ARM: dts: dra7: Disable USB metastability workaround for USB2

The metastability workaround causes Erratic errors [1]
on the HighSpeed USB PHY which can cause upto 2 seconds
delay in enumerating to a USB host while in Gadget mode.

Disable the Run/Stop metastability workaround to avoid this
ill effect. We are aware that this opens up the opportunity
for Run/Stop metastability, however this issue has never been
observed in TI releases so we think that Run/Stop metastability
is a lesser evil than the PHY Erratic errors. So disable it.

[1] USB controller trace during gadget enumeration
    irq/90-dwc3-969   [000] d...    52.323145: dwc3_event: event
    (00000901): Erratic Error [U0]
    irq/90-dwc3-969   [000] d...    52.560646: dwc3_event: event
    (00000901): Erratic Error [U0]
    irq/90-dwc3-969   [000] d...    52.798144: dwc3_event: event
    (00000901): Erratic Error [U0]

Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Felipe Balbi <felipe.balbi@linux/intel.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
index ac9216293b7c74283351f67c05f76bb59dbd52e0..947ce588a35b2c7461dccbaef1e8d31e55ec1fa2 100644 (file)
--- a/arch/arm/boot/dts/dra7.dtsi
+++ b/arch/arm/boot/dts/dra7.dtsi
@@ -1547,6 +1547,7 @@
                                dr_mode = "otg";
                                snps,dis_u3_susphy_quirk;
                                snps,dis_u2_susphy_quirk;
+                               snps,dis_metastability_quirk;
                        };
                };