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

From: Biju Das
Date: Tue May 28 2019 - 02:56:24 EST

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Hi Chunfeng Yun,

+ Chen Yu

Thanks for the feedback.

> Subject: Re: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by
> node
>
> Hi Heikki & Biju,
> On Fri, 2019-05-24 at 15:44 +0300, Heikki Krogerus wrote:
> > On Wed, May 22, 2019 at 02:57:33PM +0000, Biju Das wrote:
> > > Hi Heikki,
> > >
> > > Thanks for the patch
> > >
> > > > Subject: Re: [PATCH v5 4/6] usb: roles: add API to get
> > > > usb_role_switch by node
> > > >
> > > > On Wed, May 22, 2019 at 10:55:17AM +0000, Biju Das wrote:
> > > > > Hi Chunfeng Yun,
> > > > >
> > > > > Thanks for the feedback.
> > > > >
> > > > > > Subject: RE: [PATCH v5 4/6] usb: roles: add API to get
> > > > > > usb_role_switch by node
> > > > > >
> > > > > > Hi Biju,
> > > > > > On Wed, 2019-05-22 at 08:05 +0000, Biju Das wrote:
> > > > > > > Hi Heikki,
> > > > > > >
> > > > > > > Thanks for the feedback.
> > > > > > >
> > > > > > > > Subject: Re: [PATCH v5 4/6] usb: roles: add API to get
> > > > > > > > usb_role_switch by node
> > > > > > > >
> > > > > > > > On Mon, May 20, 2019 at 09:45:46AM +0000, Biju Das wrote:
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Hi Heikki,
> > > > > > > > >
> > > > > > > > > Thanks for the feedback.
> > > > > > > > >
> > > > > > > > > > Subject: Re: [PATCH v5 4/6] usb: roles: add API to get
> > > > > > > > > > usb_role_switch by node
> > > > > > > > > >
> > > > > > > > > > On Mon, May 20, 2019 at 08:06:41AM +0000, Biju Das wrote:
> > > > > > > > > > > Hi Heikki,
> > > > > > > > > > >
> > > > > > > > > > > > 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?
> > > > > > > > >
> > > > > > > > > Currently no issue. It will work with this api as well,
> > > > > > > > > since the port node is
> > > > > > > > part of controller node.
> > > > > > > > > For eg:-
> > > > > > > > > https://patchwork.kernel.org/patch/10944627/
> > > > > > > > >
> > > > > > > > > However if any one adds port node inside the connector
> > > > > > > > > node, then this
> > > > > > > > api may won't work as expected.
> > > > > > > > > Currently I get below error
> > > > > > > > >
> > > > > > > > > [ 2.299703] OF: graph: no port node found in
> > > > > > > > /soc/i2c@e6500000/hd3ss3220@47
> > > > > > > >
> > > > > > > > We need to understand why is that happening?
> > > > > > > >
> > > > > > >
> > > > > > > Form the stack trace the parent node is
> > > > > > > "parent_node=hd3ss3220@47" ,
> > > > > > instead of the "connector" node.
> > > > > > > That is the reason for the above error.
> > > > > > >
> > > > > > > [ 2.442429] of_graph_get_next_endpoint.part.0+0x28/0x168
> > > > > > > [ 2.447889] of_fwnode_graph_get_next_endpoint+0x5c/0xb0
> > > > > > > [ 2.453267] fwnode_graph_get_next_endpoint+0x20/0x30
> > > > > > > [ 2.458374] device_connection_find_match+0x74/0x1a0
> > > > > > > [ 2.463399] usb_role_switch_get+0x20/0x28
> > > > > > > [ 2.467542] hd3ss3220_probe+0xc4/0x218
> > > > > > >
> > > > > > > The use case is
> > > > > > >
> > > > > > > &i2c0 {
> > > > > > > hd3ss3220@47 {
> > > > > > > compatible = "ti,hd3ss3220";
> > > > > > >
> > > > > > > usb_con: connector {
> > > > > > > compatible = "usb-c-connector";
> > > > > > > port {
> > > > > > > hd3ss3220_ep: endpoint {
> > > > > > > remote-endpoint =
> > > > > > <&usb3_role_switch>;
> > > > > > > };
> > > > > > > };
> > > > > > > };
> > > > > > > };
> > > > > > > };
> > > > > > >
> > > > > > > &usb3_peri0 {
> > > > > > > companion = <&xhci0>;
> > > > > > > usb-role-switch;
> > > > > > >
> > > > > > > port {
> > > > > > > usb3_role_switch: endpoint {
> > > > > > > remote-endpoint = <&hd3ss3220_ep>;
> > > > > > > };
> > > > > > > };
> > > > > > > };
> > > > > > >
> > > > > > > Q1) How do we modify the usb_role_switch_get() function to
> > > > > > > search
> > > > > > > Child(connector) and child's endpoint?
> > > > > > How about firstly finding connector node in
> > > > > > fwnode_graph_devcon_match(), then search each endpoint?
> > > > >
> > > > > I have done a quick prototyping with the changes you suggested
> > > > > and it
> > > > works.
> > > > >
> > > > > - struct fwnode_handle *ep;
> > > > > + struct fwnode_handle *ep,*child,*tmp = fwnode;
> > > > >
> > > > > - fwnode_graph_for_each_endpoint(fwnode, ep) {
> > > > > + child = fwnode_get_named_child_node(fwnode, "connector");
> > > > > + if (child)
> > > > > + tmp = child;
> > > > > +
> > > > > + fwnode_graph_for_each_endpoint(tmp, ep) {
> > > > >
> > > > > Form the stack trace the parent node is "parent_node= connector" .
> > > > >
> > > > > [ 2.440922] of_graph_get_next_endpoint.part.0+0x28/0x168
> > > > > [ 2.446381] of_fwnode_graph_get_next_endpoint+0x5c/0xb0
> > > > > [ 2.451758] fwnode_graph_get_next_endpoint+0x20/0x30
> > > > > [ 2.456866] device_connection_find_match+0x84/0x1c0
> > > > > [ 2.461888] usb_role_switch_get+0x20/0x28
> > > > >
> > > > > Heikki,
> > > > > Are you ok with the above changes?
> > > >
> > > > Doesn't that mean that if we made fwnode_usb_role_switch_get() the
> > > > way I proposed, there is no problem? You just find the "connector"
> > > > child node in your driver, and pass that to
> fwnode_usb_role_switch_get():
> > >
> > > Yes, That is correct.
> > >
> > > > struct fwnode_handle *connector;
> > > > ...
> > > > connector = device_get_named_child_node(&client->dev,
> "connector");
> > > > if (IS_ERR(connector))
> > > > <do something>
> > > >
> > > > hd3ss3220->role_sw = fwnode_usb_role_switch_get(connector);
> > > > ...
> > > >
> > > > The difference is that instead of just converting a device node of
> > > > an usb role switch to the usb role switch, it works just like
> > > > usb_role_switch_get(), just taking fwnode instead of device entry as
> parameter.
> > > >
> > > > I prepared the patches implementing fwnode_usb_role_switch_get()
> > > > the way I though it needs to work for my own tests. Please find
> > > > the patches attached.
> > >
> > > I have tested this patches and conform it works.
> > > Do you plan to post this patches to ML?
> >
> > Could make them part of this series?
> I'll do it, thanks

Just a suggestion, Do you think, is it worth to add the below patch[1] also part of this series? So that we have all common patches in this series.

"usb: roles: Introduce stubs for the exiting functions in role.h."
[1] https://patchwork.kernel.org/patch/10909971/

Regards,
Biju

Next message: Christoph Hellwig: "Re: [PATCH v6 0/5] prerequisites for device reserved local mem rework"
Previous message: Colin King: "[PATCH][next] qed: fix spelling mistake "inculde" -> "include""
In reply to: Chunfeng Yun: "Re: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by node"
Next in thread: Chunfeng Yun: "RE: [PATCH v5 4/6] usb: roles: add API to get usb_role_switch by node"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]