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.
-hpa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
