[fedora-arm] [PATCH] kernel .config options to enable USB on a Wandboard (and other i.MX systems)

[Niels de Vos]

On Fri, Jul 12, 2013 at 10:27:59AM +0200, Niels de Vos wrote:
> On Fri, Jul 12, 2013 at 01:33:52AM -0500, Dennis Gilmore wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > On Thu, 11 Jul 2013 17:05:55 +0200
> > Niels de Vos <devos at fedoraproject.org> wrote:
> > 
> > > Hi Peter and others,
> > > 
> > > The following .config options make it possible to use USB on a
> > > Wandboard Duallite and likely other i.MX based boards. USB works for
> > > me after loading the modules manually:
> > > 
> > > [root at wandboard ~]# modprobe ci13xxx_imx
> > > [root at wandboard ~]# modprobe usbmisc_imx
> > > [root at wandboard ~]# dmesg
> > 
> > tested your scratch build on my wandboard quad i only had to load
> > usbmisc_imx as ci13xxx_imx was already loaded. I wonder if we need to
> > patch dracut to pull the module into the initramfs and it will just
> > work.
> 
> I think loading the modules should happen automatically and depends on 
> the dtb that is used. The ci13xxx_imx supports USB-OTG and there are 
> some references to that in the dtb for the Quad, but fewer for the 
> Duallite. At least, thats my understanding after a quick look.
> 
> Whatever should trigger loading if usbmisc-imx is unclear to me. Maybe 
> there should be an option to include the usbmisc_imx module in 
> ci13xxx_imx... Oh well, something to ponder about later. Ideas welcome!

The dtb and all are good. The usbmisc-imx module is only missing the 
alias information for automatic detection/loading. The table that 
contains this information in the module is not exported, and depmod does 
not generate the details, so that modprobe does not know to load the 
module. A one-line patch makes this work, and it seems that this already 
has been merged upstream too:
- http://thread.gmane.org/gmane.linux.usb.general/88501
  (commit-id in Linus' tree: 269b83dc9ce007efc4393e8a5b77f208a0e18e4a)

Cheers,
Niels