linux-kernel - Re: [PATCH 5/7] drivers: pinctrl: msm: setup GPIO irqchip hierarchy

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Date:   Thu, 20 Dec 2018 12:03:33 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Lina Iyer <ilina@...eaurora.org>, evgreen@...omium.org,
        marc.zyngier@....com
Cc:     linux-kernel@...r.kernel.org, rplsssn@...eaurora.org,
        linux-arm-msm@...r.kernel.org, thierry.reding@...il.com,
        bjorn.andersson@...aro.org, Lina Iyer <ilina@...eaurora.org>
Subject: Re: [PATCH 5/7] drivers: pinctrl: msm: setup GPIO irqchip hierarchy

Quoting Lina Iyer (2018-12-19 14:11:03)
> To allow GPIOs to wakeup the system from suspend or deep idle, the
> wakeup capable GPIOs are setup in hierarchy with interrupts from the
> wakeup-parent irqchip.
> 
> In older SoC's, the TLMM will handover detection to the parent irqchip
> and in newer SoC's, the parent irqchip may also be active as well as the
> TLMM and therefore the GPIOs need to be masked at TLMM to avoid
> duplicate interrupts. To enable both these configurations to exist,
> allow the parent irqchip to dictate the TLMM irqchip's behavior when
> masking/unmasking the interrupt.
> 
> Signed-off-by: Stephen Boyd <sboyd@...nel.org>

I don't think I gave a signed-off-by, so you need to ask to forge my
sign off here. Please change it to be:

 Signed-off-by: Stephen Boyd <swboyd@...omium.org>

and I'm not sure how much I wrote vs. you wrote anymore so perhaps also
add a

 Co-developed-by: Stephen Boyd <swboyd@...omium.org>

And finally, please just email my chromium.org email for this series
because I apparently messed up the address once and now it's all going
to the wrong inbox. Thanks!

> Signed-off-by: Lina Iyer <ilina@...eaurora.org>

Can you Cc Linus Walleij and Bjorn Andersson on the whole patch series
next time? Would be good to have their review on major pinctrl driver
changes.

> @@ -967,11 +994,86 @@ static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
>         return device_property_read_u16_array(pctrl->dev, "gpios", NULL, 0) > 0;
>  }
>  
> +static int msm_gpio_domain_translate(struct irq_domain *d,
> +                                    struct irq_fwspec *fwspec,
> +                                    unsigned long *hwirq, unsigned int *type)
> +{
> +       if (is_of_node(fwspec->fwnode)) {
> +               if (fwspec->param_count < 2)
> +                       return -EINVAL;
> +               *hwirq = fwspec->param[0];
> +               *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> +               return 0;
> +       }
> +
> +       return -EINVAL;
> +}

Maybe this can be a generic function in gpiolib?

> +
> +static int msm_gpio_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +                                unsigned int nr_irqs, void *arg)
> +{
> +       int ret;
> +       irq_hw_number_t hwirq;
> +       struct gpio_chip *gc = domain->host_data;
> +       struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
> +       struct irq_fwspec *fwspec = arg;
> +       struct qcom_irq_fwspec parent = { };
> +       unsigned int type;
> +
> +       ret = msm_gpio_domain_translate(domain, fwspec, &hwirq, &type);
> +       if (ret)
> +               return ret;
> +
> +       ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
> +                                           &pctrl->irq_chip, gc);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (!domain->parent)
> +               return 0;
> +
> +       parent.fwspec.fwnode      = domain->parent->fwnode;
> +       parent.fwspec.param_count = 2;
> +       parent.fwspec.param[0]    = hwirq;
> +       parent.fwspec.param[1]    = type;
> +
> +       ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &parent);
> +       if (ret)
> +               return ret;
> +
> +       if (parent.mask)
> +               set_bit(hwirq, pctrl->wakeup_masked_irqs);
> +
> +       return 0;
> +}
> +
> +/*
> + * TODO: Get rid of this and push it into gpiochip_to_irq()

Hmm.. yeah we need to do this still. I think we can have a generic two
cell function similar to irq_domain_xlate_twocell() that does the fwspec
creation and uses some of the things that we pass to
gpiochip_irqchip_add(), like the default level type. This existing
function is not good to have, so there's work to do to get rid of this.

I was also thinking that maybe we can make the alloc function above take
a struct gpio_irq_fwspec structure that tells the alloc function what
gpiochip the irq is for. That would mean that we need to change the
gpio_to_irq() function below to be generic and stuff the chip inside the
fwspec wrapper structure:

	struct gpio_irq_fwspec {
		struct irq_fwspec fwspec;
		struct gpio_chip *chip;
		unsigned int offset;
	};

but I seem to recall that was not working for some reason.

> + */
> +static int msm_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
> +{
> +       struct irq_fwspec fwspec;
> +
> +       fwspec.fwnode = of_node_to_fwnode(chip->of_node);
> +       fwspec.param[0] = offset;
> +       fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
> +       fwspec.param_count = 2;
> +
> +       return irq_create_fwspec_mapping(&fwspec);
> +}
> +
> +static const struct irq_domain_ops msm_gpio_domain_ops = {
> +       .translate = msm_gpio_domain_translate,
> +       .alloc     = msm_gpio_domain_alloc,
> +       .free      = irq_domain_free_irqs_top,
> +};
> +