usb: dwc3: add request p1p2p3 quirk

This patch adds request P1/P2/P3 quirk for U2/U2/U3, and some special
platforms can configure that if it is needed.

[ balbi@ti.com : added DeviceTree binding documentation ]

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 7c54da1..600d3bc 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -377,6 +377,9 @@
 	if (dwc->u2ss_inp3_quirk)
 		reg |= DWC3_GUSB3PIPECTL_U2SSINP3OK;
 
+	if (dwc->req_p1p2p3_quirk)
+		reg |= DWC3_GUSB3PIPECTL_REQP1P2P3;
+
 	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
 
 	mdelay(100);
@@ -756,6 +759,8 @@
 				"snps,u2exit_lfps_quirk");
 		dwc->u2ss_inp3_quirk = of_property_read_bool(node,
 				"snps,u2ss_inp3_quirk");
+		dwc->req_p1p2p3_quirk = of_property_read_bool(node,
+				"snps,req_p1p2p3_quirk");
 	} else if (pdata) {
 		dwc->maximum_speed = pdata->maximum_speed;
 		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
@@ -768,6 +773,7 @@
 		dwc->disable_scramble_quirk = pdata->disable_scramble_quirk;
 		dwc->u2exit_lfps_quirk = pdata->u2exit_lfps_quirk;
 		dwc->u2ss_inp3_quirk = pdata->u2ss_inp3_quirk;
+		dwc->req_p1p2p3_quirk = pdata->req_p1p2p3_quirk;
 	}
 
 	/* default to superspeed if no maximum_speed passed */