Hi,
> On Thu, Oct 13, 2011 at 12:50:55PM +0530, Gupta, Ajay Kumar wrote:
> > We are facing an issue in AM335x based custom board which has two musb
> > port.
> >
> > a) musb0 ID pin is floating and have micro-B plug receptacle
> > connector. [DEVICE ONLY]
> > b) musb1 ID pin is grounded and have standard-A plug receptacle
> > connector. [HOST ONLY]
> >
> > We are using udc-core in linux v3.1-rc8 kernel. This kernel only
> > provides option for selecting gadget driver for first instance only as
> > builtin.
>
> why don't you mark all gadget drivers as modules ? I do that all the
> time:
This wouldn't help if we want to use musb1 (host only) port during bootup
so that root file system on a pen drive connected to it can be mounted.
>
> CONFIG_USB_GADGET=m
> CONFIG_USB_GADGET_DEBUG=y
> CONFIG_USB_GADGET_DEBUG_FILES=y
> CONFIG_USB_GADGET_DEBUG_FS=y
> CONFIG_USB_GADGET_VBUS_DRAW=2
> CONFIG_USB_R8A66597=m
> CONFIG_USB_M66592=m
> CONFIG_USB_AMD5536UDC=m
> CONFIG_USB_CI13XXX_PCI=m
> CONFIG_USB_NET2272=m
> CONFIG_USB_NET2272_DMA=y
> CONFIG_USB_NET2280=m
> CONFIG_USB_GOKU=m
> CONFIG_USB_EG20T=m
> CONFIG_USB_DUMMY_HCD=m
> CONFIG_USB_GADGET_DUALSPEED=y
> CONFIG_USB_GADGET_SUPERSPEED=y
> CONFIG_USB_ZERO=m
> CONFIG_USB_ZERO_HNPTEST=y
> CONFIG_USB_AUDIO=m
> CONFIG_USB_ETH=m
> CONFIG_USB_ETH_RNDIS=y
> CONFIG_USB_ETH_EEM=y
> CONFIG_USB_G_NCM=m
> CONFIG_USB_GADGETFS=m
> CONFIG_USB_FUNCTIONFS=m
> CONFIG_USB_FUNCTIONFS_ETH=y
> CONFIG_USB_FUNCTIONFS_RNDIS=y
> CONFIG_USB_FUNCTIONFS_GENERIC=y
> CONFIG_USB_FILE_STORAGE=m
> CONFIG_USB_FILE_STORAGE_TEST=y
> CONFIG_USB_MASS_STORAGE=m
> CONFIG_USB_G_SERIAL=m
> CONFIG_USB_MIDI_GADGET=m
> CONFIG_USB_G_PRINTER=m
> CONFIG_USB_CDC_COMPOSITE=m
> CONFIG_USB_G_NOKIA=m
> CONFIG_USB_G_MULTI=m
> CONFIG_USB_G_MULTI_RNDIS=y
> CONFIG_USB_G_MULTI_CDC=y
> CONFIG_USB_G_HID=m
> CONFIG_USB_G_DBGP=m
> # CONFIG_USB_G_DBGP_PRINTK is not set
> CONFIG_USB_G_DBGP_SERIAL=y
> CONFIG_USB_G_WEBCAM=m
>
> > Current musb driver requires a gadget module to be inserted for a musb
> > port to be usable in OTG mode which is the only mode available in
> > v3.1-rc8 due to recent changes removing all HOST and GADGET only
> > ifdeffery.
>
> You can add runtime checks based on platform_data. Something like:
>
> switch (pdata->mode) {
> case MUSB_HOST:
> start_host();
> break;
> case MUSB_PERIPHERAL:
> start_gadget();
> break;
> case MUSB_OTG:
> start_gadget()
> start_host();
> break;
> default:
> error();
> }
>
> which means that for a port which is host-only, it won't require a
> gadget driver and for a port which is gadget-only, it won't start host
> stack.
If so then how about the menuconfig option for gadget driver for such host
only port? Shouldn't the gadget driver option be unavailable for such ports?
>
> > Now for the custom board's musb1 port to be usable we have two option:
> > 1) After bootup insert a gadget module and then use host
> functionality.
> > 2) Change the menuconfig logic and possibly udc-core layer so that it
> provides option
> > to select second gadget module as builtin.
>
> why built-in ?
Already explained above.
>
> > 3) Change musb driver so that there is no need for gadget driver for
> > host only ports. (may be based on musb->board_mode ?)
>
> yes.
Doesn't seem to be a cleaner way as explained above the issue of gadget
Driver coming in menuconfig for such ports.
Ajay
>
> > In there any plan to support option 2) or 3) above?
> >
> > Now the issue on our custom board is that we want root filesystem on
> > MSC pen drive connected to musb1 port and this gadget limitation is
> > stopping us to support this.
>
> well, patches are welcome ;-)
>
> --
> balbi
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