Re: RFC: gpio attachment for ppbus

[David Brownlee <abs%NetBSD.org@localhost>]

On Tue, 29 Apr 2008, Hans Rosenfeld wrote:

> On Tue, Apr 29, 2008 at 11:47:08AM +0200, Quentin Garnier wrote:
> > > 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.
>
> That would miss the point of reducing the number of syscalls needed to
> perform a large number of gpio operations. But maybe this issue is not
> important enough to justify such a huge extension.

        Putting the interface in a library does not preclude adding
        a syscall or ioctl at a later point to improve performance,
        without needing to change the userland API. Hmm... plists...

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