Thread (1 message) 1 message, 1 author, 2013-08-12

Re: Non-enumerable devices on USB and other enumerable buses

From: Mark Brown <broonie@kernel.org>
Date: 2013-08-12 20:38:45
Also in: lkml

On Mon, Aug 12, 2013 at 12:08:17PM -0600, Stephen Warren wrote:
In a similar way, I wonder if the USB case can be considered the same
way? This seems less like a good fit since I don't expect the resources
are always so similar there, and also there's the case of the bus being
potentially behind a few levels of USB hub.
That won't work for the hub on Arndale in a system where it's fully
wired up - it's got an I2C interface for control and the idea is that
you bring it out of reset, write the configuration out via I2C and then
you can complete startup using a GPIO or another I2C command.
And of course it all gets a little more messy when you get
board-specific logic that needs setup, rather than something more common
across multiple devices.
I think we could probably cover many cases by putting common things onto
the bus but we still need to confront the cases where the device driver
really does need to get involved in what's going on.  Things like the
SDIO WiFi cards seem very interchangable as you say and would probably
benefit a lot but there's other applications that are less regular.

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