phy: stm32: manage optional vbus regulator on phy_power_on/off

This patch adds support for optional vbus regulator.
It is managed on phy_power_on/off calls and may be needed for host mode.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20210517120821.26466-3-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/st/phy-stm32-usbphyc.c

@@ -57,6 +57,7 @@ struct pll_params {
 struct stm32_usbphyc_phy {
 	struct phy *phy;
 	struct stm32_usbphyc *usbphyc;
+	struct regulator *vbus;
 	u32 index;
 	bool active;
 };
@@ -291,9 +292,31 @@ static int stm32_usbphyc_phy_exit(struct phy *phy)
 	return stm32_usbphyc_pll_disable(usbphyc);
 }
 
+static int stm32_usbphyc_phy_power_on(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+
+	if (usbphyc_phy->vbus)
+		return regulator_enable(usbphyc_phy->vbus);
+
+	return 0;
+}
+
+static int stm32_usbphyc_phy_power_off(struct phy *phy)
+{
+	struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+
+	if (usbphyc_phy->vbus)
+		return regulator_disable(usbphyc_phy->vbus);
+
+	return 0;
+}
+
 static const struct phy_ops stm32_usbphyc_phy_ops = {
 	.init = stm32_usbphyc_phy_init,
 	.exit = stm32_usbphyc_phy_exit,
+	.power_on = stm32_usbphyc_phy_power_on,
+	.power_off = stm32_usbphyc_phy_power_off,
 	.owner = THIS_MODULE,
 };
 
@@ -519,6 +542,14 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
 		usbphyc->phys[port]->index = index;
 		usbphyc->phys[port]->active = false;
 
+		usbphyc->phys[port]->vbus = devm_regulator_get_optional(&phy->dev, "vbus");
+		if (IS_ERR(usbphyc->phys[port]->vbus)) {
+			ret = PTR_ERR(usbphyc->phys[port]->vbus);
+			if (ret == -EPROBE_DEFER)
+				goto put_child;
+			usbphyc->phys[port]->vbus = NULL;
+		}
+
 		port++;
 	}