usb: mtu3: re-enable controller to accept LPM request after LPM resume

After the controller receives a LPM request, it will reject the LPM
request, and need software to re-enable it after LPM resume if the
controller doesn't remote wakeup from L1 automatically
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mtu3/mtu3_core.c

@@ -176,7 +176,7 @@ static void mtu3_intr_enable(struct mtu3 *mtu)
 	mtu3_writel(mbase, U3D_LV1IESR, value);
 
 	/* Enable U2 common USB interrupts */
-	value = SUSPEND_INTR | RESUME_INTR | RESET_INTR;
+	value = SUSPEND_INTR | RESUME_INTR | RESET_INTR | LPM_RESUME_INTR;
 	mtu3_writel(mbase, U3D_COMMON_USB_INTR_ENABLE, value);
 
 	if (mtu->is_u3_ip) {
@@ -692,6 +692,12 @@ static irqreturn_t mtu3_u2_common_isr(struct mtu3 *mtu)
 	if (u2comm & RESET_INTR)
 		mtu3_gadget_reset(mtu);
 
+	if (u2comm & LPM_RESUME_INTR) {
+		if (!(mtu3_readl(mbase, U3D_POWER_MANAGEMENT) & LPM_HRWE))
+			mtu3_setbits(mbase, U3D_USB20_MISC_CONTROL,
+				     LPM_U3_ACK_EN);
+	}
+
 	return IRQ_HANDLED;
 }