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Re: RFC: gpio attachment for ppbus

On Tue, Apr 29, 2008 at 10:46:29AM +0200, Hans Rosenfeld wrote:
> On Mon, Apr 28, 2008 at 05:59:24PM -0400, der Mouse wrote:
> > One thing I would suggest is that you document which order the data
> > pins and the control pins are written in, when changing both.  (Or does
> > the scaffolding allow userland to control that order?  I don't know
> > gpiobus.)
> The current gpio API does not allow changing more than one pin at a
> time, so you are forced to implement the order yourself. There is also
> no distinction between data pins, status pins and control pins, they are
> all just gpio pins. 
> For some future extension of the gpio driver, I thought about adding an
> ioctl() to specify a sequence of operations to perform, complete with
> timing information. The actual operations would still be carried out
> sequentially by the gpio driver, but you wouldn't need an ioctl() for
> every read or write of a pin. But this still needs some more thought.

I think that belongs to a userspace lib, anyway.

Quentin Garnier - -
"See the look on my face from staying too long in one place
[...] every time the morning breaks I know I'm closer to falling"
KT Tunstall, Saving My Face, Drastic Fantastic, 2007.

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