Messages in this thread | | | Date | Sat, 11 Nov 2006 17:27:04 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [patch/rfc 2.6.19-rc5] arch-neutral GPIO calls |
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David Brownell wrote: > > - Only intended for use with "real" GPIOs that work from IRQ context; > e.g. pins on a SOC that are controlled by chip register access. > > - Doesn't handle I2C or SPI based GPIOs. I think we actually need > a different API for those "message based" GPIOs, where synchronous > get/set requires sleeping (and is thus unusable from IRQ context). > That API could be used for "real" GPIOs; the converse is not true. > > - No IORESOURCE_GPIO resource type (could be added though). > > - Can be trivially implemented today, on many systems (see partial > list above) ... no "provider" or gpiochip API necessary. > > - Provided in the form of a working patch, with sample implementation; > known to be viable on multiple architectures and platforms. > > - Includes Documentation/gpio.txt > > Comments? >
If this is done, I think it's essential that a "high-level" API (one that supports message-based GPIO) is provided at the same time. The "high-level" API should be able to address the GPIOs addressed by the low-level API. What we do *not* want is a bunch of stuff using the low-level API when the high-level API would work.
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