gpio: lock adnp IRQs when enabling them

This uses the new API for tagging GPIO lines as in use by
IRQs. This enforces a few semantic checks on how the underlying
GPIO line is used.

Only compile tested on the lpc32xx.

ChangeLog v2->v3:
- Switch to using the startup()/shutdown() callbacks again.
  Still satisfy the mask/unmask semantics.
ChangeLog v1->v2:
- Use the .enable() callback from the irq_chip
- Call .unmask() from the .enable() callback to satisfy semantics.

Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-adnp.c

@@ -408,6 +408,27 @@ static void adnp_irq_bus_unlock(struct irq_data *data)
 	mutex_unlock(&adnp->irq_lock);
 }
 
+static unsigned int adnp_irq_startup(struct irq_data *data)
+{
+	struct adnp *adnp = irq_data_get_irq_chip_data(data);
+
+	if (gpio_lock_as_irq(&adnp->gpio, data->hwirq))
+		dev_err(adnp->gpio.dev,
+			"unable to lock HW IRQ %lu for IRQ\n",
+			data->hwirq);
+	/* Satisfy the .enable semantics by unmasking the line */
+	adnp_irq_unmask(data);
+	return 0;
+}
+
+static void adnp_irq_shutdown(struct irq_data *data)
+{
+	struct adnp *adnp = irq_data_get_irq_chip_data(data);
+
+	adnp_irq_mask(data);
+	gpio_unlock_as_irq(&adnp->gpio, data->hwirq);
+}
+
 static struct irq_chip adnp_irq_chip = {
 	.name = "gpio-adnp",
 	.irq_mask = adnp_irq_mask,
@@ -415,6 +436,8 @@ static struct irq_chip adnp_irq_chip = {
 	.irq_set_type = adnp_irq_set_type,
 	.irq_bus_lock = adnp_irq_bus_lock,
 	.irq_bus_sync_unlock = adnp_irq_bus_unlock,
+	.irq_startup = adnp_irq_startup,
+	.irq_shutdown = adnp_irq_shutdown,
 };
 
 static int adnp_irq_map(struct irq_domain *domain, unsigned int irq,