On Tue, May 21, 2019 at 03:35:04PM +0800, Chunfeng Yun wrote: > Hi, > On Mon, 2019-05-20 at 09:45 +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 > > > > For eg:- > > > > hd3ss3220@47 { > > compatible = "ti,hd3ss3220"; > > ... > > .... > > usb_con: connector { > > .... > > .... > > port { > > hd3ss3220_ep: endpoint@0 { > > reg = <0>; > > remote-endpoint = <&usb3peri_role_switch>; > > }; > > }; > > }; > > }; > > > > Regards, > > Biju > > I tested 3 cases: > > case 1: > > connector { > compatible = "linux,typeb-conn-gpio", "usb-b-connector"; > label = "micro-USB"; > type = "micro"; > id-gpios = <&pio 12 GPIO_ACTIVE_HIGH>; > vbus-supply = <&usb_p0_vbus>; > > port { > bconn_ep: endpoint@0 { > remote-endpoint = <&usb_role_sw>; > }; > }; > }; > > &mtu3 { > usb-role-switch; > > port { > usb_role_sw: endpoint@0 { > remote-endpoint = <&bconn_ep>; > }; > }; > }; > > the driver of connector could use usb_role_switch_get(dev) to get > mtu3's USB Role Switch. (dev is the device of connector) > > case 2: > > &mtu3 { > usb-role-switch; > > connector { > compatible = "linux,typeb-conn-gpio", "usb-b-connector"; > label = "micro-USB"; > type = "micro"; > id-gpios = <&pio 12 GPIO_ACTIVE_HIGH>; > vbus-supply = <&usb_p0_vbus>; > }; > }; > > the driver of connector using usb_role_switch_get(dev) failed to get > mtu3's USB Role Switch. > error log: > #OF: graph: no port node found in /usb@11271000/connector > this is because connector hasn't child node connected to remote > endpoint which register USB Role Switch > > case 3: > > rsw_iddig: role_sw_iddig { > compatible = "linux,typeb-conn-gpio"; > status = "okay"; > > connector { > compatible = "usb-b-connector"; > label = "micro-USB"; > type = "micro"; > id-gpios = <&pio 12 GPIO_ACTIVE_HIGH>; > vbus-supply = <&usb_p0_vbus>; > > port { > bconn_ep: endpoint@0 { > remote-endpoint = <&usb_role_sw>; > }; > }; > }; > }; > > &mtu3 { > usb-role-switch; > > port { > usb_role_sw: endpoint@0 { > remote-endpoint = <&bconn_ep>; > }; > }; > }; > > > the driver of connector using usb_role_switch_get(dev) also failed to > get mtu3's USB Role Switch. Because usb_role_switch_get() only search > its child nodes (connector node), but not child's child (port node) > This case is the same as Biju's > > Usually type-c is similar with case 3; > the next version v6 of this series will use case 2 as Rob suggested, > see [v5, 2/6] > > for case 2, will need the new API fwnode_usb_role_switch_get(); Thanks for the explanation. In this case, if I understood this correctly, the USB controller, which is also the role switch, is the parent of the connector. So shouldn't we simply consider that in the current API? diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c index f45d8df5cfb8..2f898167b99a 100644 --- a/drivers/usb/roles/class.c +++ b/drivers/usb/roles/class.c @@ -125,6 +125,13 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev) { struct usb_role_switch *sw; + /* + * Simplest case is that a connector is looking for the controller, + * which is its parent. + */ + if (device_property_present(dev->parent, "usb-role-switch")) + return to_role_switch(dev->parent); + sw = device_connection_find_match(dev, "usb-role-switch", NULL, usb_role_switch_match); > for case 3, use the new API, or need modify usb_role_switch_get(); I did not completely understand this case, but isn't it the same as case 2 in the end, after you change it as Rob suggested? thanks, -- heikki
