On Mon, Aug 27 2018 at 18:26 -0600, Bjorn Andersson wrote:
On Mon 27 Aug 09:56 PDT 2018, Lina Iyer wrote:
On Sun, Aug 26 2018 at 08:33 -0600, Linus Walleij wrote:
> On Fri, Aug 17, 2018 at 6:39 PM Lina Iyer <il...@codeaurora.org> wrote:
>
> > QCOM SoC's that have Power Domain Controller (PDC) chip in the always-on
> > domain can wakeup the SoC, when interrupts and GPIOs are routed to the
> > its interrupt controller. Only select GPIOs that are deemed wakeup
> > capable are routed to specific PDC pins. During low power state, the
> > pinmux interrupt controller may be non-functional but the PDC would be.
> > The PDC can detect the wakeup GPIO is triggered and bring the TLMM to an
> > operational state.
> >
> > Interrupts that are level triggered will be detected at the TLMM when
> > the controller becomes operational. Edge interrupts however need to be
> > replayed again.
> >
> > Request the corresponding PDC IRQ, when the GPIO is requested as an IRQ,
> > but keep it disabled. During suspend, we can enable the PDC IRQ instead
> > of the GPIO IRQ, which may or not be detected.
> >
> > Signed-off-by: Lina Iyer <il...@codeaurora.org>
> > ---
> > Changes in v1:
> > - Trigger GPIO in h/w from PDC IRQ handler
> > - Avoid big tables for GPIO-PDC map, pick from DT instead
> > - Use handler_data
>
> Just for the record this is an impressive and much needed patch
> set, no other SoC developer has yet taken on the task of making this
> work so I very much appreciate that Qualcomm show the way.
>
> > +static int msm_gpio_pdc_pin_request(struct irq_data *d)
> > +static int msm_gpio_pdc_pin_release(struct irq_data *d)
> > +static int msm_gpio_irq_reqres(struct irq_data *d)
> > +{
> (...)
> > + if (gpiochip_lock_as_irq(gc, irqd_to_hwirq(d))) {
> (...)
> > +static void msm_gpio_irq_relres(struct irq_data *d)
> > +{
> > + gpiochip_unlock_as_irq(gc, irqd_to_hwirq(d));
> > +}
>
> FYI Hans Verkuil is working on a patch set that moves the
> lock/unlock as IRQ call to the irqchip request() and release()
> functions so we can switch a GPIO irqchip line from IRQ
> mode to say output at runtime without too much trouble.
> (CEC needs this.)
>
Thanks, I will look into Hans's RFCv2. But what would help me would be
to avoid creating the IRQ for the GPIO itself (I have the latent IRQ),
if I could just return that instead in gpio_to_irq(), it might be
easier. I understand ->to_irq() is supposed to be a translate function
only, I can avoid the dance of enabling and diabling the PDC IRQ on
suspend and resume.
I did implement gpio_to_irq() like this in the PMIC gpio/mpp drivers and
we've since concluded that we need to move this to some hierarchical
interrupt controller, because people like Linus expect to be able to say
interrupts = <&gpio_controller 1 IRQ_TYPE_EDGE_RISING>
which is something used all over the place with the TLMM driver today.
Does it have to be &gpio_controller, can it be another interrupt controller?
Say,
interrupts-extended = <&pdc 1 IRQ_TYPE_EDGE_RISING>;
-- Lina
