GPIOLIB, GPIO_SYS and port-wide accesses

[John Williams]

Hi,

As I see it the gpiolib and sysfs export insists on single bit
accesses even on gpio pins that are located on the same physical
device/port.

A couple of years ago there was mention of port-wide accesses being a
good thing:

http://lkml.indiana.edu/hypermail/linux/kernel/0608.0/0731.html
(towards the bottom)

Did anything ever come of that?

Per-bit access is pretty inflexible if you are driving a 7-segment
display or 8-LED bar display, holding lots of file descriptors open
etc, and lots of syscall overhead.

sysfs syntax like

$ echo "240-247" > export
$ echo 255 > gpio240-247/direction  (8-bit binary mask - output)
$ echo 255 > gpio240-247/value (all ones)

would be reasonably friendly, obviously the underlying gpiolib would
have to have some notion of coupled ports.

Any thoughts?

John
-- 
John Williams,
PetaLogix - Linux Solutions for a Reconfigurable World
w: www.petalogix.com  p: +61-7-30090663  f: +61-7-30090663
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