On Thu, Mar 01, 2018 at 03:35:23PM +0800, Baolin Wang wrote:

On 28 February 2018 at 22:44, Arnd Bergmann [off-list ref] wrote:

quoted

On Wed, Feb 28, 2018 at 1:44 PM, Baolin Wang [off-list ref] wrote:

quoted

On some platforms (such as Spreadtrum platform), the GPIO keys can only
be triggered by level type. So this patch introduces one property to
indicate if the GPIO trigger type is level trigger or edge trigger.

Signed-off-by: Baolin Wang <redacted>
---
Changes since v2:
 - Use 'interrupt' property to indicate the irq type.

Changes since v1:
 - Diable the GPIO irq until reversing the GPIO level type.

I've looked at your patch in more detail now, and given it a bit more thought.

I wonder if you could move that logic into your gpiochip/irqchip driver instead.
It seems that what you do in the gpio-keys driver is to emulate edge triggered
behavior on a level triggered irqchip.

If you put the same logic into the gpio driver, you could simply make it
pretend to support an edge trigger on both edges and call into the interrupt
handler whenever the state changes.

That is really a good suggestion, which can avoid duplicate level
reverse logic in different drivers. So this patch can be simplified
just adding one trigger_type to indicate the interrupt type (not
always edge trigger). Thanks for your suggestion.

No, there is no need to add trigger type. The gpio-keys driver expects
trigger with both edges, falling and rising. If your GPIO chip does not
support it natively, you need to emulate edge trigger via level
interrupts by reprogramming trigger from active low to active high and
back on the fly. This should be done in the gpiochip/irqchip driver.
There is no need to change gpio-keys driver.

Thanks.

-- 
Dmitry