phy: fsl-imx8mq-usb: add support for VBUS power control

This adds support to the PHY driver to power up/down the VBUS
voltage rail at the appropriate times.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/freescale/phy-fsl-imx8mq-usb.c

@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 
 #define PHY_CTRL0			0x0
 #define PHY_CTRL0_REF_SSP_EN		BIT(2)
@@ -24,6 +25,7 @@ struct imx8mq_usb_phy {
 	struct phy *phy;
 	struct clk *clk;
 	void __iomem *base;
+	struct regulator *vbus;
 };
 
 static int imx8mq_usb_phy_init(struct phy *phy)
@@ -55,6 +57,11 @@ static int imx8mq_usb_phy_init(struct phy *phy)
 static int imx8mq_phy_power_on(struct phy *phy)
 {
 	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = regulator_enable(imx_phy->vbus);
+	if (ret)
+		return ret;
 
 	return clk_prepare_enable(imx_phy->clk);
 }
@@ -64,6 +71,7 @@ static int imx8mq_phy_power_off(struct phy *phy)
 	struct imx8mq_usb_phy *imx_phy = phy_get_drvdata(phy);
 
 	clk_disable_unprepare(imx_phy->clk);
+	regulator_disable(imx_phy->vbus);
 
 	return 0;
 }
@@ -101,6 +109,10 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 	if (IS_ERR(imx_phy->phy))
 		return PTR_ERR(imx_phy->phy);
 
+	imx_phy->vbus = devm_regulator_get(dev, "vbus");
+	if (IS_ERR(imx_phy->vbus))
+		return PTR_ERR(imx_phy->vbus);
+
 	phy_set_drvdata(imx_phy->phy, imx_phy);
 
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);