pinctrl: qcom: Move clearing pending IRQ to .irq_request_resources callback

When GPIOs that are routed to PDC are used as output they can still latch
the IRQ pending at GIC. As a result the spurious IRQ was handled when the
client driver change the direction to input to starts using it as IRQ.

Currently such erroneous latched IRQ are cleared with .irq_enable callback
however if the driver continue to use GPIO as interrupt and invokes
disable_irq() followed by enable_irq() then everytime during enable_irq()
previously latched interrupt gets cleared.

This can make edge IRQs not seen after enable_irq() if they had arrived
after the driver has invoked disable_irq() and were pending at GIC.

Move clearing erroneous IRQ to .irq_request_resources callback as this is
the place where GPIO direction is changed as input and its locked as IRQ.

While at this add a missing check to invoke msm_gpio_irq_clear_unmask()
from .irq_enable callback only when GPIO is not routed to PDC.

Fixes: e35a6ae0eb3a ("pinctrl/msm: Setup GPIO chip in hierarchy")
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Link: https://lore.kernel.org/r/1604561884-10166-1-git-send-email-mkshah@codeaurora.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index c4bcda9..77a25bd 100644 (file)
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -815,21 +815,14 @@ static void msm_gpio_irq_clear_unmask(struct irq_data *d, bool status_clear)
 
 static void msm_gpio_irq_enable(struct irq_data *d)
 {
-       /*
-        * Clear the interrupt that may be pending before we enable
-        * the line.
-        * This is especially a problem with the GPIOs routed to the
-        * PDC. These GPIOs are direct-connect interrupts to the GIC.
-        * Disabling the interrupt line at the PDC does not prevent
-        * the interrupt from being latched at the GIC. The state at
-        * GIC needs to be cleared before enabling.
-        */
-       if (d->parent_data) {
-               irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, 0);
+       struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+       struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
+
+       if (d->parent_data)
                irq_chip_enable_parent(d);
-       }
 
-       msm_gpio_irq_clear_unmask(d, true);
+       if (!test_bit(d->hwirq, pctrl->skip_wake_irqs))
+               msm_gpio_irq_clear_unmask(d, true);
 }
 
 static void msm_gpio_irq_disable(struct irq_data *d)
@@ -1104,6 +1097,19 @@ static int msm_gpio_irq_reqres(struct irq_data *d)
                ret = -EINVAL;
                goto out;
        }
+
+       /*
+        * Clear the interrupt that may be pending before we enable
+        * the line.
+        * This is especially a problem with the GPIOs routed to the
+        * PDC. These GPIOs are direct-connect interrupts to the GIC.
+        * Disabling the interrupt line at the PDC does not prevent
+        * the interrupt from being latched at the GIC. The state at
+        * GIC needs to be cleared before enabling.
+        */
+       if (d->parent_data && test_bit(d->hwirq, pctrl->skip_wake_irqs))
+               irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, 0);
+
        return 0;
 out:
        module_put(gc->owner);