Re: [RFC PATCH] gpiolib: add gpio get direction support
From: Mathias Nyman
Date: Tue Oct 23 2012 - 07:04:05 EST
On 10/23/2012 01:23 AM, Linus Walleij wrote:
On Mon, Oct 22, 2012 at 3:44 PM, Mathias Nyman
If the .get_direction callback is set, then gpiolib will use it
for showing correct gpio direction in sysfs and debug. If not set
then it will work the old way; e.g. guessing everything is input
until direction is set.
If the driver cannot report the direction setting you *could*
cache the result of all calls to gpio_direction_output()
and gpio_direction_input() somewhere. But I don't know
if it's a good idea.
Anyway, if the callback is only called internally in the GPIOlib
why are you making the function public to the entire
Thought I'd do it the same was as gpio_direction_output() and
gpio_direction_input(), but if there is no need for getting the
direction outside gpiolob then it can be skipped. Main motivation was to
get correct direction values in debug and sysfs after boot.
gpiolib currently uses cached values of gpio_direction_output/input() in
sysfs. If the .get_direction callback exists it is used to refresh the
I'll write a new patch without the public gpio_get_direction().
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/