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Subject[PATCH v2 1/4] gpio: gpiolib: Allow GPIO IRQs to lazy disable
Date
With 'commit 461c1a7d4733 ("gpiolib: override irq_enable/disable")' gpiolib
overrides irqchip's irq_enable and irq_disable callbacks. If irq_disable
callback is implemented then genirq takes unlazy path to disable irq.

Underlying irqchip may not want to implement irq_disable callback to lazy
disable irq when client drivers invokes disable_irq(). By overriding
irq_disable callback, gpiolib ends up always unlazy disabling IRQ.

Allow gpiolib to lazy disable IRQs by overriding irq_disable callback only
if irqchip implemented irq_disable. In cases where irq_disable is not
implemented irq_mask is overridden. Similarly override irq_enable callback
only if irqchip implemented irq_enable otherwise irq_unmask is overridden.

Fixes: 461c1a7d47 (gpiolib: override irq_enable/disable)
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
---
drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++----------------
include/linux/gpio/driver.h | 13 +++++++++++
2 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index eaa0e20..3810cd0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2465,32 +2465,37 @@ static void gpiochip_irq_relres(struct irq_data *d)
gpiochip_relres_irq(gc, d->hwirq);
}

+static void gpiochip_irq_mask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+ if (gc->irq.irq_mask)
+ gc->irq.irq_mask(d);
+ gpiochip_disable_irq(gc, d->hwirq);
+}
+
+static void gpiochip_irq_unmask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+
+ gpiochip_enable_irq(gc, d->hwirq);
+ if (gc->irq.irq_unmask)
+ gc->irq.irq_unmask(d);
+}
+
static void gpiochip_irq_enable(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

gpiochip_enable_irq(gc, d->hwirq);
- if (gc->irq.irq_enable)
- gc->irq.irq_enable(d);
- else
- gc->irq.chip->irq_unmask(d);
+ gc->irq.irq_enable(d);
}

static void gpiochip_irq_disable(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

- /*
- * Since we override .irq_disable() we need to mimic the
- * behaviour of __irq_disable() in irq/chip.c.
- * First call .irq_disable() if it exists, else mimic the
- * behaviour of mask_irq() which calls .irq_mask() if
- * it exists.
- */
- if (gc->irq.irq_disable)
- gc->irq.irq_disable(d);
- else if (gc->irq.chip->irq_mask)
- gc->irq.chip->irq_mask(d);
+ gc->irq.irq_disable(d);
gpiochip_disable_irq(gc, d->hwirq);
}

@@ -2515,10 +2520,22 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc)
"detected irqchip that is shared with multiple gpiochips: please fix the driver.\n");
return;
}
- gc->irq.irq_enable = irqchip->irq_enable;
- gc->irq.irq_disable = irqchip->irq_disable;
- irqchip->irq_enable = gpiochip_irq_enable;
- irqchip->irq_disable = gpiochip_irq_disable;
+
+ if (irqchip->irq_disable) {
+ gc->irq.irq_disable = irqchip->irq_disable;
+ irqchip->irq_disable = gpiochip_irq_disable;
+ } else {
+ gc->irq.irq_mask = irqchip->irq_mask;
+ irqchip->irq_mask = gpiochip_irq_mask;
+ }
+
+ if (irqchip->irq_enable) {
+ gc->irq.irq_enable = irqchip->irq_enable;
+ irqchip->irq_enable = gpiochip_irq_enable;
+ } else {
+ gc->irq.irq_unmask = irqchip->irq_unmask;
+ irqchip->irq_unmask = gpiochip_irq_unmask;
+ }
}

/**
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 8c41ae4..c8bcaf3 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -253,6 +253,19 @@ struct gpio_irq_chip {
* Store old irq_chip irq_disable callback
*/
void (*irq_disable)(struct irq_data *data);
+ /**
+ * @irq_unmask:
+ *
+ * Store old irq_chip irq_unmask callback
+ */
+ void (*irq_unmask)(struct irq_data *data);
+
+ /**
+ * @irq_mask:
+ *
+ * Store old irq_chip irq_mask callback
+ */
+ void (*irq_mask)(struct irq_data *data);
};

/**
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
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