Re: [PATCH v2 0/8] qcom: support wakeup capable GPIOs

[Lina Iyer]

On Mon, Jan 28 2019 at 07:19 -0700, Linus Walleij wrote:
> On Thu, Jan 24, 2019 at 9:22 PM Lina Iyer <ilina@xxxxxxxxxxxxxx> wrote:
>
> > This is a bug fix submission of the v1 posted here [1]. The discussion on how
> > to represent the wakeup-parent interrupt controller is on-going [2] here. The
> > reiew comments in [1], from Doug and Stephen are addressed in this patch.
> >
> > The series attempts to add GPIO chip in hierarchy with PDC interrupt controller
> > that can detect and wakeup the GPIOs routed to it, when the system is
> > suspend/deep sleep mode.
>
> I kind of start to get the hang of this now. This is starting to
> look finished. Some words on the hierarchical GPIO IRQs:
>
> I have started to look into hierarchical GPIO+irqchip since
> the usage of such is spreading.
>
> I have been on to Thierry patches trying to make him implement
> more generic helpers in the gpiolib irqchip library functions.
>
> In short I see the following:
>
> - Hierarchical gpiochips all have .alloc() and .translate() functions
>  that look more or less the same.
Yes.

> - They all fall down to remapping either tuples or entire ranges
>  of IRQs from parent to child with a linear look-up table on
>  allocation.
I would think this would be the generic case, unless its QCOM, where we
would want to push the tuples up hierarchy :(

> So my idea would be to add support for this into the gpiolib
> hierarchical irqchip helper: by supplying a parent irqdomain
> and a list of translation tuples, we should be able to handle
> pretty much any hierarchical GPIO irqdomain (famous last
> words).
We would read the tuples from DT? Also please consider Rob's idea of
specifying hierarchy from [2].

> Right now I am converting the IXP4xx platform to hierarchical
> IRQ from the ground up (it is not even using device tree
> so it is a bit of a challenge) but it seems to be working.
>
> So I will try to post this in some hopefully working form, and
> on top of those changes or before them introduce some
> helpers in the core for hierarchical irqs. Or I fail.
Thanks, please copy me on the thread. I would not want to miss this.

> Anyways, I do not think my ambitions for refactoring the
> helpers can stand in the way of support for these use cases
> and new hardware, so maybe we need to merge a few
> more hierarchical drivers just bypassing the gpiolib
> helpers. I don't want to block development, and I suspect
> Thierry might be getting annoyed at me at this point, so
> we should maybe just pile up a few more hierarchical
> chips so I can refactor them later.
>
> What do you think?
I attempted refactoring the .alloc and .translate and for a generic case
and it seemed like it would fit the bill very well. Will await your
patches.

Thanks,
Lina