gpio: Provide the tc3589x GPIO expander driver with an IRQ domain

In preparation for Device Tree enablement all IRQ controllers
should control their own IRQ domain. This patch provides just
that for the tc3589x GPIO expander.

CC: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-tc3589x.c

@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/gpio.h>
 #include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/tc3589x.h>
 
@@ -29,6 +30,7 @@ struct tc3589x_gpio {
 	struct tc3589x *tc3589x;
 	struct device *dev;
 	struct mutex irq_lock;
+	struct irq_domain *domain;
 
 	int irq_base;
 
@@ -92,11 +94,28 @@ static int tc3589x_gpio_direction_input(struct gpio_chip *chip,
 	return tc3589x_set_bits(tc3589x, reg, 1 << pos, 0);
 }
 
+/**
+ * tc3589x_gpio_irq_get_virq(): Map an interrupt on a chip to a virtual IRQ
+ *
+ * @tc3589x_gpio: tc3589x_gpio_irq controller to operate on.
+ * @irq: index of the interrupt requested in the chip IRQs
+ *
+ * Useful for drivers to request their own IRQs.
+ */
+static int tc3589x_gpio_irq_get_virq(struct tc3589x_gpio *tc3589x_gpio,
+				     int irq)
+{
+	if (!tc3589x_gpio)
+		return -EINVAL;
+
+	return irq_create_mapping(tc3589x_gpio->domain, irq);
+}
+
 static int tc3589x_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 {
 	struct tc3589x_gpio *tc3589x_gpio = to_tc3589x_gpio(chip);
 
-	return tc3589x_gpio->irq_base + offset;
+	return tc3589x_gpio_irq_get_virq(tc3589x_gpio, offset);
 }
 
 static struct gpio_chip template_chip = {
@@ -113,7 +132,7 @@ static struct gpio_chip template_chip = {
 static int tc3589x_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 {
 	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - tc3589x_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -175,7 +194,7 @@ static void tc3589x_gpio_irq_sync_unlock(struct irq_data *d)
 static void tc3589x_gpio_irq_mask(struct irq_data *d)
 {
 	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - tc3589x_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -185,7 +204,7 @@ static void tc3589x_gpio_irq_mask(struct irq_data *d)
 static void tc3589x_gpio_irq_unmask(struct irq_data *d)
 {
 	struct tc3589x_gpio *tc3589x_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - tc3589x_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -222,8 +241,9 @@ static irqreturn_t tc3589x_gpio_irq(int irq, void *dev)
 		while (stat) {
 			int bit = __ffs(stat);
 			int line = i * 8 + bit;
+			int virq = tc3589x_gpio_irq_get_virq(tc3589x_gpio, line);
 
-			handle_nested_irq(tc3589x_gpio->irq_base + line);
+			handle_nested_irq(virq);
 			stat &= ~(1 << bit);
 		}
 
@@ -233,38 +253,60 @@ static irqreturn_t tc3589x_gpio_irq(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
-static int tc3589x_gpio_irq_init(struct tc3589x_gpio *tc3589x_gpio)
+static int tc3589x_gpio_irq_map(struct irq_domain *d, unsigned int virq,
+				irq_hw_number_t hwirq)
 {
-	int base = tc3589x_gpio->irq_base;
-	int irq;
+	struct tc3589x *tc3589x_gpio = d->host_data;
 
-	for (irq = base; irq < base + tc3589x_gpio->chip.ngpio; irq++) {
-		irq_set_chip_data(irq, tc3589x_gpio);
-		irq_set_chip_and_handler(irq, &tc3589x_gpio_irq_chip,
+	irq_set_chip_data(virq, tc3589x_gpio);
+	irq_set_chip_and_handler(virq, &tc3589x_gpio_irq_chip,
 				handle_simple_irq);
-		irq_set_nested_thread(irq, 1);
+	irq_set_nested_thread(virq, 1);
 #ifdef CONFIG_ARM
-		set_irq_flags(irq, IRQF_VALID);
+	set_irq_flags(virq, IRQF_VALID);
 #else
-		irq_set_noprobe(irq);
+	irq_set_noprobe(virq);
 #endif
-	}
 
 	return 0;
 }
 
-static void tc3589x_gpio_irq_remove(struct tc3589x_gpio *tc3589x_gpio)
+static void tc3589x_gpio_irq_unmap(struct irq_domain *d, unsigned int virq)
 {
-	int base = tc3589x_gpio->irq_base;
-	int irq;
-
-	for (irq = base; irq < base + tc3589x_gpio->chip.ngpio; irq++) {
 #ifdef CONFIG_ARM
-		set_irq_flags(irq, 0);
+	set_irq_flags(virq, 0);
 #endif
-		irq_set_chip_and_handler(irq, NULL, NULL);
-		irq_set_chip_data(irq, NULL);
+	irq_set_chip_and_handler(virq, NULL, NULL);
+	irq_set_chip_data(virq, NULL);
+}
+
+static struct irq_domain_ops tc3589x_irq_ops = {
+        .map    = tc3589x_gpio_irq_map,
+        .unmap  = tc3589x_gpio_irq_unmap,
+        .xlate  = irq_domain_xlate_twocell,
+};
+
+static int tc3589x_gpio_irq_init(struct tc3589x_gpio *tc3589x_gpio)
+{
+	int base = tc3589x_gpio->irq_base;
+
+	if (base) {
+		tc3589x_gpio->domain = irq_domain_add_legacy(
+			NULL, tc3589x_gpio->chip.ngpio, base,
+			0, &tc3589x_irq_ops, tc3589x_gpio);
 	}
+	else {
+		tc3589x_gpio->domain = irq_domain_add_linear(
+			NULL, tc3589x_gpio->chip.ngpio,
+			&tc3589x_irq_ops, tc3589x_gpio);
+	}
+
+	if (!tc3589x_gpio->domain) {
+		dev_err(tc3589x_gpio->dev, "Failed to create irqdomain\n");
+		return -ENOSYS;
+	}
+
+	return 0;
 }
 
 static int __devinit tc3589x_gpio_probe(struct platform_device *pdev)
@@ -299,6 +341,9 @@ static int __devinit tc3589x_gpio_probe(struct platform_device *pdev)
 
 	tc3589x_gpio->irq_base = tc3589x->irq_base + TC3589x_INT_GPIO(0);
 
+	tc3589x_gpio->irq_base = tc3589x->irq_base ?
+		tc3589x->irq_base + TC3589x_INT_GPIO(0) : 0;
+
 	/* Bring the GPIO module out of reset */
 	ret = tc3589x_set_bits(tc3589x, TC3589x_RSTCTRL,
 			       TC3589x_RSTCTRL_GPIRST, 0);
@@ -313,7 +358,7 @@ static int __devinit tc3589x_gpio_probe(struct platform_device *pdev)
 				   "tc3589x-gpio", tc3589x_gpio);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
-		goto out_removeirq;
+		goto out_free;
 	}
 
 	ret = gpiochip_add(&tc3589x_gpio->chip);
@@ -331,8 +376,6 @@ static int __devinit tc3589x_gpio_probe(struct platform_device *pdev)
 
 out_freeirq:
 	free_irq(irq, tc3589x_gpio);
-out_removeirq:
-	tc3589x_gpio_irq_remove(tc3589x_gpio);
 out_free:
 	kfree(tc3589x_gpio);
 	return ret;
@@ -357,7 +400,6 @@ static int __devexit tc3589x_gpio_remove(struct platform_device *pdev)
 	}
 
 	free_irq(irq, tc3589x_gpio);
-	tc3589x_gpio_irq_remove(tc3589x_gpio);
 
 	platform_set_drvdata(pdev, NULL);
 	kfree(tc3589x_gpio);