dt-bindings: usb: dwc3: Add snps,host-vbus-glitches-quirk avoid vbus glitch

When DWC3 is set to host mode by programming register DWC3_GCTL, VBUS
(or its control signal) will turn on immediately on related Root Hub
ports. Then the VBUS will be de-asserted for a little while during xhci
reset (conducted by xhci driver) for a little while and back to normal.

This VBUS glitch might cause some USB devices emuration fail if kernel
boot with them connected. One SW workaround which can fix this is to
program all PORTSC[PP] to 0 to turn off VBUS immediately after setting
host mode in DWC3 driver(per signal measurement result, it will be too
late to do it in xhci-plat.c or xhci.c).

Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240124152525.3910311-3-Frank.Li@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
index 203a1eb66691f6f3ea69686e397bc5a986a830ba..8f5d250070c784b0ad7e07efd3128a8f20f26c0f 100644 (file)
--- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
@@ -273,6 +273,13 @@ properties:
       with an external supply.
     type: boolean
 
+  snps,host-vbus-glitches-quirk:
+    description:
+      When set, power off all Root Hub ports immediately after
+      setting host mode to avoid vbus (negative) glitch happen in later
+      xhci reset. And the vbus will back to 5V automatically when reset done.
+    type: boolean
+
   snps,is-utmi-l1-suspend:
     description:
       True when DWC3 asserts output signal utmi_l1_suspend_n, false when