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

[Heikki Krogerus]

On Mon, May 20, 2019 at 08:06:41AM +0000, Biju Das wrote:
> Hi Heikki,
> 
> > -----Original Message-----
> > From: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > Sent: Monday, May 20, 2019 9:04 AM
> > To: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Greg Kroah-Hartman
> > <gregkh@xxxxxxxxxxxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx>;
> > Matthias Brugger <matthias.bgg@xxxxxxxxx>; Adam Thomson
> > <Adam.Thomson.Opensource@xxxxxxxxxxx>; Li Jun <jun.li@xxxxxxx>;
> > Badhri Jagan Sridharan <badhri@xxxxxxxxxx>; Hans de Goede
> > <hdegoede@xxxxxxxxxx>; Andy Shevchenko
> > <andy.shevchenko@xxxxxxxxx>; Min Guo <min.guo@xxxxxxxxxxxx>;
> > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> > usb@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> > mediatek@xxxxxxxxxxxxxxxxxxx; Biju Das <biju.das@xxxxxxxxxxxxxx>; Linus
> > Walleij <linus.walleij@xxxxxxxxxx>
> > 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@xxxxxxxxxxxx>
> > > > > > Tested-by: Biju Das <biju.das@xxxxxxxxxxxxxx>
> > > > >
> > > > > Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > > >
> > > > 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