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SubjectRe: [PATCH v3 1/5] drivers: pinctrl: qcom: add wakeup capability to GPIO
On Tue, Oct 02 2018 at 11:06 -0600, Lina Iyer wrote:
>Marc,
>
>I am exploring an option where we don't do this enable/disable every
>suspend/resume and in that process, I was able to just use the PDC
>interrupt instead of the TLMM for triggering the GPIO. The PDC interrupt
>(which takes over for the GPIO) has an handler like this -
>
>On Tue, Sep 04 2018 at 15:18 -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 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.
>>
>>Signed-off-by: Lina Iyer <ilina@codeaurora.org>
>>---
>>Changes in v3:
>> - free action->name
>>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 | 98 ++++++++++++++++++++++++++++++
>>1 file changed, 98 insertions(+)
>>
>>diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
>>index 0e22f52b2a19..6527a0a9edd1 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);
>>+
>I skip over the TLMM configuration for the GPIO interrupt and just set
>the IRQ handler for the GPIO interrupt here..
>
>> /*
>> * 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 +871,94 @@ 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;
>>+}
>>+
>
>Then ...
>
>static irqreturn_t wake_irq_gpio_handler(int irq, void *data)
>{
> struct irq_data *irqd = data;
> struct irq_desc *desc = irq_to_desc(irqd->irq);
>
> desc->handle_irq(desc);
>
> return IRQ_HANDLED;
>}
>
>I am following check_irq_resend() but I need to call the handler for
>both level and edge interrupts. Firstly, is it okay to call the
>handler_irq() directly?
>
>My other question is check_irq_resend() indicates that it should be
>called with desc->lock held. Since we are invoking the handler directly
>and not modifying any core state of the irq_desc, is it safe here? (Also
>the locking API are not exposed, I am sure there must be a reason for it).
>
>Thoughts?
>
Would it help if I submit a RFC patch based on this idea?

>Thanks,
>Lina
>
>>+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;
>>+ }
>>+
>>+ 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);
>>+ 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);
>>+ const void *name;
>>+
>>+ if (pdc_irqd) {
>>+ irq_set_handler_data(d->irq, NULL);
>>+ name = free_irq(pdc_irqd->irq, d);
>>+ kfree(name);
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+static int msm_gpio_irq_reqres(struct irq_data *d)
>>+{
>>+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
>>+
>>+ if (gpiochip_lock_as_irq(gc, irqd_to_hwirq(d))) {
>>+ dev_err(gc->parent, "unable to lock HW IRQ %lu for IRQ\n",
>>+ irqd_to_hwirq(d));
>>+ return -EINVAL;
>>+ }
>>+
>>+ return msm_gpio_pdc_pin_request(d);
>>+}
>>+
>>+static void msm_gpio_irq_relres(struct irq_data *d)
>>+{
>>+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
>>+
>>+ msm_gpio_pdc_pin_release(d);
>>+ gpiochip_unlock_as_irq(gc, irqd_to_hwirq(d));
>>+}
>>+
>>static int msm_gpio_init(struct msm_pinctrl *pctrl)
>>{
>> struct gpio_chip *chip;
>>@@ -887,6 +983,8 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
>> pctrl->irq_chip.irq_ack = msm_gpio_irq_ack;
>> pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type;
>> pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake;
>>+ pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
>>+ pctrl->irq_chip.irq_release_resources = msm_gpio_irq_relres;
>>
>> ret = gpiochip_add_data(&pctrl->chip, pctrl);
>> if (ret) {
>>--
>>The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>>a Linux Foundation Collaborative Project
>>

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