Re: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by node

Heikki Krogerus
2019-05-20T08:36:10Z

On Mon, May 20, 2019 at 08:06:41AM +0000, Biju Das wrote:
> Hi Heikki,
>
> > -----Original Message-----
> > From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > Sent: Monday, May 20, 2019 9:04 AM
> > To: Chunfeng Yun <chunfeng.yun@mediatek.com>
> > Cc: Rob Herring <robh+dt@kernel.org>; Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org>; Mark Rutland <mark.rutland@arm.com>;
> > Matthias Brugger <matthias.bgg@gmail.com>; Adam Thomson
> > <Adam.Thomson.Opensource@diasemi.com>; Li Jun <jun.li@nxp.com>;
> > Badhri Jagan Sridharan <badhri@google.com>; Hans de Goede
> > <hdegoede@redhat.com>; Andy Shevchenko
> > <andy.shevchenko@gmail.com>; Min Guo <min.guo@mediatek.com>;
> > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-
> > usb@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> > mediatek@lists.infradead.org; Biju Das <biju.das@bp.renesas.com>; Linus
> > Walleij <linus.walleij@linaro.org>
> > Subject: Re: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by
> > node
> >
> > On Mon, May 20, 2019 at 10:39:11AM +0800, Chunfeng Yun wrote:
> > > Hi,
> > > On Fri, 2019-05-17 at 16:05 +0300, Heikki Krogerus wrote:
> > > > Hi,
> > > >
> > > > On Fri, May 17, 2019 at 01:37:36PM +0300, Heikki Krogerus wrote:
> > > > > On Tue, May 14, 2019 at 04:47:21PM +0800, Chunfeng Yun wrote:
> > > > > > Add fwnode_usb_role_switch_get() to make easier to get
> > > > > > usb_role_switch by fwnode which register it.
> > > > > > It's useful when there is not device_connection registered
> > > > > > between two drivers and only knows the fwnode which register
> > > > > > usb_role_switch.
> > > > > >
> > > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> > > > > > Tested-by: Biju Das <biju.das@bp.renesas.com>
> > > > >
> > > > > Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > > >
> > > > Hold on. I just noticed Rob's comment on patch 2/6, where he points
> > > > out that you don't need to use device graph since the controller is
> > > > the parent of the connector. Doesn't that mean you don't really need
> > > > this API?
> > > No, I still need it.
> > > The change is about the way how to get fwnode; when use device graph,
> > > get fwnode by of_graph_get_remote_node(); but now will get fwnode by
> > > of_get_parent();
> >
> > OK, I get that, but I'm still not convinced about if something like this function
> > is needed at all. I also have concerns regarding how you are using the
> > function. I'll explain in comment to the patch 5/6 in this series...
>
> FYI, Currently I am also using this api in my patch series.
> https://patchwork.kernel.org/patch/10944637/

Yes, and I have the same question for you I jusb asked in comment I
added to the patch 5/6 of this series. Why isn't usb_role_switch_get()
enough?

thanks,

--
heikki