[meta-xilinx] zedboard usb

[Mike Looijmans]

On 28-01-16 23:29, gmane at reliableembeddedsystems.com wrote:
> Hi,
>
> I currently have a 4.4 mainline kernel with a multi-v7 config plus a slightly
> patched u-boot 2016.01 running on my zedboard.
>
> I'm trying to connect some camera to the USB(OTG) port (via an adapter) which
> did not succeed so far;)
>
> What I managed to do is to connect a USB stick, in u-boot I do
>
> usb start
>
> and the info regarding the mass storage USB device and so on is passed to the
> Linux kernel, where it is visible then:
>
> root at multi-v7-ml:/sys/bus/usb# lsusb
> Bus 001 Device 002: ID 0951:1643 Kingston Technology DataTraveler G3
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> root at multi-v7-ml:/sys/bus/usb#
>
> Is it this really necessary to get u-boot involved?
>
> I mean can I skip "usb start" in u-boot and do something magical in the kernel
> to turn on usb (since I don't need my USB device in u-boot, but later when
> Linux runs)?

Something is definitely wrong with your systen, you should not need any 
bootloader support at all for USB, the kernel handles it all perfectly well.

If I read "usb" and "zedboard" in the same sentence, the answer is usually 
that the "reset" of the PHY is not properly performed. This reset is connected 
to the PL, and should be triggered from within the USB driver (make sure the 
PL is programmed then) or prior to loading it.



Kind regards,

Mike Looijmans
System Expert

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