linux-kernel - Re: [PATCH v2 3/5] drivers: pinctrl: msm: enable PDC interrupt only during suspend

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Message-ID: <20180904174759.GA3622@codeaurora.org>
Date:   Tue, 4 Sep 2018 11:47:59 -0600
From:   Lina Iyer <ilina@...eaurora.org>
To:     Matthias Kaehlcke <mka@...omium.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 3/5] drivers: pinctrl: msm: enable PDC interrupt only
 during suspend

On Mon, Aug 27 2018 at 16:57 -0600, Matthias Kaehlcke wrote:
>Hi Lina,
>
>On Fri, Aug 24, 2018 at 02:01:55PM -0600, Lina Iyer wrote:
>> During suspend the system may power down some of the system rails. As a
>> result, the TLMM hw block may not be operational anymore and wakeup
>> capable GPIOs will not be detected. The PDC however will be operational
>> and the GPIOs that are routed to the PDC as IRQs can wake the system up.
>>
>> To avoid being interrupted twice (for TLMM and once for PDC IRQ) when a
>> GPIO trips, use TLMM for active and switch to PDC for suspend. When
>> entering suspend, disable the TLMM wakeup interrupt and instead enable
>> the PDC IRQ and revert upon resume.
>>
>> Signed-off-by: Lina Iyer <ilina@...eaurora.org>
>> ---
>> Changes in v2:
>> 	- Fix PDC IRQ max port, 126 is the max supported in h/w
>> 	- Use PDC hwirq in bitmap, linux numbers could be large
>> 	- Setup DISABLE_UNLAZY for both TLMM and PDC IRQs
>> ---
>>  drivers/pinctrl/qcom/pinctrl-msm.c | 70 +++++++++++++++++++++++++++++-
>>  drivers/pinctrl/qcom/pinctrl-msm.h |  3 ++
>>  2 files changed, 72 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
>> index b675ea56a4ff..a880cefbd248 100644
>> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
>> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
>> @@ -37,6 +37,7 @@
>>  #include "../pinctrl-utils.h"
>>
>>  #define MAX_NR_GPIO 300
>> +#define MAX_PDC_HWIRQ 126
>>  #define PS_HOLD_OFFSET 0x820
>>
>>  /**
>> @@ -51,6 +52,7 @@
>>   * @enabled_irqs:   Bitmap of currently enabled irqs.
>>   * @dual_edge_irqs: Bitmap of irqs that need sw emulated dual edge
>>   *                  detection.
>> + * @pdc_hwirqs:     Bitmap of wakeup capable irqs.
>>   * @soc;            Reference to soc_data of platform specific data.
>>   * @regs:           Base address for the TLMM register map.
>>   */
>> @@ -68,11 +70,15 @@ struct msm_pinctrl {
>>
>>  	DECLARE_BITMAP(dual_edge_irqs, MAX_NR_GPIO);
>>  	DECLARE_BITMAP(enabled_irqs, MAX_NR_GPIO);
>> +	DECLARE_BITMAP(pdc_hwirqs, MAX_PDC_HWIRQ);
>>
>>  	const struct msm_pinctrl_soc_data *soc;
>>  	void __iomem *regs;
>> +	struct irq_domain *pdc_irq_domain;
>>  };
>>
>> +static bool in_suspend;
>> +
>>  static int msm_get_groups_count(struct pinctrl_dev *pctldev)
>>  {
>>  	struct msm_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
>> @@ -787,8 +793,13 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
>>
>>  	raw_spin_lock_irqsave(&pctrl->lock, flags);
>>
>> -	if (pdc_irqd)
>> +	if (pdc_irqd && !in_suspend) {
>>  		irq_set_irq_wake(pdc_irqd->irq, on);
>> +		if (on)
>> +			set_bit(pdc_irqd->hwirq, pctrl->pdc_hwirqs);
>> +		else
>> +			clear_bit(pdc_irqd->hwirq, pctrl->pdc_hwirqs);
>> +	}
>>
>>  	irq_set_irq_wake(pctrl->irq, on);
>>
>> @@ -919,7 +930,12 @@ static int msm_gpio_pdc_pin_request(struct irq_data *d)
>>  	}
>>
>>  	irq_set_handler_data(d->irq, irq_get_irq_data(irq));
>> +	irq_set_handler_data(irq, d);
>> +	irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY);
>> +	irq_set_status_flags(d->irq, IRQ_DISABLE_UNLAZY);
>>  	disable_irq(irq);
>> +	if (!pctrl->pdc_irq_domain)
>> +		pctrl->pdc_irq_domain = irq_get_irq_data(irq)->domain;
>>
>>  	return 0;
>>  }
>> @@ -1069,6 +1085,58 @@ static void msm_pinctrl_setup_pm_reset(struct msm_pinctrl *pctrl)
>>  		}
>>  }
>>
>> +int __maybe_unused msm_pinctrl_suspend_late(struct device *dev)
>> +{
>> +	struct msm_pinctrl *pctrl = dev_get_drvdata(dev);
>> +	struct irq_data *irqd;
>> +	unsigned int irq;
>> +	int i;
>> +
>> +	in_suspend = true;
>> +	for_each_set_bit(i, pctrl->pdc_hwirqs, MAX_PDC_HWIRQ) {
>> +		irq = irq_find_mapping(pctrl->pdc_irq_domain, i);
>> +		irqd = irq_get_handler_data(irq);
>> +		/*
>> +		 * We don't know if the TLMM will be functional
>> +		 * or not, during the suspend. If its functional,
>> +		 * we do not want duplicate interrupts from PDC.
>> +		 * Hence disable the GPIO IRQ and enable PDC IRQ.
>> +		 */
>> +		if (irqd_is_wakeup_set(irqd)) {
>> +			disable_irq_wake(irqd->irq);
>> +			disable_irq(irqd->irq);
>> +			enable_irq(irq);
>> +		}
>
>Would it make sense to limit this to edge triggered interrupts since
>the interrupt handler does nothing for level triggered ones?
>
Sure.

-- Lina