usb: phy: mxs: refine mxs_phy_disconnect_line

For non-otg mode, we keep the usage of disconnect line between phy analog
and digital unchanging; for otg mode, at peripheral role, we keep the usage
unchanging too, at host role, the digital part needs to know dp/dm change
to respond device's data pulse when it is at low power mode.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Li Jun <b47624@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Author: Li Jun

drivers/usb/phy/phy-mxs-usb.c

@@ -40,6 +40,7 @@
 
 #define BM_USBPHY_CTRL_SFTRST			BIT(31)
 #define BM_USBPHY_CTRL_CLKGATE			BIT(30)
+#define BM_USBPHY_CTRL_OTG_ID_VALUE		BIT(27)
 #define BM_USBPHY_CTRL_ENAUTOSET_USBCLKS	BIT(26)
 #define BM_USBPHY_CTRL_ENAUTOCLR_USBCLKGATE	BIT(25)
 #define BM_USBPHY_CTRL_ENVBUSCHG_WKUP		BIT(23)
@@ -255,6 +256,18 @@ static void __mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool disconnect)
 		usleep_range(500, 1000);
 }
 
+static bool mxs_phy_is_otg_host(struct mxs_phy *mxs_phy)
+{
+	void __iomem *base = mxs_phy->phy.io_priv;
+	u32 phyctrl = readl(base + HW_USBPHY_CTRL);
+
+	if (IS_ENABLED(CONFIG_USB_OTG) &&
+			!(phyctrl & BM_USBPHY_CTRL_OTG_ID_VALUE))
+		return true;
+
+	return false;
+}
+
 static void mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool on)
 {
 	bool vbus_is_on = false;
@@ -269,7 +282,7 @@ static void mxs_phy_disconnect_line(struct mxs_phy *mxs_phy, bool on)
 
 	vbus_is_on = mxs_phy_get_vbus_status(mxs_phy);
 
-	if (on && !vbus_is_on)
+	if (on && !vbus_is_on && !mxs_phy_is_otg_host(mxs_phy))
 		__mxs_phy_disconnect_line(mxs_phy, true);
 	else
 		__mxs_phy_disconnect_line(mxs_phy, false);