[PATCH v4 0/3] initialize (multiple) PHYs in xhci-plat

Tue Oct 3 01:15:44 PDT 2017

On Mon, 2017-10-02 at 14:44 +0200, Greg KH wrote:
> On Mon, Oct 02, 2017 at 02:35:08PM +0200, Jerome Brunet wrote:
> > On Sun, 2017-10-01 at 22:32 +0200, Martin Blumenstingl wrote:
> > > Hello Greg, Hello Mathias,
> > > 
> > > On Mon, Sep 18, 2017 at 10:49 AM, Greg KH <gregkh at linuxfoundation.org>
> > > wrote:
> > > > On Sun, Sep 17, 2017 at 10:51:31PM +0200, Martin Blumenstingl wrote:
> > > > > Hello Mathias, Hello Greg,
> > > > > 
> > > > > On Sun, Sep 3, 2017 at 11:38 PM, Martin Blumenstingl
> > > > > <martin.blumenstingl at googlemail.com> wrote:
> > > > > > This series is the outcome of a discussion with Felipe Balbi,
> > > > > > see [0] and [1].
> > > > > > The quick-summary of this is:
> > > > > > - dwc3 already takes one USB2 and one USB3 PHY and initializes these
> > > > > >   correct
> > > > > > - some other HCI platform drivers (like ehci-platform.c, xhci-mtk.c
> > > > > > and
> > > > > >   ohci-platform.c) do not have a limitation on the number of PHYs -
> > > > > > they
> > > > > >   support one PHY per actual host port
> > > > > > - Amlogic Meson GXL and GXM SoCs come with a dwc3 IP block which has
> > > > > > two
> > > > > >   or three USB2 ports enabled on the internal root-hub. The SoCs
> > > > > > also
> > > > > >   provide separate USB2 PHYs, one per port. All USB2 PHYs (which are
> > > > > >   internally "connected" to the dwc3 roothub) need to be powered on,
> > > > > >   otherwise USB devices cannot be enumerated (even if just one PHY
> > > > > > is
> > > > > >   disabled and if the device is plugged into another, enabled port)
> > > > > > 
> > > > > > In my first attempt to get USB supported on the GXL and GXM SoCs I
> > > > > > tried
> > > > > > to work-around the problem that I could not pass multiple PHYs to
> > > > > > the
> > > > > > dwc3 controller.
> > > > > > This was rejected by Rob Herring (which was definitely the thing to
> > > > > > do
> > > > > > in
> > > > > > my opinion), see [2]
> > > > > > 
> > > > > > This series adds a new "platform-roothub". This can be configured
> > > > > > through
> > > > > > devicetree by passing a child-node with "reg = <0>" to the USB
> > > > > > controller. Additionally there has to be a child-node for each port
> > > > > > on
> > > > > > the root-hub. Each of the child-nodes takes a "phys" and "phy-names"
> > > > > > property. This allows modeling the root-hub in devicetree similar to
> > > > > > the
> > > > > > USB device binding (documented in devicetree/bindings/usb/usb-
> > > > > > device.txt)
> > > > > > This avoids and backwards-compatibility problems (which was a
> > > > > > concern
> > > > > > regardless of the solution, see [3]) since the binding for the root-
> > > > > > hub
> > > > > > was previously not specified (and we're not using the "phys"
> > > > > > property of
> > > > > > the controller, which might have served different purposes before,
> > > > > > depending on the drivers).
> > > > > > 
> > > > > > Additionally this integrates the new platform-roothub into xhci-
> > > > > > plat.c
> > > > > > which automatically enables it for the dwc3 driver (in host-mode).
> > > > > > 
> > > > > > 
> > > > > > Changes since RFCv3 at [6]:
> > > > > > - moved the DT binding change from patch #3 to patch #1 as suggested
> > > > > >   by Rob Herring (and slightly adjusted the commit message to
> > > > > > account
> > > > > >   for that)
> > > > > > - added Tested-by from Chunfeng Yun (who confirmed that the whole
> > > > > >   concept and implementation works fine on Mediatek SoCs - many
> > > > > > thanks
> > > > > >   again!) to patch #2
> > > > > > - added Rob Herring's ACK to patches 1 and 3
> > > > > > - dropped RFC status (RFCv3 -> PATCH v4)
> > > > > 
> > > > > I just wanted to rebase this to v4.14-rc1 (now that this is out) -
> > > > > however I noticed that v4 still applies to v4.14-rc1 cleanly (the
> > > > > patches are still identical to v4 after rebasing).
> > > > > 
> > > > > we have an ACK from the devicetree maintainers and a "Tested-by" for a
> > > > > Mediatek (= non-Amlogic) SoC.
> > > > > I already have patches for the Amlogic GXL/GXM platforms queued, those
> > > > > are just waiting on this series.
> > > > > 
> > > > > what is still missing to get this series into v4.15?
> > > > 
> > > > Well, we couldn't do anything until 4.14-rc1 is out, now that it is, let
> > > > us catch up on patch review please...
> > > 
> > > OK, I understand that.
> > > please let me know once you've caught up with the review backlog - as
> > > I said I would like to get this into 4.15 if nothing else comes up
> > > during the code-review
> > 
> > This series works well on the libretech-cc (le potato)
> > For the series:
> > 
> > Tested-by: Jerome Brunet <jbrunet at baylibre.com>
> 
> Hey, I have one of those boards now, was just about to try to get it to
> work.  Is this series necessary for it to run properly on 4.14-rc?

To run w/o usb, no. It should already be decent on 4.14-rc.
To run with usb, you need this series and:

* the usb3 phy driver sent but (I believe) not yet merged [0]
* A few DT changes enable the whole thing.

The whole thing is available here [1]

However, while you were at KR2017, we found an unrelated, yet very annoying,
issue which may trigger "Synchronous External Aborts" ... The whole story is
available here [2] and the work around patch is available here [3].

If you have downloaded your image from here [4], the kernel is a v4.13 plus
* few changes already merged in next or under review (cec, mmc, usb, ...)
* Overlay support 
* WIP for the hdmi audio.
Sources are here [5]

[0]: https://lkml.kernel.org/r/20170924195000.13276-1-martin.blumenstingl@google
mail.com
[1]: https://github.com/libre-computer-project/libretech-linux/commits/linux-4.1
3/usb
[2]: https://lkml.kernel.org/r/1507017860.17300.106.camel@baylibre.com
[3]: https://github.com/libre-computer-project/libretech-linux/commit/0f71f762a9
c37ab423e0c9e0498081a9a17f2b8a
[4]: http://baylibre.com/kernel-recipes-mainline-aml-s905x-cc-le-potato/
[5]: https://github.com/libre-computer-project/libretech-linux/commits/linux-4.1
3/libretech-cc-overlays

> 
> thanks,
> 
> greg k-h