mfd: Add irq domain support for max8997 interrupts

Add irq domain support for max8997 interrupts. The reverse mapping method
used is linear mapping since the sub-drivers of max8997 such as regulator
and charger drivers can use the max8997 irq_domain to get the linux irq
number for max8997 interrupts. All uses of irq_base in platform data and
max8997 driver private data are removed.

Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/max8997-irq.c

@@ -142,7 +142,8 @@ static void max8997_irq_sync_unlock(struct irq_data *data)
 static const inline struct max8997_irq_data *
 irq_to_max8997_irq(struct max8997_dev *max8997, int irq)
 {
-	return &max8997_irqs[irq - max8997->irq_base];
+	struct irq_data *data = irq_get_irq_data(irq);
+	return &max8997_irqs[data->hwirq];
 }
 
 static void max8997_irq_mask(struct irq_data *data)
@@ -182,7 +183,7 @@ static irqreturn_t max8997_irq_thread(int irq, void *data)
 	u8 irq_reg[MAX8997_IRQ_GROUP_NR] = {};
 	u8 irq_src;
 	int ret;
-	int i;
+	int i, cur_irq;
 
 	ret = max8997_read_reg(max8997->i2c, MAX8997_REG_INTSRC, &irq_src);
 	if (ret < 0) {
@@ -269,8 +270,11 @@ static irqreturn_t max8997_irq_thread(int irq, void *data)
 
 	/* Report */
 	for (i = 0; i < MAX8997_IRQ_NR; i++) {
-		if (irq_reg[max8997_irqs[i].group] & max8997_irqs[i].mask)
-			handle_nested_irq(max8997->irq_base + i);
+		if (irq_reg[max8997_irqs[i].group] & max8997_irqs[i].mask) {
+			cur_irq = irq_find_mapping(max8997->irq_domain, i);
+			if (cur_irq)
+				handle_nested_irq(cur_irq);
+		}
 	}
 
 	return IRQ_HANDLED;
@@ -278,26 +282,40 @@ static irqreturn_t max8997_irq_thread(int irq, void *data)
 
 int max8997_irq_resume(struct max8997_dev *max8997)
 {
-	if (max8997->irq && max8997->irq_base)
-		max8997_irq_thread(max8997->irq_base, max8997);
+	if (max8997->irq && max8997->irq_domain)
+		max8997_irq_thread(0, max8997);
 	return 0;
 }
 
+static int max8997_irq_domain_map(struct irq_domain *d, unsigned int irq,
+					irq_hw_number_t hw)
+{
+	struct max8997_dev *max8997 = d->host_data;
+
+	irq_set_chip_data(irq, max8997);
+	irq_set_chip_and_handler(irq, &max8997_irq_chip, handle_edge_irq);
+	irq_set_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+	set_irq_flags(irq, IRQF_VALID);
+#else
+	irq_set_noprobe(irq);
+#endif
+	return 0;
+}
+
+static struct irq_domain_ops max8997_irq_domain_ops = {
+	.map = max8997_irq_domain_map,
+};
+
 int max8997_irq_init(struct max8997_dev *max8997)
 {
+	struct irq_domain *domain;
 	int i;
-	int cur_irq;
 	int ret;
 	u8 val;
 
 	if (!max8997->irq) {
 		dev_warn(max8997->dev, "No interrupt specified.\n");
-		max8997->irq_base = 0;
-		return 0;
-	}
-
-	if (!max8997->irq_base) {
-		dev_err(max8997->dev, "No interrupt base specified.\n");
 		return 0;
 	}
 
@@ -327,19 +345,13 @@ int max8997_irq_init(struct max8997_dev *max8997)
 					true : false;
 	}
 
-	/* Register with genirq */
-	for (i = 0; i < MAX8997_IRQ_NR; i++) {
-		cur_irq = i + max8997->irq_base;
-		irq_set_chip_data(cur_irq, max8997);
-		irq_set_chip_and_handler(cur_irq, &max8997_irq_chip,
-				handle_edge_irq);
-		irq_set_nested_thread(cur_irq, 1);
-#ifdef CONFIG_ARM
-		set_irq_flags(cur_irq, IRQF_VALID);
-#else
-		irq_set_noprobe(cur_irq);
-#endif
+	domain = irq_domain_add_linear(NULL, MAX8997_IRQ_NR,
+					&max8997_irq_domain_ops, max8997);
+	if (!domain) {
+		dev_err(max8997->dev, "could not create irq domain\n");
+		return -ENODEV;
 	}
+	max8997->irq_domain = domain;
 
 	ret = request_threaded_irq(max8997->irq, NULL, max8997_irq_thread,
 			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,