Re: [PATCH v2 4/6] usb: roles: add API to get usb_role_switch by node

[Heikki Krogerus]

On Fri, Mar 15, 2019 at 05:32:59PM +0800, Chunfeng Yun wrote:
> Hi,
> On Fri, 2019-03-15 at 11:26 +0200, Heikki Krogerus wrote:
> > Hi Chunfeng,
> > 
> > On Fri, Mar 15, 2019 at 05:13:24PM +0800, Chunfeng Yun wrote:
> > > I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,
> > > 
> > > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
> > > ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
> > > `usb_role_switch_register'
> > > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
> > > ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
> > > `usb_role_switch_unregister'
> > 
> > So you need to add dependency on USB_ROLE_SWITCH, right?
> Yes
> 
> > 
> > --- a/drivers/usb/mtu3/Kconfig
> > +++ b/drivers/usb/mtu3/Kconfig
> > @@ -43,6 +43,7 @@ config USB_MTU3_DUAL_ROLE
> >         bool "Dual Role mode"
> >         depends on ((USB=y || USB=USB_MTU3) && (USB_GADGET=y || USB_GADGET=USB_MTU3))
> >         depends on (EXTCON=y || EXTCON=USB_MTU3)
> > +       depends on USB_ROLE_SWITCH
> >         help
> >           This is the default mode of working of MTU3 controller where
> >           both host and gadget features are enabled.
> > 
> > > the following patch has fixed the issue, but seems not get into kernel,
> > > [v3,08/12] usb: roles: Add usb role switch notifier.
> > > https://patchwork.kernel.org/patch/10836525/
> > 
> > I don't understand how that fixes the problem? That patch will in any
> > case be targeting v5.2. We are in the middle of merge window, so
> > nothing is happening until v5.1-rc1 is tagged.
> It provides some dummy inline functions when USB_ROLE_SWITCH is not
> enabled, this will avoid build error

Ah, true. Those should brobable be introduced in their own patch.


thanks,

-- 
heikki