Agatti with no obvious issues:
   https://lore.kernel.org/all/8d4f10ef-602c-4e1e-9711-443a5f3fa7f3@oss.qualcomm.com/

---
Changes in v5:
 - [Patch 0001] Add a compatible for a SoC that supports EUD over two
   ports, restrict paths based on SoC hardware, and improve the commit
   message [Krzysztof/Dmitry]
 - [Patch 0002/0003] Document error codes in ABI doc.
 - [Patch 0004] Zero-initialize the USB role switch descriptor [Peter].
   Add a dr_mode check to handle cases where the USB controller
   operates in a fixed role without role-switch support (based on
   internal testing).
 - [Patch 0006] Drop eud_disabled_for_host flag and control EUD based on
   device role entry/exit [Peter]. Allow EUD to be powered on only in
   device role and defer enablement in other roles until the port
   switches to device role.
 - Link to v4: https://lore.kernel.org/all/20260501170635.2641748-1-elson.serrao@oss.qualcomm.com/

Changes in v4:
- [Patch 0001] Restructure the flattened ports representation to a child-node
  based model.
  - Preserve the top-level 'ports' property and add per-path child nodes,
    so that each role-switch path is described using its own OF graph.
    (Dmitry).
  - Link to the discussion leading to this design decision:
    https://lore.kernel.org/all/20260324172916.804229-1-elson.serrao@oss.qualcomm.com/
- [Patch 0002] Use explicit port names when selecting the active EUD
  port (Greg)
- [Patch 0003] Use a scoped iterator when looping over child nodes and
  drop redundant EUD path validation checks (Konrad). Preserve support
  for the legacy top-level ports description.
- [Patch 0004] Register role switch per path and forward the role switch
  notifications to the USB controller.
- [Patch 0006]  Add host mode co-ordination based on the role changes as
  per the new design and drop the custom API that was used to get role
  notifications.
- [Patch 0008] Described the UTMI path as a child node with role switch
  capability.
- Link to v3: https://lore.kernel.org/all/20260309203337.803986-1-elson.serrao@oss.qualcomm.com/

Changes in RFC v3:
- Replaced the per-path (eud-path@N) model with a flattened ports
  representation based on the feedback.
- Added port@2 and port@3 to support dual-port configurations.
- Removed the EUD-local 'phys' and 'usb-role-switch' properties since PHY
  and role-switch information is obtained from walking the OF graph.
- Updated PHY discovery logic by fetching the PHY from the controller
  node/fwnode, and exported a new API for the controller to report role
  changes. The dwc3-qcom driver now uses this API to notify EUD on role
  transitions.
- Updated the DTS structure by moving the EUD-to-controller port mapping
  into the base SoC DTSI, enabling EUD by default, and adjusting all board
  DTS files accordingly, including adding the usb-role-switch provider
  link on connector nodes.
- Link to v2: https://lore.kernel.org/all/20260126233830.2193816-1-elson.serrao@oss.qualcomm.com/

Changes in v2:
- Improved commit message of patch 0001 and 0003 with historical context
  on why EUD worked without PHY references on single-path systems.
  Expanded the usb-role-switch property description in the bindings file.
- Link to v1: https://lore.kernel.org/all/20260116232106.2234978-1-elson.serrao@oss.qualcomm.com/
---

Elson Serrao (9):
  dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing
  usb: misc: qcom_eud: add sysfs attribute for port selection
  usb: misc: qcom_eud: add per-path High-Speed PHY control
  usb: misc: qcom_eud: add per-path role switch support
  usb: misc: qcom_eud: improve enable_store API
  usb: misc: qcom_eud: add role-based EUD control
  usb: misc: qcom_eud: fix virtual attach/detach event handling
  arm64: dts: qcom: kodiak: Describe EUD UTMI path using child node
  arm64: dts: qcom: Map USB connector to EUD on Kodiak boards

 Documentation/ABI/testing/sysfs-driver-eud    |  19 +
 .../bindings/soc/qcom/qcom,eud.yaml           | 128 ++++++-
 arch/arm64/boot/dts/qcom/kodiak.dtsi          |  35 +-
 .../boot/dts/qcom/qcm6490-fairphone-fp5.dts   |  10 +-
 .../dts/qcom/qcm6490-particle-tachyon.dts     |  10 +-
 .../boot/dts/qcom/qcm6490-shift-otter.dts     |  10 +-
 arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts  |  10 +-
 .../qcom/qcs6490-thundercomm-minipc-g1iot.dts |   4 +-
 .../dts/qcom/qcs6490-thundercomm-rubikpi3.dts |  10 +-
 .../boot/dts/qcom/sm7325-motorola-dubai.dts   |   4 +-
 .../boot/dts/qcom/sm7325-nothing-spacewar.dts |  10 +-
 drivers/usb/misc/qcom_eud.c                   | 332 ++++++++++++++++--
 12 files changed, 513 insertions(+), 69 deletions(-)

-- 
2.34.1

[PATCH v5 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing

[Elson Serrao]

The Qualcomm Embedded USB Debugger (EUD) can intercept one or two
High-Speed UTMI paths depending on the SoC. For example, SC7280 supports
EUD on the primary UTMI path only, while SM8350 supports EUD on both
primary and secondary UTMI paths.

Each UTMI path connects an independent USB controller/connector pair and
forms its own role-switch domain. EUD routes traffic based on USB role.
In device role the debug hub is inserted, while in host role it is
bypassed.

The existing binding models EUD using a flattened ports representation.
While sufficient for fixed device-role configurations, it cannot naturally
associate a controller, connector, and role switch with a specific
EUD-routable path. This is problematic for role-switch capable ports and
becomes more pronounced on SoCs with multiple paths. In such cases, each
path forms an independent role-switch domain and requires per-path role
awareness.

Model each UTMI path as a separate child node with its own OF graph. Add
an SM8350 compatible for dual-path EUD topologies while retaining the
legacy ports representation for backward compatibility.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 .../bindings/soc/qcom/qcom,eud.yaml           | 128 +++++++++++++++++-
 1 file changed, 127 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
index 84218636c0d8..6fef958487c8 100644
--- a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
+++ b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
@@ -18,6 +18,7 @@ properties:
     items:
       - enum:
           - qcom,sc7280-eud
+          - qcom,sm8350-eud
       - const: qcom,eud
 
   reg:
@@ -45,10 +46,82 @@ properties:
         $ref: /schemas/graph.yaml#/properties/port
         description: This port is to be attached to the type C connector.
 
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^eud-path@[0-1]$":
+    type: object
+    description:
+      Represents one High-Speed UTMI path that EUD intercepts. Use eud-path nodes
+      to associate role-switching behavior with specific port connections, allowing
+      EUD to manage role transitions independently for each UTMI path.
+
+    properties:
+      reg:
+        maxItems: 1
+        description: Path number
+
+      usb-role-switch:
+        type: boolean
+        description:
+          Indicates that EUD relays USB role-switch events for this path and
+          performs role-dependent UTMI routing accordingly. In device role,
+          the EUD hub is inserted into this path to enable debug
+          functionality. In host role, the EUD hub is bypassed and UTMI
+          traffic flows directly between the PHY and the USB controller.
+
+      ports:
+        $ref: /schemas/graph.yaml#/properties/ports
+        description:
+          These ports are to be attached to the endpoint of the USB controller node
+          and USB connector node.
+
+        properties:
+          port@0:
+            $ref: /schemas/graph.yaml#/properties/port
+            description: This port is to be attached to the USB controller.
+
+          port@1:
+            $ref: /schemas/graph.yaml#/properties/port
+            description: This port is to be attached to the USB connector.
+
+    required:
+      - reg
+      - ports
+
+    additionalProperties: false
+
 required:
   - compatible
   - reg
-  - ports
+
+oneOf:
+  - required:
+      - ports
+  - allOf:
+      - if:
+          properties:
+            compatible:
+              contains:
+                const: qcom,sc7280-eud
+        then:
+          required:
+            - eud-path@0
+          properties:
+            eud-path@1: false
+      - if:
+          properties:
+            compatible:
+              contains:
+                const: qcom,sm8350-eud
+        then:
+          required:
+            - eud-path@0
+            - eud-path@1
 
 additionalProperties: false
 
@@ -77,3 +150,56 @@ examples:
             };
         };
     };
+  - |
+    eud@88e0000 {
+        compatible = "qcom,sm8350-eud", "qcom,eud";
+        reg = <0x88e0000 0x2000>,
+              <0x88e2000 0x1000>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        eud-path@0 {
+            reg = <0>;
+            usb-role-switch;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                port@0 {
+                    reg = <0>;
+                    eud_usb0: endpoint {
+                        remote-endpoint = <&usb_1_dwc3_hs>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    eud_con0: endpoint {
+                        remote-endpoint = <&pmic_glink_hs_in>;
+                    };
+                };
+            };
+        };
+
+        eud-path@1 {
+            reg = <1>;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                port@0 {
+                    reg = <0>;
+                    eud_usb1: endpoint {
+                        remote-endpoint = <&usb_2_dwc3_hs>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    eud_con1: endpoint {
+                        remote-endpoint = <&conn_2_hs_in>;
+                    };
+                };
+            };
+        };
+    };
-- 
2.34.1

[PATCH v5 2/9] usb: misc: qcom_eud: add sysfs attribute for port selection

[Elson Serrao]

EUD can be mapped to either the primary USB port or the secondary USB port
depending on the value of the EUD_PORT_SEL register. Add a 'port' sysfs
attribute to allow userspace to select which port EUD should operate on
and update the ABI documentation. This is needed for systems with dual
USB ports where EUD needs to be accessible on either port depending on the
system configuration and use case.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
Reviewed-by: Peter Chen <peter.chen@kernel.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
 Documentation/ABI/testing/sysfs-driver-eud | 18 ++++++++++
 drivers/usb/misc/qcom_eud.c                | 39 ++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-eud b/Documentation/ABI/testing/sysfs-driver-eud
index 2bab0db2d2f0..fb927a003596 100644
--- a/Documentation/ABI/testing/sysfs-driver-eud
+++ b/Documentation/ABI/testing/sysfs-driver-eud
@@ -7,3 +7,21 @@ Description:
 		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.
+
+What:		/sys/bus/platform/drivers/qcom_eud/.../port
+Date:		January 2026
+Contact:	Elson Serrao <elson.serrao@oss.qualcomm.com>
+Description:
+		Selects which USB port the Embedded USB Debugger (EUD)
+		is mapped to on platforms providing multiple High-Speed
+		USB ports.
+
+		Valid values:
+		  primary   - Primary USB port
+		  secondary - Secondary USB port
+
+		Writing any other value returns -EINVAL.
+
+		The attribute is writable only while EUD is disabled.
+		Writing it while EUD is enabled returns -EBUSY. Reading
+		the attribute returns the currently selected USB port.
diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index 926419ca560f..25a6a8f110ec 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -23,14 +23,22 @@
 #define EUD_REG_VBUS_INT_CLR	0x0080
 #define EUD_REG_CSR_EUD_EN	0x1014
 #define EUD_REG_SW_ATTACH_DET	0x1018
+#define EUD_REG_PORT_SEL	0x1028
 #define EUD_REG_EUD_EN2		0x0000
 
+#define EUD_MAX_PORTS		2
+
 #define EUD_ENABLE		BIT(0)
 #define EUD_INT_PET_EUD		BIT(0)
 #define EUD_INT_VBUS		BIT(2)
 #define EUD_INT_SAFE_MODE	BIT(4)
 #define EUD_INT_ALL		(EUD_INT_VBUS | EUD_INT_SAFE_MODE)
 
+static const char * const eud_port_names[] = {
+	"primary",
+	"secondary",
+};
+
 struct eud_chip {
 	struct device			*dev;
 	struct usb_role_switch		*role_sw;
@@ -40,6 +48,7 @@ struct eud_chip {
 	int				irq;
 	bool				enabled;
 	bool				usb_attached;
+	u8				port_idx;
 };
 
 static int enable_eud(struct eud_chip *priv)
@@ -104,8 +113,38 @@ static ssize_t enable_store(struct device *dev,
 
 static DEVICE_ATTR_RW(enable);
 
+static ssize_t port_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct eud_chip *chip = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%s\n", eud_port_names[chip->port_idx]);
+}
+
+static ssize_t port_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct eud_chip *chip = dev_get_drvdata(dev);
+	int port;
+
+	port = sysfs_match_string(eud_port_names, buf);
+	if (port < 0)
+		return port;
+
+	/* Port selection must be done before enabling EUD */
+	if (chip->enabled)
+		return -EBUSY;
+
+	writel(port, chip->base + EUD_REG_PORT_SEL);
+	chip->port_idx = port;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(port);
+
 static struct attribute *eud_attrs[] = {
 	&dev_attr_enable.attr,
+	&dev_attr_port.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(eud);
-- 
2.34.1

[PATCH v5 3/9] usb: misc: qcom_eud: add per-path High-Speed PHY control

[Elson Serrao]

EUD hardware can support multiple High-Speed USB paths, each routed
through its own PHY. The active path is selected in hardware via the
EUD_PORT_SEL register. As a High-Speed hub, EUD requires access to
the High-Speed PHY associated with the active path. To support this
multi-path capability, the driver must manage PHY resources on a
per-path basis, ensuring that the PHY for the currently selected
path is properly initialized and powered.

This patch restructures the driver to implement per-path PHY management.
The driver now powers the appropriate PHY based on the selected and
enabled UTMI path, ensuring correct operation when EUD is enabled.

Historically, EUD appeared to work on single-path systems because the
USB controller kept the PHY initialized. However, EUD is designed to
operate independently of the USB controller and therefore requires
explicit PHY control for proper operation.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
Reviewed-by: Peter Chen <peter.chen@kernel.org>
---
 Documentation/ABI/testing/sysfs-driver-eud |   3 +-
 drivers/usb/misc/qcom_eud.c                | 124 ++++++++++++++++++++-
 2 files changed, 125 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-eud b/Documentation/ABI/testing/sysfs-driver-eud
index fb927a003596..f20b82b5a38a 100644
--- a/Documentation/ABI/testing/sysfs-driver-eud
+++ b/Documentation/ABI/testing/sysfs-driver-eud
@@ -20,7 +20,8 @@ Description:
 		  primary   - Primary USB port
 		  secondary - Secondary USB port
 
-		Writing any other value returns -EINVAL.
+		Writing any other value returns -EINVAL. Writing a port
+		not supported on the current platform returns -EOPNOTSUPP.
 
 		The attribute is writable only while EUD is disabled.
 		Writing it while EUD is enabled returns -EBUSY. Reading
diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index 25a6a8f110ec..03d1c200658c 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -11,6 +11,8 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
@@ -39,26 +41,84 @@ static const char * const eud_port_names[] = {
 	"secondary",
 };
 
+struct eud_path {
+	struct eud_chip		*chip;
+	struct phy		*phy;
+	u8			num;
+};
+
 struct eud_chip {
 	struct device			*dev;
 	struct usb_role_switch		*role_sw;
 	void __iomem			*base;
+	struct eud_path			*paths[EUD_MAX_PORTS];
 	phys_addr_t			mode_mgr;
 	unsigned int			int_status;
 	int				irq;
 	bool				enabled;
 	bool				usb_attached;
+	bool				phy_enabled;
 	u8				port_idx;
 };
 
+static int eud_phy_enable(struct eud_chip *chip)
+{
+	struct phy *phy;
+	int ret;
+
+	if (chip->phy_enabled)
+		return 0;
+
+	phy = chip->paths[chip->port_idx]->phy;
+
+	ret = phy_init(phy);
+	if (ret) {
+		dev_err(chip->dev, "Failed to initialize USB2 PHY for port %u: %d\n",
+			chip->port_idx, ret);
+		return ret;
+	}
+
+	ret = phy_power_on(phy);
+	if (ret) {
+		dev_err(chip->dev, "Failed to power on USB2 PHY for port %u: %d\n",
+			chip->port_idx, ret);
+		phy_exit(phy);
+		return ret;
+	}
+
+	chip->phy_enabled = true;
+
+	return 0;
+}
+
+static void eud_phy_disable(struct eud_chip *chip)
+{
+	struct phy *phy;
+
+	if (!chip->phy_enabled)
+		return;
+
+	phy = chip->paths[chip->port_idx]->phy;
+
+	phy_power_off(phy);
+	phy_exit(phy);
+	chip->phy_enabled = false;
+}
+
 static int enable_eud(struct eud_chip *priv)
 {
 	int ret;
 
-	ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 1);
+	ret = eud_phy_enable(priv);
 	if (ret)
 		return ret;
 
+	ret = qcom_scm_io_writel(priv->mode_mgr + EUD_REG_EUD_EN2, 1);
+	if (ret) {
+		eud_phy_disable(priv);
+		return ret;
+	}
+
 	writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN);
 	writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
 			priv->base + EUD_REG_INT1_EN_MASK);
@@ -75,6 +135,8 @@ static int disable_eud(struct eud_chip *priv)
 		return ret;
 
 	writel(0, priv->base + EUD_REG_CSR_EUD_EN);
+	eud_phy_disable(priv);
+
 	return 0;
 }
 
@@ -130,6 +192,10 @@ static ssize_t port_store(struct device *dev, struct device_attribute *attr,
 	if (port < 0)
 		return port;
 
+	/* Check if the corresponding path is available */
+	if (!chip->paths[port])
+		return -EOPNOTSUPP;
+
 	/* Port selection must be done before enabling EUD */
 	if (chip->enabled)
 		return -EBUSY;
@@ -227,8 +293,54 @@ static void eud_role_switch_release(void *data)
 	usb_role_switch_put(chip->role_sw);
 }
 
+static int eud_init_path(struct eud_chip *chip, struct device_node *np)
+{
+	struct device_node *controller_node;
+	struct eud_path *path;
+	u32 path_num;
+	int ret;
+
+	ret = of_property_read_u32(np, "reg", &path_num);
+	if (ret) {
+		/* Legacy DT uses 'ports' node without 'reg' property; treat as path 0 */
+		if (of_node_name_eq(np, "ports"))
+			path_num = 0;
+		else
+			return dev_err_probe(chip->dev, ret, "unexpected child node '%s'\n",
+					     np->name);
+	}
+
+	if (path_num >= EUD_MAX_PORTS)
+		return dev_err_probe(chip->dev, -EINVAL, "invalid path number: %u (max %d)\n",
+				     path_num, EUD_MAX_PORTS - 1);
+
+	path = devm_kzalloc(chip->dev, sizeof(*path), GFP_KERNEL);
+	if (!path)
+		return -ENOMEM;
+
+	path->chip = chip;
+	path->num = path_num;
+
+	controller_node = of_graph_get_remote_node(np, 0, -1);
+	if (!controller_node)
+		return dev_err_probe(chip->dev, -ENODEV,
+				     "failed to get controller node for path %u\n", path_num);
+
+	path->phy = devm_of_phy_get_by_index(chip->dev, controller_node, 0);
+	of_node_put(controller_node);
+
+	if (IS_ERR(path->phy))
+		return dev_err_probe(chip->dev, PTR_ERR(path->phy),
+				     "failed to get PHY for path %d\n", path_num);
+
+	chip->paths[path_num] = path;
+
+	return 0;
+}
+
 static int eud_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct eud_chip *chip;
 	struct resource *res;
 	int ret;
@@ -239,6 +351,16 @@ static int eud_probe(struct platform_device *pdev)
 
 	chip->dev = &pdev->dev;
 
+	for_each_child_of_node_scoped(np, child) {
+		ret = eud_init_path(chip, child);
+		if (ret)
+			return ret;
+	}
+
+	/* Primary path is mandatory. Secondary is optional */
+	if (!chip->paths[0])
+		return dev_err_probe(chip->dev, -ENODEV, "primary path not found\n");
+
 	chip->role_sw = usb_role_switch_get(&pdev->dev);
 	if (IS_ERR(chip->role_sw))
 		return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
-- 
2.34.1

[PATCH v5 4/9] usb: misc: qcom_eud: add per-path role switch support

[Elson Serrao]

The EUD hardware can support multiple High-Speed USB paths, each connected
to different USB controllers. The current implementation uses a single
chip-level role switch, which cannot properly handle multi-path
configurations where each path needs independent role management. Since
EUD is physically present between the USB connector and the controller,
it should also relay the role change requests from the connector.

Restructure the driver to support per-path role switches and remove the
chip-level role switch. Additionally, as EUD need not modify the USB
role upon enabling, remove the unnecessary role switch call from
enable_eud().

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 drivers/usb/misc/qcom_eud.c | 100 +++++++++++++++++++++++++++++-------
 1 file changed, 81 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index 03d1c200658c..48a4441b0c9c 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -44,12 +44,15 @@ static const char * const eud_port_names[] = {
 struct eud_path {
 	struct eud_chip		*chip;
 	struct phy		*phy;
+	struct usb_role_switch	*controller_sw;
+	struct usb_role_switch	*eud_sw;
+	enum usb_role		curr_role;
+	char			name[16];
 	u8			num;
 };
 
 struct eud_chip {
 	struct device			*dev;
-	struct usb_role_switch		*role_sw;
 	void __iomem			*base;
 	struct eud_path			*paths[EUD_MAX_PORTS];
 	phys_addr_t			mode_mgr;
@@ -123,7 +126,7 @@ static int enable_eud(struct eud_chip *priv)
 	writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
 			priv->base + EUD_REG_INT1_EN_MASK);
 
-	return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
+	return 0;
 }
 
 static int disable_eud(struct eud_chip *priv)
@@ -270,12 +273,15 @@ static irqreturn_t handle_eud_irq(int irq, void *data)
 static irqreturn_t handle_eud_irq_thread(int irq, void *data)
 {
 	struct eud_chip *chip = data;
+	struct eud_path *path;
 	int ret;
 
+	path = chip->paths[chip->port_idx];
+
 	if (chip->usb_attached)
-		ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
+		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_DEVICE);
 	else
-		ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
+		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_HOST);
 	if (ret)
 		dev_err(chip->dev, "failed to set role switch\n");
 
@@ -286,17 +292,39 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static void eud_role_switch_release(void *data)
+static int eud_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
 {
-	struct eud_chip *chip = data;
+	struct eud_path *path = usb_role_switch_get_drvdata(sw);
+	int ret;
+
+	/* Forward the role request to the USB controller */
+	ret = usb_role_switch_set_role(path->controller_sw, role);
+	if (ret) {
+		dev_err(path->chip->dev, "failed to set role %s for port %u: %d\n",
+			usb_role_string(role), path->num, ret);
+		return ret;
+	}
+
+	path->curr_role = role;
 
-	usb_role_switch_put(chip->role_sw);
+	return 0;
+}
+
+static void eud_path_role_switch_release(void *data)
+{
+	struct eud_path *path = data;
+
+	usb_role_switch_unregister(path->eud_sw);
+	usb_role_switch_put(path->controller_sw);
 }
 
 static int eud_init_path(struct eud_chip *chip, struct device_node *np)
 {
+	struct usb_role_switch_desc role_sw_desc = {NULL};
+	struct usb_role_switch *sw;
 	struct device_node *controller_node;
 	struct eud_path *path;
+	const char *dr_mode = "";
 	u32 path_num;
 	int ret;
 
@@ -327,14 +355,57 @@ static int eud_init_path(struct eud_chip *chip, struct device_node *np)
 				     "failed to get controller node for path %u\n", path_num);
 
 	path->phy = devm_of_phy_get_by_index(chip->dev, controller_node, 0);
-	of_node_put(controller_node);
-
-	if (IS_ERR(path->phy))
+	if (IS_ERR(path->phy)) {
+		of_node_put(controller_node);
 		return dev_err_probe(chip->dev, PTR_ERR(path->phy),
 				     "failed to get PHY for path %d\n", path_num);
+	}
 
 	chip->paths[path_num] = path;
 
+	of_property_read_string(controller_node, "dr_mode", &dr_mode);
+
+	if (!strcmp(dr_mode, "host"))
+		path->curr_role = USB_ROLE_HOST;
+	else if (!strcmp(dr_mode, "peripheral"))
+		path->curr_role = USB_ROLE_DEVICE;
+	else
+		path->curr_role = USB_ROLE_NONE;
+
+	/* No role switch needed for fixed role controllers */
+	if (path->curr_role != USB_ROLE_NONE) {
+		of_node_put(controller_node);
+		return 0;
+	}
+
+	sw = usb_role_switch_find_by_fwnode(of_fwnode_handle(controller_node));
+	if (!sw) {
+		of_node_put(controller_node);
+		return dev_err_probe(chip->dev, -EPROBE_DEFER,
+				     "Failed to get controller role switch for path %d\n",
+				     path_num);
+	}
+	path->controller_sw = sw;
+
+	of_node_put(controller_node);
+
+	role_sw_desc.fwnode = of_fwnode_handle(np);
+	role_sw_desc.set = eud_role_switch_set;
+	role_sw_desc.driver_data = path;
+	snprintf(path->name, sizeof(path->name), "eud-path%u", path_num);
+	role_sw_desc.name = path->name;
+
+	path->eud_sw = usb_role_switch_register(chip->dev, &role_sw_desc);
+	if (IS_ERR(path->eud_sw)) {
+		usb_role_switch_put(path->controller_sw);
+		return dev_err_probe(chip->dev, PTR_ERR(path->eud_sw),
+				     "Failed to register EUD role switch for path %d\n", path_num);
+	}
+
+	ret = devm_add_action_or_reset(chip->dev, eud_path_role_switch_release, path);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
@@ -361,15 +432,6 @@ static int eud_probe(struct platform_device *pdev)
 	if (!chip->paths[0])
 		return dev_err_probe(chip->dev, -ENODEV, "primary path not found\n");
 
-	chip->role_sw = usb_role_switch_get(&pdev->dev);
-	if (IS_ERR(chip->role_sw))
-		return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
-					"failed to get role switch\n");
-
-	ret = devm_add_action_or_reset(chip->dev, eud_role_switch_release, chip);
-	if (ret)
-		return ret;
-
 	chip->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(chip->base))
 		return PTR_ERR(chip->base);
-- 
2.34.1

[PATCH v5 5/9] usb: misc: qcom_eud: improve enable_store API

[Elson Serrao]

Currently enable_store() allows operations irrespective of the EUD state,
which can result in redundant operations. Avoid this by adding duplicate
state checks to skip requests when EUD is already in the desired state.
Additionally, improve error handling with explicit logging to provide
better feedback.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Peter Chen <peter.chen@kernel.org>
---
 drivers/usb/misc/qcom_eud.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index 48a4441b0c9c..e83a4402e4b8 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -162,18 +162,27 @@ static ssize_t enable_store(struct device *dev,
 	if (kstrtobool(buf, &enable))
 		return -EINVAL;
 
+	/* Skip operation if already in desired state */
+	if (chip->enabled == enable)
+		return count;
+
 	if (enable) {
 		ret = enable_eud(chip);
-		if (!ret)
-			chip->enabled = enable;
-		else
-			disable_eud(chip);
-
+		if (ret) {
+			dev_err(chip->dev, "failed to enable eud\n");
+			return ret;
+		}
 	} else {
 		ret = disable_eud(chip);
+		if (ret) {
+			dev_err(chip->dev, "failed to disable eud\n");
+			return ret;
+		}
 	}
 
-	return ret < 0 ? ret : count;
+	chip->enabled = enable;
+
+	return count;
 }
 
 static DEVICE_ATTR_RW(enable);
-- 
2.34.1

[PATCH v5 6/9] usb: misc: qcom_eud: add role-based EUD control

[Elson Serrao]

EUD functions by presenting itself as a USB device to the host PC and is
therefore only applicable when the port operates in device role. Keeping
EUD enabled in other roles provides no benefit and unnecessarily keeps
the associated PHY resources enabled. Furthermore, enabling EUD in host
role can cause the USB controller to misbehave because the EUD hub
supports only a single upstream-facing port.

Address this by treating EUD as usable only in device role. The
role-switch callback enables or disables EUD as the port enters or
leaves device role. A sysfs enable request made outside device role is
recorded and honored when the port subsequently switches to device role.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 drivers/usb/misc/qcom_eud.c | 46 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index e83a4402e4b8..538e070cc140 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -15,6 +15,7 @@
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/string_choices.h>
 #include <linux/sysfs.h>
 #include <linux/usb/role.h>
 #include <linux/firmware/qcom/qcom_scm.h>
@@ -55,6 +56,8 @@ struct eud_chip {
 	struct device			*dev;
 	void __iomem			*base;
 	struct eud_path			*paths[EUD_MAX_PORTS];
+	/* serializes EUD control operations */
+	struct mutex			state_lock;
 	phys_addr_t			mode_mgr;
 	unsigned int			int_status;
 	int				irq;
@@ -156,17 +159,33 @@ static ssize_t enable_store(struct device *dev,
 		const char *buf, size_t count)
 {
 	struct eud_chip *chip = dev_get_drvdata(dev);
+	struct eud_path *path;
 	bool enable;
 	int ret;
 
 	if (kstrtobool(buf, &enable))
 		return -EINVAL;
 
+	guard(mutex)(&chip->state_lock);
+
 	/* Skip operation if already in desired state */
 	if (chip->enabled == enable)
 		return count;
 
 	if (enable) {
+		path = chip->paths[chip->port_idx];
+
+		/*
+		 * If not yet in device role, honor the userspace request and defer
+		 * EUD enablement until the port transitions to device role in the
+		 * set_role callback.
+		 */
+		if (path->curr_role != USB_ROLE_DEVICE) {
+			dev_info(chip->dev, "Deferring EUD enable until port enters device mode\n");
+			chip->enabled = enable;
+			return count;
+		}
+
 		ret = enable_eud(chip);
 		if (ret) {
 			dev_err(chip->dev, "failed to enable eud\n");
@@ -304,7 +323,30 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
 static int eud_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
 {
 	struct eud_path *path = usb_role_switch_get_drvdata(sw);
-	int ret;
+	struct eud_chip *chip = path->chip;
+	int ret = 0;
+
+	guard(mutex)(&chip->state_lock);
+
+	/*
+	 * EUD is usable only in device role. Power it down for every other
+	 * role to avoid keeping an unusable module 'ON'. chip->enabled
+	 * preserves user's sysfs configuration and is not modified across
+	 * role transitions.
+	 */
+	if (chip->enabled && path->num == chip->port_idx && role != path->curr_role) {
+		if (role == USB_ROLE_DEVICE)
+			ret = enable_eud(chip);
+		else if (path->curr_role == USB_ROLE_DEVICE)
+			ret = disable_eud(chip);
+
+		if (ret) {
+			dev_err(chip->dev, "failed to %s EUD for role %s: %d\n",
+				str_enable_disable(role == USB_ROLE_DEVICE),
+				usb_role_string(role), ret);
+			return ret;
+		}
+	}
 
 	/* Forward the role request to the USB controller */
 	ret = usb_role_switch_set_role(path->controller_sw, role);
@@ -431,6 +473,8 @@ static int eud_probe(struct platform_device *pdev)
 
 	chip->dev = &pdev->dev;
 
+	mutex_init(&chip->state_lock);
+
 	for_each_child_of_node_scoped(np, child) {
 		ret = eud_init_path(chip, child);
 		if (ret)
-- 
2.34.1

[PATCH v5 7/9] usb: misc: qcom_eud: fix virtual attach/detach event handling

[Elson Serrao]

EUD provides virtual USB attach/detach events to simulate cable
plug/unplug while maintaining the physical debug connection. However,
the current implementation incorrectly sets the USB role to HOST on
virtual detach, which doesn't represent the disconnected state.

Fix the virtual detach handling by setting the USB role to NONE
instead of HOST, correctly representing the disconnected state.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Peter Chen <peter.chen@kernel.org>
---
 drivers/usb/misc/qcom_eud.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index 538e070cc140..a02f3535956d 100644
--- a/drivers/usb/misc/qcom_eud.c
+++ b/drivers/usb/misc/qcom_eud.c
@@ -306,10 +306,26 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
 
 	path = chip->paths[chip->port_idx];
 
+	/*
+	 * EUD virtual attach/detach event handling for low power debugging:
+	 *
+	 * When EUD is enabled in debug mode, the device remains physically
+	 * connected to the PC throughout the debug session, keeping the USB
+	 * controller active. This prevents testing of low power scenarios that
+	 * require USB disconnection.
+	 *
+	 * EUD solves this by providing virtual USB attach/detach events while
+	 * maintaining the physical connection. These events are triggered from
+	 * the Host PC via the enumerated EUD control interface and delivered
+	 * to the EUD driver as interrupts.
+	 *
+	 * These notifications are forwarded to the USB controller through role
+	 * switch framework.
+	 */
 	if (chip->usb_attached)
 		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_DEVICE);
 	else
-		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_HOST);
+		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_NONE);
 	if (ret)
 		dev_err(chip->dev, "failed to set role switch\n");
 
-- 
2.34.1

[PATCH v5 8/9] arm64: dts: qcom: kodiak: Describe EUD UTMI path using child node

[Elson Serrao]

The existing EUD description uses a legacy single-path representation
that assumes uniform UTMI routing. This was sufficient for minimal
configurations where the USB port operated only in device mode and role
switching was not considered.

Update the description to explicitly model the topology using eud path
child node and add a role-switch declaration to reflect role-dependent
UTMI routing. Also on this SoC, the EUD hardware intercepts only the
primary UTMI path. So remove the USB endpoint mapping to the secondary
controller and associate it with the primary controller.

With the UTMI path now accurately described, enable the EUD by default.
The connector side of the path is left unspecified, allowing board-level
DTS files to describe the physical connector mapping.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 arch/arm64/boot/dts/qcom/kodiak.dtsi | 35 +++++++++++++++++-----------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/kodiak.dtsi b/arch/arm64/boot/dts/qcom/kodiak.dtsi
index fa540d8c2615..be9d02760a98 100644
--- a/arch/arm64/boot/dts/qcom/kodiak.dtsi
+++ b/arch/arm64/boot/dts/qcom/kodiak.dtsi
@@ -4404,12 +4404,6 @@ usb_2: usb@8c00000 {
 			phy-names = "usb2-phy";
 			maximum-speed = "high-speed";
 			usb-role-switch;
-
-			port {
-				usb2_role_switch: endpoint {
-					remote-endpoint = <&eud_ep>;
-				};
-			};
 		};
 
 		qspi: spi@88dc000 {
@@ -4736,16 +4730,28 @@ eud: eud@88e0000 {
 			      <0 0x88e2000 0 0x1000>;
 			interrupts-extended = <&pdc 11 IRQ_TYPE_LEVEL_HIGH>;
 
-			status = "disabled";
+			#address-cells = <1>;
+			#size-cells = <0>;
 
-			ports {
-				#address-cells = <1>;
-				#size-cells = <0>;
+			eud0: eud-path@0 {
+				reg = <0>;
+				usb-role-switch;
 
-				port@0 {
-					reg = <0>;
-					eud_ep: endpoint {
-						remote-endpoint = <&usb2_role_switch>;
+				ports {
+					#address-cells = <1>;
+					#size-cells = <0>;
+
+					port@0 {
+						reg = <0>;
+						eud_usb: endpoint {
+							remote-endpoint = <&usb_1_dwc3_hs>;
+						};
+					};
+
+					port@1 {
+						reg = <1>;
+						eud_con: endpoint {
+						};
 					};
 				};
 			};
@@ -4972,6 +4978,7 @@ port@0 {
 					reg = <0>;
 
 					usb_1_dwc3_hs: endpoint {
+						remote-endpoint = <&eud_usb>;
 					};
 				};
 
-- 
2.34.1

[PATCH v5 9/9] arm64: dts: qcom: Map USB connector to EUD on Kodiak boards

[Elson Serrao]

On Kodiak-based boards, the primary USB connector is connected through
the EUD on the High-Speed path. Update the board-level descriptions to
map the USB connector endpoint to EUD, reflecting the intended hardware
topology.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts     | 10 +++++-----
 arch/arm64/boot/dts/qcom/qcm6490-particle-tachyon.dts  | 10 +++++-----
 arch/arm64/boot/dts/qcom/qcm6490-shift-otter.dts       | 10 +++++-----
 arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts           | 10 +++++-----
 .../boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts |  4 ++--
 .../boot/dts/qcom/qcs6490-thundercomm-rubikpi3.dts     | 10 +++++-----
 arch/arm64/boot/dts/qcom/sm7325-motorola-dubai.dts     |  4 ++--
 arch/arm64/boot/dts/qcom/sm7325-nothing-spacewar.dts   | 10 +++++-----
 8 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
index 04cb9230d29f..c213e06a4428 100644
--- a/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
+++ b/arch/arm64/boot/dts/qcom/qcm6490-fairphone-fp5.dts
@@ -98,7 +98,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1478,10 +1478,6 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_hsphy {
 	vdda-pll-supply = <&vreg_l10c>;
 	vdda18-supply = <&vreg_l1c>;
@@ -1521,3 +1517,7 @@ &wifi {
 	qcom,calibration-variant = "Fairphone_5";
 	status = "okay";
 };
+
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
diff --git a/arch/arm64/boot/dts/qcom/qcm6490-particle-tachyon.dts b/arch/arm64/boot/dts/qcom/qcm6490-particle-tachyon.dts
index bf18c4852081..e9c0463daa53 100644
--- a/arch/arm64/boot/dts/qcom/qcm6490-particle-tachyon.dts
+++ b/arch/arm64/boot/dts/qcom/qcm6490-particle-tachyon.dts
@@ -74,7 +74,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -826,10 +826,6 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_hsphy {
 	vdda-pll-supply = <&vreg_l10c_0p88>;
 	vdda33-supply = <&vreg_l2b_3p072>;
@@ -862,3 +858,7 @@ &usb_2_hsphy {
 &usb_dp_qmpphy_out {
 	remote-endpoint = <&pmic_glink_ss_in>;
 };
+
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
diff --git a/arch/arm64/boot/dts/qcom/qcm6490-shift-otter.dts b/arch/arm64/boot/dts/qcom/qcm6490-shift-otter.dts
index 797f37596bf1..650c4fbc1606 100644
--- a/arch/arm64/boot/dts/qcom/qcm6490-shift-otter.dts
+++ b/arch/arm64/boot/dts/qcom/qcm6490-shift-otter.dts
@@ -84,7 +84,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -952,10 +952,6 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_hsphy {
 	vdda-pll-supply = <&vreg_l10c>;
 	vdda18-supply = <&vreg_l1c>;
@@ -986,6 +982,10 @@ &usb_dp_qmpphy_out {
 	remote-endpoint = <&pmic_glink_ss_in>;
 };
 
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
+
 &venus {
 	firmware-name = "qcom/qcm6490/SHIFT/otter/venus.mbn";
 
diff --git a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
index 37a3b51323ce..514d6d7fedb5 100644
--- a/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
+++ b/arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts
@@ -211,7 +211,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1402,14 +1402,14 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_dwc3_ss {
 	remote-endpoint = <&usb_dp_qmpphy_usb_ss_in>;
 };
 
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
+
 &usb_1_hsphy {
 	vdda-pll-supply = <&vreg_l10c_0p88>;
 	vdda33-supply = <&vreg_l2b_3p072>;
diff --git a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
index a5ad796cb65d..1d992dcc89ed 100644
--- a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
+++ b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-minipc-g1iot.dts
@@ -77,7 +77,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1046,7 +1046,7 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
+&eud_con {
 	remote-endpoint = <&pmic_glink_hs_in>;
 };
 
diff --git a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-rubikpi3.dts b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-rubikpi3.dts
index f47efca42d48..387c38aa87d2 100644
--- a/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-rubikpi3.dts
+++ b/arch/arm64/boot/dts/qcom/qcs6490-thundercomm-rubikpi3.dts
@@ -93,7 +93,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1090,10 +1090,6 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_hsphy {
 	vdda-pll-supply = <&vreg_l10c_0p88>;
 	vdda33-supply = <&vreg_l2b_3p072>;
@@ -1127,6 +1123,10 @@ &usb_dp_qmpphy_out {
 	remote-endpoint = <&pmic_glink_ss_in>;
 };
 
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
+
 &ufs_mem_hc {
 	reset-gpios = <&tlmm 175 GPIO_ACTIVE_LOW>;
 	vcc-supply = <&vreg_l7b_2p952>;
diff --git a/arch/arm64/boot/dts/qcom/sm7325-motorola-dubai.dts b/arch/arm64/boot/dts/qcom/sm7325-motorola-dubai.dts
index 3c836e196b19..99913ba41d55 100644
--- a/arch/arm64/boot/dts/qcom/sm7325-motorola-dubai.dts
+++ b/arch/arm64/boot/dts/qcom/sm7325-motorola-dubai.dts
@@ -98,7 +98,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1431,7 +1431,7 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
+&eud_con {
 	remote-endpoint = <&pmic_glink_hs_in>;
 };
 
diff --git a/arch/arm64/boot/dts/qcom/sm7325-nothing-spacewar.dts b/arch/arm64/boot/dts/qcom/sm7325-nothing-spacewar.dts
index cb59c122f6f6..a2e160f3f46e 100644
--- a/arch/arm64/boot/dts/qcom/sm7325-nothing-spacewar.dts
+++ b/arch/arm64/boot/dts/qcom/sm7325-nothing-spacewar.dts
@@ -99,7 +99,7 @@ port@0 {
 					reg = <0>;
 
 					pmic_glink_hs_in: endpoint {
-						remote-endpoint = <&usb_1_dwc3_hs>;
+						remote-endpoint = <&eud_con>;
 					};
 				};
 
@@ -1440,10 +1440,6 @@ &usb_1 {
 	status = "okay";
 };
 
-&usb_1_dwc3_hs {
-	remote-endpoint = <&pmic_glink_hs_in>;
-};
-
 &usb_1_hsphy {
 	vdda-pll-supply = <&vdd_a_usbhs_core>;
 	vdda18-supply = <&vdd_a_usbhs_1p8>;
@@ -1459,3 +1455,7 @@ &venus {
 &wifi {
 	status = "okay";
 };
+
+&eud_con {
+	remote-endpoint = <&pmic_glink_hs_in>;
+};
-- 
2.34.1

Re: [PATCH v5 4/9] usb: misc: qcom_eud: add per-path role switch support

[Peter Chen]

On 26-08-02 20:15:29, Elson Serrao wrote:
> The EUD hardware can support multiple High-Speed USB paths, each connected
> to different USB controllers. The current implementation uses a single
> chip-level role switch, which cannot properly handle multi-path
> configurations where each path needs independent role management. Since
> EUD is physically present between the USB connector and the controller,
> it should also relay the role change requests from the connector.
> 
> Restructure the driver to support per-path role switches and remove the
> chip-level role switch. Additionally, as EUD need not modify the USB
> role upon enabling, remove the unnecessary role switch call from
> enable_eud().
> 
> Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>

Reviewed-by: Peter Chen <peter.chen@kernel.org>

Peter
> ---
>  drivers/usb/misc/qcom_eud.c | 100 +++++++++++++++++++++++++++++-------
>  1 file changed, 81 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
> index 03d1c200658c..48a4441b0c9c 100644
> --- a/drivers/usb/misc/qcom_eud.c
> +++ b/drivers/usb/misc/qcom_eud.c
> @@ -44,12 +44,15 @@ static const char * const eud_port_names[] = {
>  struct eud_path {
>  	struct eud_chip		*chip;
>  	struct phy		*phy;
> +	struct usb_role_switch	*controller_sw;
> +	struct usb_role_switch	*eud_sw;
> +	enum usb_role		curr_role;
> +	char			name[16];
>  	u8			num;
>  };
>  
>  struct eud_chip {
>  	struct device			*dev;
> -	struct usb_role_switch		*role_sw;
>  	void __iomem			*base;
>  	struct eud_path			*paths[EUD_MAX_PORTS];
>  	phys_addr_t			mode_mgr;
> @@ -123,7 +126,7 @@ static int enable_eud(struct eud_chip *priv)
>  	writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
>  			priv->base + EUD_REG_INT1_EN_MASK);
>  
> -	return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
> +	return 0;
>  }
>  
>  static int disable_eud(struct eud_chip *priv)
> @@ -270,12 +273,15 @@ static irqreturn_t handle_eud_irq(int irq, void *data)
>  static irqreturn_t handle_eud_irq_thread(int irq, void *data)
>  {
>  	struct eud_chip *chip = data;
> +	struct eud_path *path;
>  	int ret;
>  
> +	path = chip->paths[chip->port_idx];
> +
>  	if (chip->usb_attached)
> -		ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
> +		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_DEVICE);
>  	else
> -		ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
> +		ret = usb_role_switch_set_role(path->controller_sw, USB_ROLE_HOST);
>  	if (ret)
>  		dev_err(chip->dev, "failed to set role switch\n");
>  
> @@ -286,17 +292,39 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
>  	return IRQ_HANDLED;
>  }
>  
> -static void eud_role_switch_release(void *data)
> +static int eud_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
>  {
> -	struct eud_chip *chip = data;
> +	struct eud_path *path = usb_role_switch_get_drvdata(sw);
> +	int ret;
> +
> +	/* Forward the role request to the USB controller */
> +	ret = usb_role_switch_set_role(path->controller_sw, role);
> +	if (ret) {
> +		dev_err(path->chip->dev, "failed to set role %s for port %u: %d\n",
> +			usb_role_string(role), path->num, ret);
> +		return ret;
> +	}
> +
> +	path->curr_role = role;
>  
> -	usb_role_switch_put(chip->role_sw);
> +	return 0;
> +}
> +
> +static void eud_path_role_switch_release(void *data)
> +{
> +	struct eud_path *path = data;
> +
> +	usb_role_switch_unregister(path->eud_sw);
> +	usb_role_switch_put(path->controller_sw);
>  }
>  
>  static int eud_init_path(struct eud_chip *chip, struct device_node *np)
>  {
> +	struct usb_role_switch_desc role_sw_desc = {NULL};
> +	struct usb_role_switch *sw;
>  	struct device_node *controller_node;
>  	struct eud_path *path;
> +	const char *dr_mode = "";
>  	u32 path_num;
>  	int ret;
>  
> @@ -327,14 +355,57 @@ static int eud_init_path(struct eud_chip *chip, struct device_node *np)
>  				     "failed to get controller node for path %u\n", path_num);
>  
>  	path->phy = devm_of_phy_get_by_index(chip->dev, controller_node, 0);
> -	of_node_put(controller_node);
> -
> -	if (IS_ERR(path->phy))
> +	if (IS_ERR(path->phy)) {
> +		of_node_put(controller_node);
>  		return dev_err_probe(chip->dev, PTR_ERR(path->phy),
>  				     "failed to get PHY for path %d\n", path_num);
> +	}
>  
>  	chip->paths[path_num] = path;
>  
> +	of_property_read_string(controller_node, "dr_mode", &dr_mode);
> +
> +	if (!strcmp(dr_mode, "host"))
> +		path->curr_role = USB_ROLE_HOST;
> +	else if (!strcmp(dr_mode, "peripheral"))
> +		path->curr_role = USB_ROLE_DEVICE;
> +	else
> +		path->curr_role = USB_ROLE_NONE;
> +
> +	/* No role switch needed for fixed role controllers */
> +	if (path->curr_role != USB_ROLE_NONE) {
> +		of_node_put(controller_node);
> +		return 0;
> +	}
> +
> +	sw = usb_role_switch_find_by_fwnode(of_fwnode_handle(controller_node));
> +	if (!sw) {
> +		of_node_put(controller_node);
> +		return dev_err_probe(chip->dev, -EPROBE_DEFER,
> +				     "Failed to get controller role switch for path %d\n",
> +				     path_num);
> +	}
> +	path->controller_sw = sw;
> +
> +	of_node_put(controller_node);
> +
> +	role_sw_desc.fwnode = of_fwnode_handle(np);
> +	role_sw_desc.set = eud_role_switch_set;
> +	role_sw_desc.driver_data = path;
> +	snprintf(path->name, sizeof(path->name), "eud-path%u", path_num);
> +	role_sw_desc.name = path->name;
> +
> +	path->eud_sw = usb_role_switch_register(chip->dev, &role_sw_desc);
> +	if (IS_ERR(path->eud_sw)) {
> +		usb_role_switch_put(path->controller_sw);
> +		return dev_err_probe(chip->dev, PTR_ERR(path->eud_sw),
> +				     "Failed to register EUD role switch for path %d\n", path_num);
> +	}
> +
> +	ret = devm_add_action_or_reset(chip->dev, eud_path_role_switch_release, path);
> +	if (ret)
> +		return ret;
> +
>  	return 0;
>  }
>  
> @@ -361,15 +432,6 @@ static int eud_probe(struct platform_device *pdev)
>  	if (!chip->paths[0])
>  		return dev_err_probe(chip->dev, -ENODEV, "primary path not found\n");
>  
> -	chip->role_sw = usb_role_switch_get(&pdev->dev);
> -	if (IS_ERR(chip->role_sw))
> -		return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
> -					"failed to get role switch\n");
> -
> -	ret = devm_add_action_or_reset(chip->dev, eud_role_switch_release, chip);
> -	if (ret)
> -		return ret;
> -
>  	chip->base = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(chip->base))
>  		return PTR_ERR(chip->base);
> -- 
> 2.34.1
> 

-- 

Thanks,
Peter Chen

Re: [PATCH v5 6/9] usb: misc: qcom_eud: add role-based EUD control

[Peter Chen]

On 26-08-02 20:15:31, Elson Serrao wrote:
> EUD functions by presenting itself as a USB device to the host PC and is
> therefore only applicable when the port operates in device role. Keeping
> EUD enabled in other roles provides no benefit and unnecessarily keeps
> the associated PHY resources enabled. Furthermore, enabling EUD in host
> role can cause the USB controller to misbehave because the EUD hub
> supports only a single upstream-facing port.
> 
> Address this by treating EUD as usable only in device role. The
> role-switch callback enables or disables EUD as the port enters or
> leaves device role. A sysfs enable request made outside device role is
> recorded and honored when the port subsequently switches to device role.
> 
> Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>

Reviewed-by: Peter Chen <peter.chen@kernel.org>

Peter
> ---
>  drivers/usb/misc/qcom_eud.c | 46 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
> index e83a4402e4b8..538e070cc140 100644
> --- a/drivers/usb/misc/qcom_eud.c
> +++ b/drivers/usb/misc/qcom_eud.c
> @@ -15,6 +15,7 @@
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
> +#include <linux/string_choices.h>
>  #include <linux/sysfs.h>
>  #include <linux/usb/role.h>
>  #include <linux/firmware/qcom/qcom_scm.h>
> @@ -55,6 +56,8 @@ struct eud_chip {
>  	struct device			*dev;
>  	void __iomem			*base;
>  	struct eud_path			*paths[EUD_MAX_PORTS];
> +	/* serializes EUD control operations */
> +	struct mutex			state_lock;
>  	phys_addr_t			mode_mgr;
>  	unsigned int			int_status;
>  	int				irq;
> @@ -156,17 +159,33 @@ static ssize_t enable_store(struct device *dev,
>  		const char *buf, size_t count)
>  {
>  	struct eud_chip *chip = dev_get_drvdata(dev);
> +	struct eud_path *path;
>  	bool enable;
>  	int ret;
>  
>  	if (kstrtobool(buf, &enable))
>  		return -EINVAL;
>  
> +	guard(mutex)(&chip->state_lock);
> +
>  	/* Skip operation if already in desired state */
>  	if (chip->enabled == enable)
>  		return count;
>  
>  	if (enable) {
> +		path = chip->paths[chip->port_idx];
> +
> +		/*
> +		 * If not yet in device role, honor the userspace request and defer
> +		 * EUD enablement until the port transitions to device role in the
> +		 * set_role callback.
> +		 */
> +		if (path->curr_role != USB_ROLE_DEVICE) {
> +			dev_info(chip->dev, "Deferring EUD enable until port enters device mode\n");
> +			chip->enabled = enable;
> +			return count;
> +		}
> +
>  		ret = enable_eud(chip);
>  		if (ret) {
>  			dev_err(chip->dev, "failed to enable eud\n");
> @@ -304,7 +323,30 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
>  static int eud_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
>  {
>  	struct eud_path *path = usb_role_switch_get_drvdata(sw);
> -	int ret;
> +	struct eud_chip *chip = path->chip;
> +	int ret = 0;
> +
> +	guard(mutex)(&chip->state_lock);
> +
> +	/*
> +	 * EUD is usable only in device role. Power it down for every other
> +	 * role to avoid keeping an unusable module 'ON'. chip->enabled
> +	 * preserves user's sysfs configuration and is not modified across
> +	 * role transitions.
> +	 */
> +	if (chip->enabled && path->num == chip->port_idx && role != path->curr_role) {
> +		if (role == USB_ROLE_DEVICE)
> +			ret = enable_eud(chip);
> +		else if (path->curr_role == USB_ROLE_DEVICE)
> +			ret = disable_eud(chip);
> +
> +		if (ret) {
> +			dev_err(chip->dev, "failed to %s EUD for role %s: %d\n",
> +				str_enable_disable(role == USB_ROLE_DEVICE),
> +				usb_role_string(role), ret);
> +			return ret;
> +		}
> +	}
>  
>  	/* Forward the role request to the USB controller */
>  	ret = usb_role_switch_set_role(path->controller_sw, role);
> @@ -431,6 +473,8 @@ static int eud_probe(struct platform_device *pdev)
>  
>  	chip->dev = &pdev->dev;
>  
> +	mutex_init(&chip->state_lock);
> +
>  	for_each_child_of_node_scoped(np, child) {
>  		ret = eud_init_path(chip, child);
>  		if (ret)
> -- 
> 2.34.1
> 

-- 

Thanks,
Peter Chen

Re: [PATCH v5 8/9] arm64: dts: qcom: kodiak: Describe EUD UTMI path using child node

[Krzysztof Kozlowski]

On Sun, Aug 02, 2026 at 08:15:33PM -0700, Elson Serrao wrote:
> -			ports {
> -				#address-cells = <1>;
> -				#size-cells = <0>;
> +			eud0: eud-path@0 {
> +				reg = <0>;
> +				usb-role-switch;
>  
> -				port@0 {
> -					reg = <0>;
> -					eud_ep: endpoint {
> -						remote-endpoint = <&usb2_role_switch>;
> +				ports {
> +					#address-cells = <1>;
> +					#size-cells = <0>;
> +
> +					port@0 {
> +						reg = <0>;
> +						eud_usb: endpoint {
> +							remote-endpoint = <&usb_1_dwc3_hs>;

Your patches introduce new warnings:
'/soc@0/usb@a600000/ports/port@0/endpoint' is not bidirectional

> +						};
> +					};
> +
> +					port@1 {
> +						reg = <1>;
> +						eud_con: endpoint {
> +						};
>  					};
>  				};
>  			};
> @@ -4972,6 +4978,7 @@ port@0 {

Best regards,
Krzysztof

Re: [PATCH v5 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing

[Krzysztof Kozlowski]

On Sun, Aug 02, 2026 at 08:15:26PM -0700, Elson Serrao wrote:
> The Qualcomm Embedded USB Debugger (EUD) can intercept one or two
> High-Speed UTMI paths depending on the SoC. For example, SC7280 supports
> EUD on the primary UTMI path only, while SM8350 supports EUD on both
> primary and secondary UTMI paths.
> 
> Each UTMI path connects an independent USB controller/connector pair and
> forms its own role-switch domain. EUD routes traffic based on USB role.
> In device role the debug hub is inserted, while in host role it is
> bypassed.
> 
> The existing binding models EUD using a flattened ports representation.
> While sufficient for fixed device-role configurations, it cannot naturally
> associate a controller, connector, and role switch with a specific
> EUD-routable path. This is problematic for role-switch capable ports and
> becomes more pronounced on SoCs with multiple paths. In such cases, each
> path forms an independent role-switch domain and requires per-path role
> awareness.
> 
> Model each UTMI path as a separate child node with its own OF graph. Add
> an SM8350 compatible for dual-path EUD topologies while retaining the
> legacy ports representation for backward compatibility.
> 
> Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
> ---
>  .../bindings/soc/qcom/qcom,eud.yaml           | 128 +++++++++++++++++-
>  1 file changed, 127 insertions(+), 1 deletion(-)

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof

Re: [PATCH v5 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing

[Rob Herring]

On Fri, Aug 07, 2026 at 09:20:26AM +0200, Krzysztof Kozlowski wrote:
> On Sun, Aug 02, 2026 at 08:15:26PM -0700, Elson Serrao wrote:
> > The Qualcomm Embedded USB Debugger (EUD) can intercept one or two
> > High-Speed UTMI paths depending on the SoC. For example, SC7280 supports
> > EUD on the primary UTMI path only, while SM8350 supports EUD on both
> > primary and secondary UTMI paths.
> > 
> > Each UTMI path connects an independent USB controller/connector pair and
> > forms its own role-switch domain. EUD routes traffic based on USB role.
> > In device role the debug hub is inserted, while in host role it is
> > bypassed.
> > 
> > The existing binding models EUD using a flattened ports representation.
> > While sufficient for fixed device-role configurations, it cannot naturally
> > associate a controller, connector, and role switch with a specific
> > EUD-routable path. This is problematic for role-switch capable ports and
> > becomes more pronounced on SoCs with multiple paths. In such cases, each
> > path forms an independent role-switch domain and requires per-path role
> > awareness.
> > 
> > Model each UTMI path as a separate child node with its own OF graph. Add
> > an SM8350 compatible for dual-path EUD topologies while retaining the
> > legacy ports representation for backward compatibility.
> > 
> > Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
> > ---
> >  .../bindings/soc/qcom/qcom,eud.yaml           | 128 +++++++++++++++++-
> >  1 file changed, 127 insertions(+), 1 deletion(-)
> 
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

sashiko correctly points out the oneOf logic is flawed.