Hi Simon,
On Tue, Oct 29, 2013 at 8:52 AM, Simon Horman <horms@xxxxxxxxxxxx> wrote:
> Hi Laurent,
>
> In 7e1092b5a264c4 ("gpio-rcar: Add support for IRQ_TYPE_EDGE_BOTH")
> I added a 'has_both_edge_trigger' field to struct gpio_rcar_config.
> Setting this adds support IRQ_TYPE_EDGE_BOTH. The motivation for
> this was to allow use of the gpio-keys driver on the lager board.
>
> I am now looking at enabling gpio-keys via DT for koelsch and lager
> and find myself needing to set has_both_edge_trigger somehow.
> I am wondering if you have any ideas on how best to do this.
>
> So far I have two ideas:
>
> 1. Expose has_both_edge_trigger as a binding.
>
> 2. Set has_both_edge_trigger in the driver if the
> compat string is renesas,gpio-r8a7791 or renesas,gpio-r8a7790
> but not for other supported compat strings (as is currently the case).
I think which to pick depends on the type of feature. In the case of
enabling both edge support for this GPIO driver, I believe going with
2) is the best way forward. The reason for this is that all GPIO
instances within a particular SoC seem to either have or not have
support for dual edges. At least that is the case on r8a7790 and
r8a7791.
There may be other properties in the future like per-GPIO hardware
debounce, and I suspect that those may be more suitable for 1) since
they are only supported on a certain set of GPIO pins. So from my POV
this is a case by case thing.
Cheers,
/ magnus
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