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? > It looks like we have an issue somewhere in the code, and instead of fixing > that, you are working around it. Let's not do that. OK. Regards, Biju
