Re: RFC: Platform data for onboard USB assets

Benjamin Herrenschmidt
2011-03-11T21:52:43Z

On Fri, 2011-03-11 at 09:50 +0000, Andy Green wrote:
> Hi -
>
> platform_data is a well established way in Linux to pass configuration
> data up to on-board assets from a machine file like mach-xyz.c. It's
> also supported to pass platform_data up to devices that are probed
> asynchronously from busses like i2c as well, which is very handy.

.../...

That looks like something the device-tree would deal with nicely :-)

Cheers,
Ben.

> However AFAIK it's not possible to bind platform_data to probed USB
> devices as it stands.
>
> There are now boards which have on-board USB assets, for example OMAP4
> Panda which has a USB <-> Ethernet bridge wired up permanently. It'd be
> convenient to also be able to pass optional platform_data to these
> devices when they are asynchronously probed.
>
> So what's the feeling about a new api to register an array of
> platform_data pointers bound to static "devpath" names in the machine file?
>
> When a usb device is instantiated, it can check through this array if it
> exists, matching on devname, and attach the platform_data to the
> underlying probed usb device's dev->platform_data, which it seems is
> currently unused.
>
> The particular use that suggested this is on Panda, it would be ideal to
> be able to set a flag in the usb device's platform data that forces it
> to be named eth%d since it's a hardwired asset on the board with an RJ45
> socket.
>
> Comments, implementation suggestions, enquiries as to my level of crack
> consumption etc welcomed ^^
>
> -Andy
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/