diff --git a/Documentation/devicetree/bindings/phy/apple,t6050-dp-phy.yaml b/Documentation/devicetree/bindings/phy/apple,t6050-dp-phy.yaml
index 52cb96f4a965b..fdc2e60461700 100644
--- a/Documentation/devicetree/bindings/phy/apple,t6050-dp-phy.yaml
+++ b/Documentation/devicetree/bindings/phy/apple,t6050-dp-phy.yaml
@@ -37,6 +37,7 @@ properties:
     const: 1
 
   apple,port-index:
+    $ref: /schemas/types.yaml#/definitions/uint32
     enum: [1, 2]
     description: Native Type-C port; the debug/proxy port is excluded
 
@@ -74,14 +75,20 @@ properties:
     description: Offset, mask and value tuples for the PIPE handler
 
   power-domains:
+    description:
+      A combo PHY may name the USB controller's domain fourth ("usb"). Its
+      USB2 PHY and digital banks are in that domain, and the PHY then holds it
+      while it runs, also on a port with no USB controller bound.
     minItems: 3
-    maxItems: 3
+    maxItems: 4
 
   power-domain-names:
+    minItems: 3
     items:
       - const: usb-aon
       - const: common
       - const: wrapper
+      - const: usb
 
   apple,tunable-axi2af:
     $ref: /schemas/types.yaml#/definitions/uint32-array
@@ -184,6 +191,10 @@ allOf:
       properties:
         '#phy-cells':
           const: 0
+        power-domains:
+          maxItems: 3
+        power-domain-names:
+          maxItems: 3
       if:
         required:
           - mode-switch
diff --git a/drivers/phy/apple/atc-t6050-combo.h b/drivers/phy/apple/atc-t6050-combo.h
index 1066748dc1afe..3c3454ceb64de 100644
--- a/drivers/phy/apple/atc-t6050-combo.h
+++ b/drivers/phy/apple/atc-t6050-combo.h
@@ -94,6 +94,8 @@ static int combo_stop(struct t6050_dp *dp)
 		if (!ret)
 			dp->usb2_active = false;
 	}
+	if (!ret && dp->ndomains > 3)
+		ret = atc_domain_set(&dp->domain[3], false);
 	if (!ret)
 		ret = atc_domain_set(&dp->domain[1], false);
 	if (!ret)
@@ -118,6 +120,12 @@ static int combo_start(struct t6050_dp *dp, enum combo_mode mode)
 	ret = atc_domain_set(&dp->domain[0], true);
 	if (!ret)
 		ret = atc_domain_set(&dp->domain[1], true);
+	/*
+	 * The USB2 PHY and digital banks are unclocked without the USB domain,
+	 * which a USB controller holds only while one is bound to this port.
+	 */
+	if (!ret && dp->ndomains > 3)
+		ret = atc_domain_set(&dp->domain[3], true);
 	if (!ret)
 		ret = APPLE_T6050_USB_RUN(&dp->usb_platform, apple_t6050_usb2_host);
 	if (!ret)
diff --git a/drivers/phy/apple/atc-t6050-dp.c b/drivers/phy/apple/atc-t6050-dp.c
index cafee096a6250..4479153919488 100644
--- a/drivers/phy/apple/atc-t6050-dp.c
+++ b/drivers/phy/apple/atc-t6050-dp.c
@@ -83,7 +83,9 @@ struct t6050_dp {
 	void __iomem *banks[45];
 	struct resource resources[45];
 	struct apple_tunable *tunables[ARRAY_SIZE(tunable_names)];
-	struct atc_domain domain[3]; /* USB AON, common, wrapper: native order. */
+	/* USB AON, common, wrapper: native order; a combo may add USB. */
+	struct atc_domain domain[4];
+	unsigned int ndomains;
 	u32 training[4][16];
 	u32 voltage[4], pre[4];
 	int rate;
@@ -605,14 +607,14 @@ static int t6050_typec_register(struct t6050_dp *dp)
 
 static int t6050_dp_probe(struct platform_device *pdev)
 {
-	static const char * const domains[] = {"usb-aon", "common", "wrapper"};
+	static const char * const domains[] = {"usb-aon", "common", "wrapper", "usb"};
 	struct device *dev = &pdev->dev;
 	struct t6050_dp *dp;
 	struct phy_provider *provider;
 	struct phy *phy;
 	struct resource *core;
 	void __iomem *base;
-	int ret;
+	int ndomains, ret;
 
 	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
 	if (!dp)
@@ -741,10 +743,16 @@ static int t6050_dp_probe(struct platform_device *pdev)
 		if (ret)
 			return ret;
 	}
-	/* Three named domains prevent automatic wrapper enable at probe time. */
-	if (of_count_phandle_with_args(dev->of_node, "power-domains", "#power-domain-cells") != 3)
+	/*
+	 * Named domains prevent automatic wrapper enable at probe time. A combo
+	 * PHY may also name the USB controller's domain, which its USB2 banks
+	 * are in (combo_start()).
+	 */
+	ndomains = of_count_phandle_with_args(dev->of_node, "power-domains", "#power-domain-cells");
+	if (ndomains != 3 && !(dp->combo && ndomains == 4))
 		return -EINVAL;
-	for (unsigned int i = 0; i < ARRAY_SIZE(domains); i++) {
+	dp->ndomains = ndomains;
+	for (unsigned int i = 0; i < dp->ndomains; i++) {
 		dp->domain[i].dev = dev_pm_domain_attach_by_name(dev, domains[i]);
 		if (IS_ERR_OR_NULL(dp->domain[i].dev))
 			return dev_err_probe(dev, dp->domain[i].dev ? PTR_ERR(dp->domain[i].dev) : -ENODEV,