usb: ehci-generic: Add vbus-supply regulator support

Add vbus-supply regulator support.
On some board vbus is not controlled by the phy but by
an external regulator.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

drivers/usb/host/ehci-generic.c

@@ -11,6 +11,7 @@
 #include <asm/io.h>
 #include <dm.h>
 #include "ehci.h"
+#include <power/regulator.h>
 
 /*
  * Even though here we don't explicitly use "struct ehci_ctrl"
@@ -22,10 +23,56 @@ struct generic_ehci {
 	struct clk *clocks;
 	struct reset_ctl *resets;
 	struct phy phy;
+#ifdef CONFIG_DM_REGULATOR
+	struct udevice *vbus_supply;
+#endif
 	int clock_count;
 	int reset_count;
 };
 
+#ifdef CONFIG_DM_REGULATOR
+static int ehci_enable_vbus_supply(struct udevice *dev)
+{
+	struct generic_ehci *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = device_get_supply_regulator(dev, "vbus-supply",
+					  &priv->vbus_supply);
+	if (ret && ret != -ENOENT)
+		return ret;
+
+	if (priv->vbus_supply) {
+		ret = regulator_set_enable(priv->vbus_supply, true);
+		if (ret) {
+			dev_err(dev, "Error enabling VBUS supply\n");
+			return ret;
+		}
+	} else {
+		dev_dbg(dev, "No vbus supply\n");
+	}
+
+	return 0;
+}
+
+static int ehci_disable_vbus_supply(struct generic_ehci *priv)
+{
+	if (priv->vbus_supply)
+		return regulator_set_enable(priv->vbus_supply, false);
+	else
+		return 0;
+}
+#else
+static int ehci_enable_vbus_supply(struct udevice *dev)
+{
+	return 0;
+}
+
+static int ehci_disable_vbus_supply(struct generic_ehci *priv)
+{
+	return 0;
+}
+#endif
+
 static int ehci_usb_probe(struct udevice *dev)
 {
 	struct generic_ehci *priv = dev_get_priv(dev);
@@ -95,10 +142,14 @@ static int ehci_usb_probe(struct udevice *dev)
 		}
 	}
 
-	err = ehci_setup_phy(dev, &priv->phy, 0);
+	err = ehci_enable_vbus_supply(dev);
 	if (err)
 		goto reset_err;
 
+	err = ehci_setup_phy(dev, &priv->phy, 0);
+	if (err)
+		goto regulator_err;
+
 	hccr = map_physmem(dev_read_addr(dev), 0x100, MAP_NOCACHE);
 	hcor = (struct ehci_hcor *)((uintptr_t)hccr +
 				    HC_LENGTH(ehci_readl(&hccr->cr_capbase)));
@@ -114,6 +165,11 @@ phy_err:
 	if (ret)
 		dev_err(dev, "failed to shutdown usb phy\n");
 
+regulator_err:
+	ret = ehci_disable_vbus_supply(priv);
+	if (ret)
+		dev_err(dev, "failed to disable VBUS supply\n");
+
 reset_err:
 	ret = reset_release_all(priv->resets, priv->reset_count);
 	if (ret)
@@ -139,6 +195,10 @@ static int ehci_usb_remove(struct udevice *dev)
 	if (ret)
 		return ret;
 
+	ret = ehci_disable_vbus_supply(priv);
+	if (ret)
+		return ret;
+
 	ret =  reset_release_all(priv->resets, priv->reset_count);
 	if (ret)
 		return ret;