linux-kernel - Re: [PATCH 2/3] qcom: spmi-gpio: add support for hierarchical IRQ chip

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Message-ID: <20190105120844.GA2298@basecamp>
Date:   Sat, 5 Jan 2019 07:08:44 -0500
From:   Brian Masney <masneyb@...tation.org>
To:     Stephen Boyd <sboyd@...nel.org>
Cc:     andy.gross@...aro.org, bjorn.andersson@...aro.org,
        linus.walleij@...aro.org, marc.zyngier@....com,
        shawnguo@...nel.org, dianders@...omium.org,
        linux-gpio@...r.kernel.org, nicolas.dechesne@...aro.org,
        niklas.cassel@...aro.org, david.brown@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com, thierry.reding@...il.com,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 2/3] qcom: spmi-gpio: add support for hierarchical IRQ
 chip

On Thu, Jan 03, 2019 at 04:48:33PM -0800, Stephen Boyd wrote:
> I'd think we want the interrupt-cells for the pmic gpio controller to be
> 2 cells (pin and flags) instead of 4 like you have here to match the
> parent interrupt specifier.

I originally went with 4 interrupt cells for spmi-gpio to match the
number of cells on the parent (spmi-arb). From qcom-msm8974.dtsi:

spmi_bus: spmi@...cf000 {
	compatible = "qcom,spmi-pmic-arb";
	interrupt-controller;
	#interrupt-cells = <4>;
	...
};

I agree that we should go with 2 cells for spmi-gpio.

> I also seem to recall that GPIO numbering starts from 1 instead of
> 0, so please keep that in mind.

I'm using the pinctrl numbering, which is zero based.

/ # head /sys/kernel/debug/pinctrl/fc4cf000.spmi\:pm8941@0\:gpios@...0/pins 
registered pins: 36
pin 0 (gpio1) 
pin 1 (gpio2) 
pin 2 (gpio3) 
pin 3 (gpio4) 
pin 4 (gpio5) 
pin 5 (gpio6) 
pin 6 (gpio7) 
pin 7 (gpio8) 
pin 8 (gpio9) 

> > +static int pmic_gpio_irq_activate(struct irq_domain *domain,
> > +                                 struct irq_data *data, bool reserve)
> > +{
> > +       struct pmic_gpio_state *state = domain->host_data;
> 
> How about just storing the gpiochip in the domain->host_data?
> 
> > +
> > +       return gpiochip_lock_as_irq(&state->chip, data->hwirq);
> > +}
> > +
> > +static void pmic_gpio_irq_deactivate(struct irq_domain *domain,
> > +                                    struct irq_data *data)
> > +{
> > +       struct pmic_gpio_state *state = domain->host_data;
> > +
> > +       gpiochip_unlock_as_irq(&state->chip, data->hwirq);
> > +}
> > +
> 
> Then these could be generic gpiolib APIs?

I tried this:

static const struct irq_domain_ops pmic_gpio_domain_ops = {
        .activate = gpiochip_lock_as_irq,
        .alloc = pmic_gpio_domain_alloc,
        .deactivate = gpiochip_unlock_as_irq,
        .free = irq_domain_free_irqs_common,
        .translate = pmic_gpio_domain_translate,
};

But get an incompatible pointer types compiler error.

drivers/pinctrl/qcom/pinctrl-spmi-gpio.c:1003:14: error: initialization of
‘int (*)(struct irq_domain *, struct irq_data *, bool)’ {aka ‘int
(*)(struct irq_domain *, struct irq_data *, _Bool)’} from incompatible
pointer type ‘int (*)(struct gpio_chip *, unsigned int)’
[-Werror=incompatible-pointer-types]


> > +static int pmic_gpio_domain_alloc(struct irq_domain *domain, unsigned int virq,
> > +                                 unsigned int nr_irqs, void *data)
> > +{
> > +       struct pmic_gpio_state *state = domain->host_data;
> > +       struct irq_fwspec *fwspec = data;
> > +       struct irq_fwspec parent_fwspec;
> > +       irq_hw_number_t hwirq;
> > +       unsigned int type;
> > +       int ret, i;
> > +
> > +       ret = pmic_gpio_domain_translate(domain, fwspec, &hwirq, &type);
> > +       if (ret)
> > +               return ret;
> > +
> > +       for (i = 0; i < nr_irqs; i++)
> > +               irq_domain_set_info(domain, virq + i, hwirq + i,
> > +                                   &pmic_gpio_irq_chip, state,
> > +                                   handle_level_irq, NULL, NULL);
> 
> Does almost nobody pass a name for that last parameter?

I see 26 callers to irq_domain_set_info() outside this patch set and
only 3 of them actually set a name. I'm open to suggestions for what to
put here.

Brian