[PATCH] usb: Make sure usb/phy/of gets built-in

[Alexey.Brodkin@synopsys.com (Alexey Brodkin)]

Hello,

On Tue, 2017-04-18@12:23 +0000, Alexey Brodkin wrote:
> Hello Frank,
> 
> On Mon, 2017-04-17@20:15 -0700, Frank Rowand wrote:
> > 
> > On 04/13/17 05:33, Alexey Brodkin wrote:
> > > 
> > > 
> > > DWC3 driver uses of_usb_get_phy_mode() which is
> > > implemented in drivers/usb/phy/of.c and in bare minimal
> > > configuration it might not be pulled in kernel binary.
> > > 
> > > In case of ARC or ARM this could be easily reproduced with
> > > "allnodefconfig" +CONFIG_USB=m +CONFIG_USB_DWC3=m.
> > > 
> > > On building all ends-up with:
> > > ---------------------->8------------------
> > > ? Kernel: arch/arm/boot/Image is ready
> > > ? Kernel: arch/arm/boot/zImage is ready
> > > ? Building modules, stage 2.
> > > ? MODPOST 5 modules
> > > ERROR: "of_usb_get_phy_mode" [drivers/usb/dwc3/dwc3.ko] undefined!
> > > make[1]: *** [__modpost] Error 1
> > > make: *** [modules] Error 2
> > > ---------------------->8------------------
> > > 
> > > Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com>
> > > Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> > > Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
> > > Cc: Geert Uytterhoeven <geert+renesas at glider.be>
> > > Cc: Nicolas Pitre <nicolas.pitre at linaro.org>
> > > Cc: Thomas Gleixner <tglx at linutronix.de>
> > > Cc: Felipe Balbi <balbi at kernel.org>
> > > Cc: Felix Fietkau <nbd at nbd.name>
> > > Cc: Jeremy Kerr <jk at ozlabs.org>
> > > Cc: linux-snps-arc at lists.infradead.org
> > > Cc: stable at vger.kernel.org
> > > ---
> > > ?drivers/Makefile | 1 +
> > > ?1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/Makefile b/drivers/Makefile
> > > index 2eced9afba53..8f8bdc9e3d29 100644
> > > --- a/drivers/Makefile
> > > +++ b/drivers/Makefile
> > > @@ -104,6 +104,7 @@ obj-$(CONFIG_USB_PHY)		+= usb/
> > > ?obj-$(CONFIG_USB)		+= usb/
> > > ?obj-$(CONFIG_PCI)		+= usb/
> > > ?obj-$(CONFIG_USB_GADGET)	+= usb/
> > 
> > > 
> > > 
> > > +obj-$(CONFIG_OF)		+= usb/
> > 
> > Would CONFIG_USB_SUPPORT make more sense? (And does it work?)
> 
> Well I'm not really sure here.
> 
> The problem was in missing "drivers/usb/phy/of.o" in "drivers/usb/built-in.o".
> So I took a look at how components get enabled and saw quite mixed stuff.
> 
> In "drivers/usb/phy/Makefile" we see:
> ------------------------->8---------------------------
> obj-$(CONFIG_OF)????????????????????????+= of.o
> ------------------------->8---------------------------
> 
> In "drivers/usb/Makefile" we see:
> ------------------------->8---------------------------
> obj-$(CONFIG_USB_SUPPORT)???????+= phy/
> ------------------------->8---------------------------
> 
> From above I may conclude that your proposal should work as well
> but it's more a question of which approach is safer and more future proof.
> 
> Maybe it even worth adding the following to "drivers/usb/Makefile":
> ------------------------->8---------------------------
> obj-$(CONFIG_USB_SUPPORT)???????+= phy/
> ------------------------->8---------------------------

I'm wondering if there're any other thoughts on this one?
The patch fixes a real problem and it would be good to get this or similar
fix upstream.

-Alexey