Subject: Re: RFC: Platform data for onboard USB assets
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: andy.green@linaro.org
Cc: Arnd Bergmann <arnd@arndb.de>, Greg KH <greg@kroah.com>,
        Grant Likely <grant.likely@secretlab.ca>,
        devicetree-discuss@lists.ozlabs.org,
        Mark Brown <broonie@opensource.wolfsonmicro.com>,
        Nicolas Pitre <nicolas.pitre@linaro.org>,
        Linux USB list <linux-usb@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>
In-Reply-To: <4D82979B.2050003@linaro.org>
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	 <20110317214736.GA29014@kroah.com> <201103172333.01474.arnd@arndb.de>
	 <4D82979B.2050003@linaro.org>
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Date: Sat, 19 Mar 2011 09:37:43 +1100
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On Thu, 2011-03-17 at 23:22 +0000, Andy Green wrote:
> 
> 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. 

Except that vid/pid are the -WRONG- way to do that. Your device is
on-board, the proper way to identify it uniquely is it's topological
location, ie path of HW port numbers.

Cheers,
Ben.


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