The RZ/V2H USB2 PHY requires control of the VBUS selection line
(VBENCTL) through a mux controller described in the device tree as
"mux-controller". This change adds support for registering the
rzv2h-usb-vbenctl auxiliary driver during probe.

This enables proper management of USB2.0 VBUS source selection on
platforms using the RZ/V2H SoC.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
---
v4->v5:
 - Update mux_name to "vbenctl" to match the driver name.
 - Updated commit message.

v3->v4:
 - No changes.

v2->v3:
 - Use __devm_auxiliary_device_create() to create the auxiliary device.

v1->v2:
 - New patch

 drivers/reset/Kconfig               |  1 +
 drivers/reset/reset-rzv2h-usb2phy.c | 44 +++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 6e5d6deffa7d..d86a4a0766b2 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -257,6 +257,7 @@ config RESET_RZG2L_USBPHY_CTRL
 config RESET_RZV2H_USB2PHY
 	tristate "Renesas RZ/V2H(P) (and similar SoCs) USB2PHY Reset driver"
 	depends on ARCH_RENESAS || COMPILE_TEST
+	select AUXILIARY_BUS
 	help
 	  Support for USB2PHY Port reset Control found on the RZ/V2H(P) SoC
 	  (and similar SoCs).
diff --git a/drivers/reset/reset-rzv2h-usb2phy.c b/drivers/reset/reset-rzv2h-usb2phy.c
index 5bdd39274612..15447a4f091f 100644
--- a/drivers/reset/reset-rzv2h-usb2phy.c
+++ b/drivers/reset/reset-rzv2h-usb2phy.c
@@ -5,8 +5,10 @@
  * Copyright (C) 2025 Renesas Electronics Corporation
  */
 
+#include <linux/auxiliary_bus.h>
 #include <linux/cleanup.h>
 #include <linux/delay.h>
+#include <linux/idr.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -14,6 +16,9 @@
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
 #include <linux/reset-controller.h>
+#include <linux/reset/reset_rzv2h_usb2phy.h>
+
+static DEFINE_IDA(auxiliary_ids);
 
 struct rzv2h_usb2phy_regval {
 	u16 reg;
@@ -104,6 +109,41 @@ static int rzv2h_usb2phy_reset_of_xlate(struct reset_controller_dev *rcdev,
 	return 0;
 }
 
+static void rzv2h_usb2phy_reset_ida_free(void *data)
+{
+	struct auxiliary_device *adev = data;
+
+	ida_free(&auxiliary_ids, adev->id);
+}
+
+static int rzv2h_usb2phy_reset_mux_register(struct device *dev,
+					    void __iomem *base,
+					    const char *mux_name)
+{
+	struct reset_rzv2h_usb2phy_adev *rdev;
+	struct auxiliary_device *adev;
+	int id;
+
+	rdev = devm_kzalloc(dev, sizeof(*rdev), GFP_KERNEL);
+	if (!rdev)
+		return -ENOMEM;
+
+	rdev->base = base;
+
+	id = ida_alloc(&auxiliary_ids, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	adev = __devm_auxiliary_device_create(dev, dev->driver->name,
+					      mux_name, rdev, id);
+	if (!adev) {
+		ida_free(&auxiliary_ids, id);
+		return -ENOMEM;
+	}
+
+	return devm_add_action_or_reset(dev, rzv2h_usb2phy_reset_ida_free, adev);
+}
+
 static void rzv2h_usb2phy_reset_pm_runtime_put(void *data)
 {
 	pm_runtime_put(data);
@@ -162,6 +202,10 @@ static int rzv2h_usb2phy_reset_probe(struct platform_device *pdev)
 	if (error)
 		return dev_err_probe(dev, error, "could not register reset controller\n");
 
+	error = rzv2h_usb2phy_reset_mux_register(dev, priv->base, "vbenctl");
+	if (error)
+		return dev_err_probe(dev, error, "could not register aux mux\n");
+
 	return 0;
 }
 
-- 
2.43.0