Re: PIXIS gpio controller and gpio flags

On Mon, Jul 21, 2008 at 02:12:20PM -0700, Trent Piepho wrote:

On Mon, 21 Jul 2008, Anton Vorontsov wrote:

quoted

On Sat, Jul 19, 2008 at 02:08:01PM -0700, Trent Piepho wrote:

quoted

It doesn't look like you have any way to unset the active low flag.  What if
I unload the leds-gpio driver (or another gpio user) and then try to use the
gpio with something else?  The active low flag is stuck on!

Why would you want to unset the flags? It is specified in the device
tree, and can't be changed. Specifying different flags for the same GPIO
would be an error (plus, Linux forbids shared gpios, so you simply can't
specify one gpio for several devices).

You can't use the same gpio for two different things at the same time, but you
can load a driver, unload it, and then load another.

Hm.. yeah, this might happen. Now I tend to think that transparent
active-low handling wasn't that good idea after all. So, something like
of_gpio_is_active_low(device_node, gpioidx) should be implemented
instead. This function will parse the gpio's = <> flags. Please speak up
if you have any better ideas though.


Thanks for bringing this up,

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2