timbgpio: Add support for interrupt triggering on both flanks

["Richard Röjfors" <richard.rojfors@pelagicore.com>]

This patch introduces support for triggering interrupts on both rising
and falling edge.

This feature requires version 3 or newer of the IP, a version check is done
when triggering on both edges is requested.

Signed-off-by: Richard Röjfors <richard.rojfors@pelagicore.com>
---
diff --git a/drivers/gpio/timbgpio.c b/drivers/gpio/timbgpio.c
index a4d344b..471be03 100644
--- a/drivers/gpio/timbgpio.c
+++ b/drivers/gpio/timbgpio.c
@@ -37,6 +37,8 @@
 #define TGPIO_ICR	0x14
 #define TGPIO_FLR	0x18
 #define TGPIO_LVR	0x1c
+#define TGPIO_VER	0x20
+#define TGPIO_BFLR	0x24

 struct timbgpio {
 	void __iomem		*membase;
@@ -125,17 +127,23 @@ static int timbgpio_irq_type(unsigned irq, unsigned trigger)
 	struct timbgpio *tgpio = get_irq_chip_data(irq);
 	int offset = irq - tgpio->irq_base;
 	unsigned long flags;
-	u32 lvr, flr;
+	u32 lvr, flr, bflr = 0;
+	u32 ver;

 	if (offset < 0 || offset > tgpio->gpio.ngpio)
 		return -EINVAL;

+	ver = ioread32(tgpio->membase + TGPIO_VER);
+
 	spin_lock_irqsave(&tgpio->lock, flags);

 	lvr = ioread32(tgpio->membase + TGPIO_LVR);
 	flr = ioread32(tgpio->membase + TGPIO_FLR);
+	if (ver > 2)
+		bflr = ioread32(tgpio->membase + TGPIO_BFLR);

 	if (trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
+		bflr &= ~(1 << offset);
 		flr &= ~(1 << offset);
 		if (trigger & IRQ_TYPE_LEVEL_HIGH)
 			lvr |= 1 << offset;
@@ -143,21 +151,27 @@ static int timbgpio_irq_type(unsigned irq, unsigned trigger)
 			lvr &= ~(1 << offset);
 	}

-	if ((trigger & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
-		return -EINVAL;
-	else {
+	if ((trigger & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
+		if (ver < 3)
+			return -EINVAL;
+		else {
+			flr |= 1 << offset;
+			bflr |= 1 << offset;
+		}
+	} else {
+		bflr &= ~(1 << offset);
 		flr |= 1 << offset;
-		/* opposite compared to the datasheet, but it mirrors the
-		 * reality
-		 */
 		if (trigger & IRQ_TYPE_EDGE_FALLING)
-			lvr |= 1 << offset;
-		else
 			lvr &= ~(1 << offset);
+		else
+			lvr |= 1 << offset;
 	}

 	iowrite32(lvr, tgpio->membase + TGPIO_LVR);
 	iowrite32(flr, tgpio->membase + TGPIO_FLR);
+	if (ver > 2)
+		iowrite32(bflr, tgpio->membase + TGPIO_BFLR);
+
 	iowrite32(1 << offset, tgpio->membase + TGPIO_ICR);
 	spin_unlock_irqrestore(&tgpio->lock, flags);