gpio: tegra: use new gpio_lock_as_irq() API

Whenever an IRQ is claimed or freed, call gpio_lock_as_irq() or
gpio_unlock_as_irq() on the associated GPIO, to prevent that GPIO from
being configured in a manner incompatible with an interrupt.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-tegra.c

@@ -75,6 +75,7 @@ struct tegra_gpio_bank {
 #endif
 };
 
+static struct device *dev;
 static struct irq_domain *irq_domain;
 static void __iomem *regs;
 static u32 tegra_gpio_bank_count;
@@ -205,6 +206,7 @@ static int tegra_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 	int lvl_type;
 	int val;
 	unsigned long flags;
+	int ret;
 
 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_RISING:
@@ -231,6 +233,12 @@ static int tegra_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 		return -EINVAL;
 	}
 
+	ret = gpio_lock_as_irq(&tegra_gpio_chip, gpio);
+	if (ret) {
+		dev_err(dev, "unable to lock Tegra GPIO %d as IRQ\n", gpio);
+		return ret;
+	}
+
 	spin_lock_irqsave(&bank->lvl_lock[port], flags);
 
 	val = tegra_gpio_readl(GPIO_INT_LVL(gpio));
@@ -251,6 +259,13 @@ static int tegra_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 	return 0;
 }
 
+static void tegra_gpio_irq_shutdown(struct irq_data *d)
+{
+	int gpio = d->hwirq;
+
+	gpio_unlock_as_irq(&tegra_gpio_chip, gpio);
+}
+
 static void tegra_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 {
 	struct tegra_gpio_bank *bank;
@@ -368,6 +383,7 @@ static struct irq_chip tegra_gpio_irq_chip = {
 	.irq_mask	= tegra_gpio_irq_mask,
 	.irq_unmask	= tegra_gpio_irq_unmask,
 	.irq_set_type	= tegra_gpio_irq_set_type,
+	.irq_shutdown	= tegra_gpio_irq_shutdown,
 #ifdef CONFIG_PM_SLEEP
 	.irq_set_wake	= tegra_gpio_irq_set_wake,
 #endif
@@ -413,6 +429,8 @@ static int tegra_gpio_probe(struct platform_device *pdev)
 	int i;
 	int j;
 
+	dev = &pdev->dev;
+
 	match = of_match_device(tegra_gpio_of_match, &pdev->dev);
 	if (!match) {
 		dev_err(&pdev->dev, "Error: No device match found\n");