mfd: Allocate twl6040 IRQ numbers dynamically

Use irq_alloc_descs() to get the IRQ number range dynamically instead of
the hardwired use if pdata->irq_base.
The twl6040 only provides interrupts for it's internal components which
means that it is not working as an IRQ expander type of device.
The client drivers will receive their interrupt numbers as resource which
is configured based on the received IRQ range we got from irq_alloc_descs()

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/twl6040-core.c

@@ -515,7 +515,7 @@ static int __devinit twl6040_probe(struct i2c_client *client,
 	}
 
 	/* In order to operate correctly we need valid interrupt config */
-	if (!client->irq || !pdata->irq_base) {
+	if (!client->irq) {
 		dev_err(&client->dev, "Invalid IRQ configuration\n");
 		return -EINVAL;
 	}
@@ -552,7 +552,6 @@ static int __devinit twl6040_probe(struct i2c_client *client,
 
 	twl6040->dev = &client->dev;
 	twl6040->irq = client->irq;
-	twl6040->irq_base = pdata->irq_base;
 
 	mutex_init(&twl6040->mutex);
 	mutex_init(&twl6040->io_mutex);

drivers/mfd/twl6040-irq.c

@@ -23,6 +23,7 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/err.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/core.h>
@@ -138,7 +139,7 @@ static irqreturn_t twl6040_irq_thread(int irq, void *data)
 
 int twl6040_irq_init(struct twl6040 *twl6040)
 {
-	int i, nr_irqs, ret;
+	int i, nr_irqs, irq_base, ret;
 	u8 val;
 
 	mutex_init(&twl6040->irq_mutex);
@@ -149,8 +150,16 @@ int twl6040_irq_init(struct twl6040 *twl6040)
 	twl6040_reg_write(twl6040, TWL6040_REG_INTMR, TWL6040_ALLINT_MSK);
 
 	nr_irqs = ARRAY_SIZE(twl6040_irqs);
+
+	irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
+	if (IS_ERR_VALUE(irq_base)) {
+		dev_err(twl6040->dev, "Fail to allocate IRQ descs\n");
+		return irq_base;
+	}
+	twl6040->irq_base = irq_base;
+
 	/* Register them with genirq */
-	for (i = twl6040->irq_base; i < twl6040->irq_base + nr_irqs; i++) {
+	for (i = irq_base; i < irq_base + nr_irqs; i++) {
 		irq_set_chip_data(i, twl6040);
 		irq_set_chip_and_handler(i, &twl6040_irq_chip,
 					 handle_level_irq);