Re: [RFC 0/8] Add support for NVIDIA Tegra XUSB

[Martyn Welch]

On 02/11/15 17:27, Andrew Bresticker wrote:
> Hi Martyn,
>
> On Mon, Nov 2, 2015 at 3:55 AM, Martyn Welch
> <martyn.welch@xxxxxxxxxxxxxxx> wrote:
> > This series is based on commits that can be found in the git tree here:
> >
> > https://github.com/thierryreding/linux/commits/staging/xhci
> >
> > I have included the patches I've used from that tree as patches 1-5.
> >
> > The above patches were submitted for review back in May:
> >
> > https://lkml.org/lkml/2015/5/4/574
> >
> > The approach taken in these patches was deemed not appropriate (treating
> > the XUSB as a MFD).
> >
> > In patch 6 I add the bindings based in those submitted for review here
> > (with a few modifications currently required by the driver):
> >
> > https://www.spinics.net/lists/linux-usb/msg130940.html
> >
> > I have included my changes to the original patch series in patch 7. With
> > these modifications the patch series builds and works, but is rather hacky.
> > Devices for the mailbox driver and xHCI driver are now created in the xusb
> > driver (still under the mfd directory for now - it will be moved before
> > this series is submitted properly). As the child devices use
> > infrastructure which expects the device to be associated with a of_node,
> > it has been necessary to point the child device at the parents of_node
> > where this is needed. This approach did not seem viable for the mailbox
> > API, so to get that working the child device node was pointed to the
> > parents of_node (in tegra_xusb_add_device). The unfortunate side effect of
> > this is that upon device creation the parents probe routine gets called...
> >
> > Not good.
> >
> > Patch 8 attempts to resolve this. When passing the parents device node to
> > the mailbox API, the mailbox's receive callback was raising errors as
> > that function is looking for the drvdata stored in the child's device node,
> > but getting the parents. This patch jumps though a few hoops to get to the
> > child's device node.
> After my last submission, we had a discussion about the mailbox and
> decided not to use the mailbox framework and instead use a private API
> between the xHCI driver and the XUSB_PADCTL driver.

Ok.

> > Unfortunately, whilst the receive callback seems to be getting the right
> > drvdata, USB3 devices are being enumerated as USB2 devices rather than
> > USB3 devices, so something is clearly not right.
> Tegra124?  Tegra210?  Which board?

Tegra124, nyan-blaze.

Martyn

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