RFC: Platform data for onboard USB assets

From: Andy Green
Date: Fri Mar 11 2011 - 04:50:48 EST


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.

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
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