Re: [PATCH 1/2] cs5535-gpio: add AMD CS5535/CS5536 GPIO driver support

From: Tobias MÃller
Date: Sat Aug 15 2009 - 07:00:31 EST


2009/7/2 David Brownell <david-b@xxxxxxxxxxx>:
> Correct-but-annoying ... and maybe worth changing. ÂThe
> direction *displayed* may not reflect the actual hardware
> until after that GPIO signal is initialized. ÂBoot firmware
> may well have set the direction; Linux shouldn't change it
> without explicit instructions to do so.
OK. If this is a know problem with all GPIO drivers, we can
skip these to two lines to set in pin a defined state.

> So it would be nice to remove the heuristic. ÂThe best
> way would be to add a new method to query gpio direction.
> Then that when it's available, instead of the heuristic.
This can be implemented when the GPIO interface supports it.

The problem with the mask still occurs. I changed to default
mask to 0x0F7FFFFF, so that all pins except the reserved
ones and the power-pin (which needs special handling) are
enabled. Shall we keep it this way (which I prefer) or delete
it entirely?

Sorry, for the late reply, holidays were nice. :)
Tobias
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