[U-Boot] Query on the ci_udc driver for USB client implementation

[Marek Vasut]

On Monday, November 03, 2014 at 04:46:48 PM, Fabio Estevam wrote:
> On Mon, Nov 3, 2014 at 3:33 AM, Sanchayan Maity
> 
> <maitysanchayan at gmail.com> wrote:
> > Hello,
> > 
> > Any pointers?
> 
> Adding Marek and Stefan on Cc in case they can provide some help.
> 
> Regards,
> 
> Fabio Estevam
> 
> > Thanks & Regards,
> > Sanchayan Maity.
> > 
> > On Thursday 30 October 2014 11:14 AM, Sanchayan Maity wrote:
> >> Hello,
> >> 
> >> I am currently implementing USB Host and client support for Freescale
> >> Vybrid platform in u-boot. I managed to get the host implementation
> >> working.
> >> 
> >> For the host side, usb start calls usb_init(), which in turns call,
> >> usb_lowlevel_init(), from there into the ehic_hcd_init() of my
> >> implementation. So, setting up the necessary clocks and plls for USB in
> >> my implementation and then setting up the usb_ehci, ehci_hccr and
> >> echi_hcor structures was all. The flow and setup required i was able to
> >> trace.
> >> 
> >> The USB client part is not clear to me. I was thinking i can use the
> >> ci_udc driver somehow to implement the client part. How can i use the
> >> ci_udc driver to implement client functionality?. From what i could
> >> see, the usb_gadget_driver_register() is suppose to be the first call.
> >> But, i couldn't trace from where this gets called or the flow and setup
> >> is suppose to be. OR Is a separate client driver required and nothing
> >> generic can be used akin to how it could be done for host?

See include/configs/sansa_fuze_plus.h , you need the gadget driver for the
function you want to implement , in this case it's ethernet for example
(selected via CONFIG_USB_ETH_CDC ).

An example of DFU/UMS can be found in include/configs/exynos4-common.h
and to activate those, you need to use the 'dfu' or 'ums' commands.

> >> Sorry if i am asking this question in the wrong place. I couldn't find
> >> anyone in the u-boot IRC channel nor find something similar to the
> >> kernel-newbies mailing list.

There isn't any, so ask away ;-)

> >> Hope i am asking the right questions.
[...]

Best regards,
Marek Vasut