[Bug 225713] Zynq/Zedboard GPIO driver can reset USB port on some boards

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=225713

            Bug ID: 225713
           Summary: Zynq/Zedboard GPIO driver can reset USB port on some
                    boards
           Product: Base System
           Version: CURRENT
          Hardware: arm
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: arm
          Assignee: freebsd-arm at FreeBSD.org
          Reporter: thoma555-bsd at yahoo.com

Created attachment 190368
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=190368&action=edit
patch for sys/arm/xilinx/zy7_gpio.c

The Zynq/Zedboard GPIO driver attempts to tri-state all GPIO pins on boot up
but the order in which I reset the hardware can cause the pins to be briefly
held low before being tri-stated.  This is a problem on boards that use GPIO
pins to reset devices.

In particular, the Zybo and ZC-706 boards use a GPIO pin as a USB PHY reset. 
If U-boot enables the USB port before booting the kernel, the GPIO driver
attach causes a glitch on the USB PHY reset and the USB port loses power.  My
fix is to have the GPIO driver leave the pins in whatever configuration U-boot
placed them.

-- 
You are receiving this mail because:
You are the assignee for the bug.