Re: [PATCH v2 1/5] drivers: pinctrl: qcom: add wakeup capability to GPIO

[Lina Iyer]

On Mon, Aug 20 2018 at 00:05 -0600, Bjorn Andersson wrote:
> On Fri 17 Aug 09:38 PDT 2018, Lina Iyer wrote:
>
> Thanks Lina, I think this looks like a very reasonable approach!
>
> > 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.
>
> Afaict we can model a driver for the MPM hardware - for previous
> platforms - after your PDC driver and all of this logic will be reused.
>
> As such I think it would be better to use the word "wake" instead of
> "pdc" in the implementation. I don't see a problem with the commit
> message being specific and talking about the PDC though, so keep that.
>
> > Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> > ---
> > 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
> > ---
> >  drivers/pinctrl/qcom/pinctrl-msm.c | 97 ++++++++++++++++++++++++++++++
> >  1 file changed, 97 insertions(+)
> >
> > diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> > index 0e22f52b2a19..03ef1d29d078 100644
> > --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> > +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> > @@ -687,11 +687,15 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)
> >  	const struct msm_pingroup *g;
> >  	unsigned long flags;
> >  	u32 val;
> > +	struct irq_data *pdc_irqd = irq_get_handler_data(d->irq);
> >
> >  	g = &pctrl->soc->groups[d->hwirq];
> >
> >  	raw_spin_lock_irqsave(&pctrl->lock, flags);
> >
> > +	if (pdc_irqd)
> > +		irq_set_irq_type(pdc_irqd->irq, type);
> > +
> >  	/*
> >  	 * For hw without possibility of detecting both edges
> >  	 */
> > @@ -779,9 +783,13 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
> >  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> >  	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
> >  	unsigned long flags;
> > +	struct irq_data *pdc_irqd = irq_get_handler_data(d->irq);
> >
> >  	raw_spin_lock_irqsave(&pctrl->lock, flags);
> >
> > +	if (pdc_irqd)
> > +		irq_set_irq_wake(pdc_irqd->irq, on);
> > +
> >  	irq_set_irq_wake(pctrl->irq, on);
>
> Given that the TLMM summary logic isn't powered during a collapse, is
> there really a point in toggling the wake of the summary irq? (I wrote
> this, not sure it is correct)
>
> Also, we're not modifying any tlmm state here, so we shouldn't need that
> spinlock.
Okay.
> >  	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
> > @@ -863,6 +871,93 @@ static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
> >  	return device_property_read_u16_array(pctrl->dev, "gpios", NULL, 0) > 0;
> >  }
> >
> > +static irqreturn_t wake_irq_gpio_handler(int irq, void *data)
> > +{
> > +	struct irq_data *irqd = data;
> > +	struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
> > +	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
> > +	const struct msm_pingroup *g;
> > +	unsigned long flags;
> > +	u32 val;
> > +
> > +	if (!irqd_is_level_type(irqd)) {
>
> This deserves a comment in the code as well.
Will add.

> > +		g = &pctrl->soc->groups[irqd->hwirq];
> > +		raw_spin_lock_irqsave(&pctrl->lock, flags);
> > +		val = BIT(g->intr_status_bit);
> > +		writel(val, pctrl->regs + g->intr_status_reg);
> > +		raw_spin_unlock_irqrestore(&pctrl->lock, flags);
> > +	}
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int msm_gpio_pdc_pin_request(struct irq_data *d)
> > +{
> > +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
> > +	struct platform_device *pdev = to_platform_device(pctrl->dev);
> > +	unsigned irq;
> > +	unsigned long trigger;
> > +	const char *pin_name;
> > +	int ret;
> > +
> > +	pin_name = kasprintf(GFP_KERNEL, "gpio%lu", d->hwirq);
>
> pin_name needs to be released in msm_gpio_pdc_pin_release() as well.
>
> > +	if (!pin_name)
> > +		return -ENOMEM;
> > +
> > +	irq = platform_get_irq_byname(pdev, pin_name);
> > +	if (irq < 0) {
> > +		kfree(pin_name);
> > +		return 0;
> > +	}
> > +
> > +	trigger = irqd_get_trigger_type(d) | IRQF_ONESHOT | IRQF_NO_SUSPEND;
> > +	ret = request_irq(irq, wake_irq_gpio_handler, trigger, pin_name, d);
> > +	if (ret) {
> > +		pr_warn("GPIO-%lu could not be set up as wakeup", d->hwirq);
> > +		kfree(pin_name);
> > +		return ret;
> > +	}
> > +
> > +	irq_set_handler_data(d->irq, irq_get_irq_data(irq));
> > +	disable_irq(irq);
> > +
> > +	return 0;
> > +}
> > +
> > +static int msm_gpio_pdc_pin_release(struct irq_data *d)
> > +{
> > +	struct irq_data *pdc_irqd = irq_get_handler_data(d->irq);
> > +
> > +	if (pdc_irqd) {
> > +		irq_set_handler_data(d->irq, NULL);
> > +		free_irq(pdc_irqd->irq, d);
>
> free_irq() returns what was "pin_name" in msm_gpio_pdc_pin_request(), so
> you should be able to free that.
Just realized the return value. Will fix.

Thanks,
Lina