Re: [RFD] voltage/current regulator consumer interface

[Mark Brown <broonie@sirena.org.uk>]

On Mon, Apr 27, 2009 at 09:47:32AM -0400, James Kosin wrote:
> Mark Brown wrote:

> > This all started because this approach was nacked for serial drivers.
> > In any case, I'm not sure that'll scale - it may not be desirable or
> > reasonable to do something like that for all devices.  For example, the
> > devices may be connected via a technology that's not suitable (I've
> > worked on systems which used ethernet here).

> Ethernet can be treated as a serial interface as well down to the
> simplest level.  I'm leaving out a lot is making this assumption; but,
> it is true to a fault.

The big difference with ethernet is that it's multi-drop - you can't
turn on the power based on the ethernet interface being in use since
there can be more than one device connected.

> The same applies to disk devices, now we have IDE/SATA/etc. the disk
> device itself doesn't depend on the interface physically, the kernel
> treats all these as suitable interfaces for disk/CDROM/tape devices and
> the world is not turned on its ear just because there is a different
> physical interface.

You're suggesting modifying the link layer to do different things based
on which device is connnected to it; in any case the issue here is that
this class of hardware has no in-kernel driver to provide an abstaction
- it's all done by a user space daemon or similar.