Re: [PATCH v4 07/10] drivers: pinctrl: msm: setup GPIO irqchip hierarchy

[Lina Iyer]

On Thu, Mar 21 2019 at 15:54 -0600, Stephen Boyd wrote:
> Quoting Marc Zyngier (2019-03-16 04:39:48)
> > On Fri, 15 Mar 2019 09:28:31 -0700
> > Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> >
> > > Quoting Lina Iyer (2019-03-13 14:18:41)
> > > > @@ -994,6 +1092,22 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
> > > >         pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
> > > >         pctrl->irq_chip.irq_release_resources = msm_gpio_irq_relres;
> > > >
> > > > +       chip->irq.chip = &pctrl->irq_chip;
> > > > +       chip->irq.domain_ops = &msm_gpio_domain_ops;
> > > > +       chip->irq.handler = handle_edge_irq;
> > > > +       chip->irq.default_type = IRQ_TYPE_EDGE_RISING;
> > >
> > > This also changed from v3. It used to be IRQ_TYPE_NONE. Specifying this
> > > here seems to cause gpiolib to print a WARN.
> > >
> > >
> > >         /*
> > >          * Specifying a default trigger is a terrible idea if DT or ACPI is
> > >          * used to configure the interrupts, as you may end up with
> > >          * conflicting triggers. Tell the user, and reset to NONE.
> > >          */
> > >         if (WARN(np && type != IRQ_TYPE_NONE,
> > >                  "%s: Ignoring %u default trigger\n", np->full_name, type))
> > >                 type = IRQ_TYPE_NONE;
> > >
> > >
> > > So I guess this change should be dropped. Or at the least, it should be
> > > split out to it's own patch and the motivations can be discussed in the
> > > commit text.
> >
> > It is something I requested (although I expected this to be a
> > different patch, and even a clarification would have been OK).
> >
> > One way or another, the default trigger must match the flow handler. If
> > we set it up with IRQ_TYPE_NONE, what does it mean? The fact that
> > IRQ_TYPE_NONE acts as a wildcard doesn't mean the handle_edge_irq flow
> > handler is a good match for all interrupt types (it is rarely OK for
> > level interrupts).
>
> I think this is a question for Thierry or Linus. I'm not sure why this
> check was put in place in the code. I tried to dig into it really quick
> but I didn't find anything obvious and then I gave up.
>
> Maybe with hierarchical irqdomains we can drop this check? I don't think
> the gpiolib core ever uses this 'default_type' or 'handler' for anything
> once we replace the irqdomain that's used for a particular gpiochip with
> a custom irqdomain. The only user I see, gpiochip_irq_map(), won't ever
> be called so it really ends up being a thing that the driver specific
> irqdomains should check for and reject when parsing the DT and it sees
> IRQ_TYPE_NONE come out.
>
> ------8<-------
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 144af0733581..fe2f7888c473 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1922,7 +1922,7 @@ static int gpiochip_add_irqchip(struct gpio_chip *gpiochip,
> 	 * used to configure the interrupts, as you may end up with
> 	 * conflicting triggers. Tell the user, and reset to NONE.
> 	 */
> -	if (WARN(np && type != IRQ_TYPE_NONE,
> +	if (WARN(!gpiochip->irq.domain_ops && np && type != IRQ_TYPE_NONE,
> 		 "%s: Ignoring %u default trigger\n", np->full_name, type))
> 		type = IRQ_TYPE_NONE;
Linus,

Any thoughts on this?

-- Lina