Commit bc83a877 authored by Ran Wang's avatar Ran Wang Committed by Greg Kroah-Hartman
Browse files

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: default avatarRan Wang <ran.wang_1@nxp.com>
Reviewed-by: default avatarPeter Chen <peter.chen@nxp.com>
Signed-off-by: default avatarFrank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240124152525.3910311-3-Frank.Li@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c35ba0ac

Documentation/devicetree/bindings/usb/snps,dwc3.yaml

+7 −0
Original line number Diff line number Diff line
@@ -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