Re: Switch GPIO direction on Raspberry Pi using ioctl()

[Martin Mersberger <gremlin%portal-to-web.de@localhost>]

Am 04.04.15 um 15:13 schrieb Marc Balmer:


Hi Marc,

[gpio direction vs securelevel]

> Whether that rule should be relaxed can be the topic of a discussion.  I
> could imagine a setting where in runlevel 0 you could specify that
> certain pins remain changeable, even after the secure level had been raised.

Well depending on the external interfaces one connects to a GPIO, it may
be ok to have fixed gpio directions or not
(ie the very famous HC-SR04 is fine since it needs a one pin to trigger
measurement and responses back on a 2nd pin and that's it)

If one wants to use something simple (my personal example is a LDR,R,C
combination to measure very roughly the brightness), you may need to
switch directions of a pin.

My todays workaround is to run a kernel with 'INSECURE' option enabled,
but any alternative which would allow a direction change of certain pins
would be great

regards
 Martin