gpio: 104-idio-16: Clear pending interrupt in IRQ handler

The ACCES 104-IDIO-16 uses a single interrupt to indicate a possible
change-of-state in any of the digital input lines. As such, only a
single write to the device's "Clear Interrupt" register is necessary to
acknowledge the IRQ for all respective GPIO.

This patch moves the "Clear Interrupt" register write operation from the
irq_ack callback to the IRQ handler function, wherefore each interrupt
may be cleared respectively by executing a single outb call at the end
of the idio_16_irq_handler function, rather than multiple redundant outb
calls as a result of the generic_handle_irq call for each masked GPIO.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-104-idio-16.c b/drivers/gpio/gpio-104-idio-16.c
index efe3ff7d574e3b9b141c5fea0ae2725681c965eb..91c8b5b17f642efec2888a0201371fc885daef9c 100644 (file)
--- a/drivers/gpio/gpio-104-idio-16.c
+++ b/drivers/gpio/gpio-104-idio-16.c
@@ -117,15 +117,6 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 
 static void idio_16_irq_ack(struct irq_data *data)
 {
-       struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
-       struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip);
-       unsigned long flags;
-
-       spin_lock_irqsave(&idio16gpio->lock, flags);
-
-       outb(0, idio16gpio->base + 1);
-
-       spin_unlock_irqrestore(&idio16gpio->lock, flags);
 }
 
 static void idio_16_irq_mask(struct irq_data *data)
@@ -159,7 +150,6 @@ static void idio_16_irq_unmask(struct irq_data *data)
        if (!prev_irq_mask) {
                spin_lock_irqsave(&idio16gpio->lock, flags);
 
-               outb(0, idio16gpio->base + 1);
                inb(idio16gpio->base + 2);
 
                spin_unlock_irqrestore(&idio16gpio->lock, flags);
@@ -193,6 +183,12 @@ static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
        for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
                generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio));
 
+       spin_lock(&idio16gpio->lock);
+
+       outb(0, idio16gpio->base + 1);
+
+       spin_unlock(&idio16gpio->lock);
+
        return IRQ_HANDLED;
 }
 
@@ -244,6 +240,7 @@ static int __init idio_16_probe(struct platform_device *pdev)
 
        /* Disable IRQ by default */
        outb(0, base + 2);
+       outb(0, base + 1);
 
        err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
                handle_edge_irq, IRQ_TYPE_NONE);