gpio: Provide the STMPE GPIO driver with its own IRQ Domain

The STMPE GPIO driver can be used as an IRQ controller by some
related devices. Here we provide it with its very own IRQ Domain
so that IRQs can be issued dynamically. This will stand the
driver in good stead when it is enabled for Device Tree, as this
it a prerequisite.

Cc: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-stmpe.c

@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/gpio.h>
 #include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
 #include <linux/mfd/stmpe.h>
@@ -29,6 +30,7 @@ struct stmpe_gpio {
 	struct stmpe *stmpe;
 	struct device *dev;
 	struct mutex irq_lock;
+	struct irq_domain *domain;
 
 	int irq_base;
 	unsigned norequest_mask;
@@ -104,7 +106,7 @@ static int stmpe_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 {
 	struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
 
-	return stmpe_gpio->irq_base + offset;
+	return irq_create_mapping(stmpe_gpio->domain, offset);
 }
 
 static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
@@ -133,7 +135,7 @@ static struct gpio_chip template_chip = {
 static int stmpe_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 {
 	struct stmpe_gpio *stmpe_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - stmpe_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -200,7 +202,7 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d)
 static void stmpe_gpio_irq_mask(struct irq_data *d)
 {
 	struct stmpe_gpio *stmpe_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - stmpe_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -210,7 +212,7 @@ static void stmpe_gpio_irq_mask(struct irq_data *d)
 static void stmpe_gpio_irq_unmask(struct irq_data *d)
 {
 	struct stmpe_gpio *stmpe_gpio = irq_data_get_irq_chip_data(d);
-	int offset = d->irq - stmpe_gpio->irq_base;
+	int offset = d->hwirq;
 	int regoffset = offset / 8;
 	int mask = 1 << (offset % 8);
 
@@ -252,8 +254,9 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 		while (stat) {
 			int bit = __ffs(stat);
 			int line = bank * 8 + bit;
+			int virq = irq_find_mapping(stmpe_gpio->domain, line);
 
-			handle_nested_irq(stmpe_gpio->irq_base + line);
+			handle_nested_irq(virq);
 			stat &= ~(1 << bit);
 		}
 
@@ -268,38 +271,55 @@ static irqreturn_t stmpe_gpio_irq(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
-static int __devinit stmpe_gpio_irq_init(struct stmpe_gpio *stmpe_gpio)
+int stmpe_gpio_irq_map(struct irq_domain *d, unsigned int virq,
+		       irq_hw_number_t hwirq)
 {
-	int base = stmpe_gpio->irq_base;
-	int irq;
+	struct stmpe_gpio *stmpe_gpio = d->host_data;
+
+	if (!stmpe_gpio)
+		return -EINVAL;
 
-	for (irq = base; irq < base + stmpe_gpio->chip.ngpio; irq++) {
-		irq_set_chip_data(irq, stmpe_gpio);
-		irq_set_chip_and_handler(irq, &stmpe_gpio_irq_chip,
-					 handle_simple_irq);
-		irq_set_nested_thread(irq, 1);
+	irq_set_chip_data(hwirq, stmpe_gpio);
+	irq_set_chip_and_handler(hwirq, &stmpe_gpio_irq_chip,
+				 handle_simple_irq);
+	irq_set_nested_thread(hwirq, 1);
 #ifdef CONFIG_ARM
-		set_irq_flags(irq, IRQF_VALID);
+	set_irq_flags(hwirq, IRQF_VALID);
 #else
-		irq_set_noprobe(irq);
+	irq_set_noprobe(hwirq);
 #endif
-	}
 
 	return 0;
 }
 
-static void stmpe_gpio_irq_remove(struct stmpe_gpio *stmpe_gpio)
+void stmpe_gpio_irq_unmap(struct irq_domain *d, unsigned int virq)
 {
-	int base = stmpe_gpio->irq_base;
-	int irq;
-
-	for (irq = base; irq < base + stmpe_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 const struct irq_domain_ops stmpe_gpio_irq_simple_ops = {
+	.unmap = stmpe_gpio_irq_unmap,
+	.map = stmpe_gpio_irq_map,
+	.xlate = irq_domain_xlate_twocell,
+};
+
+static int __devinit stmpe_gpio_irq_init(struct stmpe_gpio *stmpe_gpio)
+{
+	int base = stmpe_gpio->irq_base;
+
+	stmpe_gpio->domain = irq_domain_add_simple(NULL,
+				stmpe_gpio->chip.ngpio, base,
+				&stmpe_gpio_irq_simple_ops, stmpe_gpio);
+	if (!stmpe_gpio->domain) {
+		dev_err(stmpe_gpio->dev, "failed to create irqdomain\n");
+		return -ENOSYS;
 	}
+
+	return 0;
 }
 
 static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
@@ -354,7 +374,7 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 				IRQF_ONESHOT, "stmpe-gpio", stmpe_gpio);
 		if (ret) {
 			dev_err(&pdev->dev, "unable to get irq: %d\n", ret);
-			goto out_removeirq;
+			goto out_disable;
 		}
 	}
 
@@ -374,9 +394,6 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 out_freeirq:
 	if (irq >= 0)
 		free_irq(irq, stmpe_gpio);
-out_removeirq:
-	if (irq >= 0)
-		stmpe_gpio_irq_remove(stmpe_gpio);
 out_disable:
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 out_free:
@@ -404,10 +421,9 @@ static int __devexit stmpe_gpio_remove(struct platform_device *pdev)
 
 	stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
 
-	if (irq >= 0) {
+	if (irq >= 0)
 		free_irq(irq, stmpe_gpio);
-		stmpe_gpio_irq_remove(stmpe_gpio);
-	}
+
 	platform_set_drvdata(pdev, NULL);
 	kfree(stmpe_gpio);