From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org, Hans de Goede <hdegoede@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Walleij <linus.walleij@linaro.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Biju Das <biju.das@bp.renesas.com>,
Badhri Jagan Sridharan <badhri@google.com>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
linux-mediatek@lists.infradead.org,
Min Guo <min.guo@mediatek.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
linux-arm-kernel@lists.infradead.org, Li Jun <jun.li@nxp.com>
Subject: Re: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by node
Date: Mon, 20 May 2019 11:03:59 +0300 [thread overview]
Message-ID: <20190520080359.GC1887@kuha.fi.intel.com> (raw)
In-Reply-To: <1558319951.10179.352.camel@mhfsdcap03>
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...
> > > > ---
> > > > v5 changes:
> > > > 1. remove linux/of.h suggested by Biju
> > > > 2. add tested by Biju
> > > >
> > > > Note: still depends on [1]
> > > > [1]: [v6,08/13] usb: roles: Introduce stubs for the exiting functions in role.h
> > > > https://patchwork.kernel.org/patch/10909971/
> > > >
> > > > v4 changes:
> > > > 1. use switch_fwnode_match() to find fwnode suggested by Heikki
> > > > 2. this patch now depends on [1]
> > > >
> > > > [1] [v6,08/13] usb: roles: Introduce stubs for the exiting functions in role.h
> > > > https://patchwork.kernel.org/patch/10909971/
> > > >
> > > > v3 changes:
> > > > 1. use fwnodes instead of node suggested by Andy
> > > > 2. rebuild the API suggested by Heikki
> > > >
> > > > v2 no changes
> > > > ---
> > > > drivers/usb/roles/class.c | 24 ++++++++++++++++++++++++
> > > > include/linux/usb/role.h | 8 ++++++++
> > > > 2 files changed, 32 insertions(+)
> > > >
> > > > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> > > > index f45d8df5cfb8..4a1f09a41ec0 100644
> > > > --- a/drivers/usb/roles/class.c
> > > > +++ b/drivers/usb/roles/class.c
> > > > @@ -135,6 +135,30 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
> > > > }
> > > > EXPORT_SYMBOL_GPL(usb_role_switch_get);
> > > >
> > > > +/**
> > > > + * fwnode_usb_role_switch_get - Find USB role switch by it's parent fwnode
> > > > + * @fwnode: The fwnode that register USB role switch
> > > > + *
> > > > + * Finds and returns role switch registered by @fwnode. The reference count
> > > > + * for the found switch is incremented.
> > > > + */
> > > > +struct usb_role_switch *
> > > > +fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
> > > > +{
> > > > + struct usb_role_switch *sw;
> > > > + struct device *dev;
> > > > +
> > > > + dev = class_find_device(role_class, NULL, fwnode, switch_fwnode_match);
> > > > + if (!dev)
> > > > + return ERR_PTR(-EPROBE_DEFER);
> > > > +
> > > > + sw = to_role_switch(dev);
> > > > + WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
> > > > +
> > > > + return sw;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
> >
> > This function only basically converts the fwnode to usb_role_switch,
> > but I would actually prefer that we walked through the device graph
> > here instead of expecting the caller to do that.
> >
> > So this function should probable be called fwnode_to_usb_role_switch()
> > and not fwnode_usb_role_switch_get(), but I guess you don't need it
> > at all, right?
> >
> >
> > thanks,
> >
>
--
heikki
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next prev parent reply other threads:[~2019-05-20 8:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-14 8:47 [v5 PATCH 0/6] add USB Type-B GPIO connector driver Chunfeng Yun
2019-05-14 8:47 ` [PATCH v5 1/6] dt-bindings: connector: add optional properties for Type-B Chunfeng Yun
2019-05-14 8:47 ` [PATCH v5 2/6] dt-bindings: usb: add binding for Type-B GPIO connector driver Chunfeng Yun
2019-05-14 18:12 ` Rob Herring
2019-05-15 9:36 ` Chunfeng Yun
2019-05-14 8:47 ` [PATCH v5 3/6] dt-bindings: usb: mtu3: add properties about USB Role Switch Chunfeng Yun
2019-05-14 18:17 ` Rob Herring
2019-05-14 8:47 ` [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by node Chunfeng Yun
2019-05-17 10:37 ` Heikki Krogerus
2019-05-17 13:05 ` Heikki Krogerus
2019-05-20 2:39 ` Chunfeng Yun
2019-05-20 8:03 ` Heikki Krogerus [this message]
2019-05-20 8:06 ` Biju Das
2019-05-20 8:36 ` Heikki Krogerus
2019-05-20 9:45 ` Biju Das
2019-05-21 7:35 ` Chunfeng Yun
2019-05-21 10:33 ` Heikki Krogerus
2019-05-22 3:37 ` Chunfeng Yun
2019-05-21 9:58 ` Heikki Krogerus
2019-05-22 8:05 ` Biju Das
2019-05-22 9:30 ` Chunfeng Yun
2019-05-22 10:55 ` Biju Das
2019-05-22 14:26 ` Heikki Krogerus
2019-05-22 14:57 ` Biju Das
2019-05-24 12:44 ` Heikki Krogerus
2019-05-27 3:08 ` Chunfeng Yun
2019-05-28 6:52 ` Biju Das
2019-05-28 9:23 ` Chunfeng Yun
2019-05-23 10:16 ` Chunfeng Yun
2019-05-24 11:40 ` Heikki Krogerus
2019-05-27 3:07 ` Chunfeng Yun
2019-05-27 10:45 ` Heikki Krogerus
2019-05-14 8:47 ` [PATCH v5 5/6] usb: roles: add USB Type-B GPIO connector driver Chunfeng Yun
2019-05-20 8:31 ` Heikki Krogerus
2019-05-21 7:44 ` Chunfeng Yun
2019-05-14 8:47 ` [PATCH v5 6/6] usb: mtu3: register a USB Role Switch for dual role mode Chunfeng Yun
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