On Tue, Oct 07, 2014 at 03:10:01PM +0200, Geert Uytterhoeven wrote:
On Tue, Oct 7, 2014 at 2:38 PM, Mark Brown broonie@kernel.org wrote:
The fix here is to not allow 0 as a GPIO in the core code (which should've been there already).
Unfortunately it's not there.
And it's not as simple as changing the definition of gpio_is_valid() (crash in gpio_get_value()):
gpiochip_add: GPIOs 0..211 (r8a7740_pfc) failed to register sh-pfc pfc-r8a7740: failed to init GPIO chip, ignoring... sh-pfc pfc-r8a7740: r8a7740_pfc support registered Unable to handle kernel NULL pointer dereference at virtual address 0000004c
Right, obviously it's not going to work if the platform actually uses 0 as a valid GPIO.
Quoting Linus (https://lkml.org/lkml/2014/9/4/464): "Fixing the old global GPIO numberspace API is a waste of time IMO".
Hence I've just sent a patch to initialize the GPIO numbers with -ENOENT.
I do think it's worth renumbering the platforms since it's *relatively* little work per platform compared to completing the gpiod transition.