[PATCH v3] RFC: pinctrl: bcm2835: switch to GPIOLIB_IRQCHIP

[Linus Walleij]

On Mon, Nov 14, 2016 at 6:52 PM, Linus Walleij <linus.walleij at linaro.org> wrote:

> It should be possible to use the GPIOLIB_IRQCHIP helper
> library with the BCM2835 driver since it is a pretty straight
> forward cascaded irqchip.
>
> The only difference from other drivers is that the BCM2835
> has several banks for a single gpiochip, and each bank has
> a separate IRQ line. Instead of creating one gpiochip per
> bank, a single gpiochip covers all banks GPIO lines. This
> makes it necessary to resolve the bank ID in the IRQ
> handler.
>
> The GPIOLIB_IRQCHIP allows several IRQs to be cascaded off
> the same gpiochip by calling gpiochip_set_chained_irqchip()
> repeatedly, but we have been a bit short on examples
> for how this should be handled in practice, so this is intended
> as an example of how this can be achieved.
>
> The old code did not model the chip as a chained interrupt
> handler, but this patch also rectifies that situation.
>
> Cc: Stephen Warren <swarren at wwwdotorg.org>
> Cc: Stefan Wahren <stefan.wahren at i2se.com>
> Cc: Eric Anholt <eric at anholt.net>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> ChangeLog v2->v3:
> - Rebase on top of the two new patches from the vendor tree.
> ChangeLog v1->v2:
> - Forgot to convert the driver to chained IRQ handler. Now fixed.
>
> Rpi folks: I have no clue if this works or not, but would be happy
> if you could test it to see if IRQs fire as expected and provide
> some feedback.

Any testers?

I'm getting tempted to just apply it to get test coverage, at the
cost of having to revert it if it just explodes...

Yours,
Linus Walleij