[PATCH v4 4/9] usb: misc: qcom_eud: add per-path role switch support

Elson Serrao
2026-05-01T17:06:43Z

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 | 89 +++++++++++++++++++++++++++++--------
1 file changed, 70 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
index a624c44d5d59..7fbb74bf1599 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)
@@ -274,12 +277,15 @@ 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");

@@ -290,15 +296,36 @@ 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;
+ }

- usb_role_switch_put(chip->role_sw);
+ path->curr_role = role;
+
+ 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;
+ struct usb_role_switch *sw;
struct device_node *controller_node;
struct eud_path *path;
u32 path_num;
@@ -331,11 +358,44 @@ 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);
+ }
+
+ path->curr_role = USB_ROLE_NONE;
+
+ /* Fetch controller role switch if it is role switch capable */
+ if (of_property_read_bool(controller_node, "usb-role-switch")) {
+ 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;

chip->paths[path_num] = path;

@@ -365,15 +425,6 @@ 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