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

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Message-ID: <20180827223502.GV160295@google.com>
Date:   Mon, 27 Aug 2018 15:35:02 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Lina Iyer <ilina@...eaurora.org>
Cc:     marc.zyngier@....com, bjorn.andersson@...aro.org, sboyd@...nel.org,
        evgreen@...omium.org, linus.walleij@...aro.org,
        rplsssn@...eaurora.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, rnayak@...eaurora.org,
        devicetree@...r.kernel.org, andy.gross@...aro.org,
        dianders@...omium.org
Subject: Re: [PATCH v2 1/5] drivers: pinctrl: qcom: add wakeup capability to
 GPIO

Hi Lina,

On Fri, Aug 24, 2018 at 02:01:53PM -0600, Lina Iyer 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

wording nit: "are routed to the|its interrupt controller"

> 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 <ilina@...eaurora.org>
> ---
> Changes in v2:
> 	- Remove IRQF_NO_SUSPEND and IRQF_ONE_SHOT from PDC IRQ
> 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 | 96 ++++++++++++++++++++++++++++++
>  1 file changed, 96 insertions(+)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index 0e22f52b2a19..b675ea56a4ff 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);
>  
>  	raw_spin_unlock_irqrestore(&pctrl->lock, flags);
> @@ -863,6 +871,92 @@ 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)) {
> +		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);
> +	const char *pin_name;
> +	int irq;
> +	int ret;
> +
> +	pin_name = kasprintf(GFP_KERNEL, "gpio%lu", d->hwirq);
> +	if (!pin_name)
> +		return -ENOMEM;
> +
> +	irq = platform_get_irq_byname(pdev, pin_name);
> +	if (irq < 0) {
> +		kfree(pin_name);
> +		return 0;

Do I understand correctly that this is the case where the pin isn't
routed to the PDC?

> +	}
> +
> +	ret = request_irq(irq, wake_irq_gpio_handler, irqd_get_trigger_type(d),
> +			  pin_name, d);
> +	if (ret) {
> +		pr_warn("GPIO-%lu could not be set up as wakeup", d->hwirq);

'\n' is missing

> +		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);

You need to free 'pin_name' allocated in msm_gpio_pdc_pin_request().
IIUC it should be available in irq_desc->action->name.

Cheers

Matthias