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SubjectRe: [patch/rfc 1/4] GPIO implementation framework
Date
On Tuesday 13 November 2007, David Brownell wrote:
> So the point of these is to make it easier for platforms
> (or even just boards) to make sure the GPIO number space
> is densely packed, rather than loosely so?  Paying about
> 2KBytes for that privilege.  (Assuming a 32 bit system
> with 256 GPIOs.)
>
> I could see that being a reasonable tradeoff.  I wouldn't
> have started there myself, but you know how that goes!
>
> Does anyone else have any comments on that issue?

Nobody else seems to have any comments on Eric's series
of patches to add a gpio_desc layer ... whereas, I was
looking at updating one platform, and got annoyed at some
stuff that would have been non-issues with them in place!


Eric, would you feel like rolling an all-in-one patch against
the gpiolib support from 2.6.24-rc3-mm? Including updated
versions of your patches:

- [PATCH 2/5] define gpio_chip.requested_str
(renaming it as "label" to match its usage)
- [PATCH 3/5] use a per GPIO "struct gpio_desc"
(but without that needless list; for debug,
just scan the gpio_desc list for the next
non-null chip)
- [PATCH] move per GPIO "is_out" to "struct gpio_desc"
(i.e. patch 4/5)
- [PATCH 5/5] move per GPIO "requested" to "struct gpio_desc"
(and "label" too)

along with removing the ARCH_GPIOS_PER_CHIP symbol, and
reducing ARCH_NR_GPIOS to a value which will waste less
space by default? (Like maybe 256.)

I think an all-in-one patch will be easier to review
and agree on including (or not).

- Dave
-
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