Re: RFC: Platform data for onboard USB assets

From: Andy Green
Date: Thu Mar 17 2011 - 19:22:12 EST

On 03/17/2011 10:33 PM, Somebody in the thread at some point said:
On Thursday 17 March 2011 22:47:36 Greg KH wrote:
Patches to fix this, for this specific PandaBoard controller are gladly
accepted. What's odd is this is explicitly a Linux development board,
so you would think that this could have been caught, and fixed, in the
hardware a long time ago, right?

The way everyone resolves this stuff is by patching their kernel

Well, that means that the device tree work is going to be useful here,
right? :)

I like the idea. Let's make this the first use case where a lot of

You changed your first opinion about tagging "dynamically probed devices" with what is effectively platform_data, cool.

people will want to have the device tree on ARM. The patch to the
driver to check for a mac-address property is trivial, and we
can probably come up with a decent way of parsing the device
tree for USB devices, after all there is an existing spec for
it (

It doesn't do it already then.

That spec you pointed to from 1998 is obviously going to be a whole subproject doing the binding, it seems to fingerprint devices by VID/PID if I understood it.

What's the plan for leveraging that level of generality on "dynamically probed devices"? I mean I know what I want to use this for and the platform_data scheme covers all the soldered-on-the-board cases fine.

Is there actually a need for sort of not platform_data but universal vid_pid_specific_usb_device_option_data coming from the board definition file or bootloader for *pluggable* usb devices? udev seems to be well established doing that already in a generic, not-platform-specific way that can go in all distros and so on nicely. Maybe this is just my impoverished imagination and people do want, say, some kinds of USB mice to operate at higher DPI or whatever when plugged in a specific board because it is that board.

BTW the whole RFC patchset I sent was tested on real Panda, including the platform end which actually exists.

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