usb: phy: omap_usb_phy: implement usb_phy_power() for AM437x

Newer AM437x silicon requires us to explicitly power up
the USB2 PHY. By implementing usb_phy_power() we can
achieve that.

Signed-off-by: Felipe Balbi <balbi@ti.com>

arch/arm/include/asm/arch-am33xx/hardware_am43xx.h

@@ -43,6 +43,11 @@
 #define VTP0_CTRL_ADDR			0x44E10E0C
 #define VTP1_CTRL_ADDR			0x48140E10
 
+/* USB CTRL Base Address */
+#define USB1_CTRL			0x44e10628
+#define USB1_CTRL_CM_PWRDN		BIT(0)
+#define USB1_CTRL_OTG_PWRDN		BIT(1)
+
 /* DDR Base address */
 #define DDR_PHY_CMD_ADDR		0x44E12000
 #define DDR_PHY_DATA_ADDR		0x44E120C8

drivers/usb/phy/omap_usb_phy.c

@@ -222,7 +222,22 @@ static void am437x_enable_usb2_phy2(struct omap_xhci *omap)
 
 void usb_phy_power(int on)
 {
-	return;
+	u32 val;
+
+	/* USB1_CTRL */
+	val = readl(USB1_CTRL);
+	if (on) {
+		/*
+		 * these bits are re-used on AM437x to power up/down the USB
+		 * CM and OTG PHYs, if we don't toggle them, USB will not be
+		 * functional on newer silicon revisions
+		 */
+		val &= ~(USB1_CTRL_CM_PWRDN | USB1_CTRL_OTG_PWRDN);
+	} else {
+		val |= USB1_CTRL_CM_PWRDN | USB1_CTRL_OTG_PWRDN;
+	}
+
+	writel(val, USB1_CTRL);
 }
 #endif /* CONFIG_AM437X_USB2PHY2_HOST */