Staging: ipack/bridges/tpci200: Cleanup in tpci200_slot_irq() and tpci200_interrupt()

Minor cleanup.  No functional changes.
Signed-off-by: NJens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: NSamuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ipack/bridges/tpci200.c

@@ -102,9 +102,13 @@ static void tpci200_unregister(struct tpci200_board *tpci200)
 
 static irqreturn_t tpci200_slot_irq(struct slot_irq *slot_irq)
 {
-	irqreturn_t ret = slot_irq->handler(slot_irq->arg);
+	irqreturn_t ret;
 
-	/* Dummy reads */
+	if (!slot_irq)
+		return -ENODEV;
+	ret = slot_irq->handler(slot_irq->arg);
+
+	/* Clear the IPack device interrupt */
 	readw(slot_irq->holder->io_space.address + 0xC0);
 	readw(slot_irq->holder->io_space.address + 0xC2);
 
@@ -114,23 +118,26 @@ static irqreturn_t tpci200_slot_irq(struct slot_irq *slot_irq)
 static irqreturn_t tpci200_interrupt(int irq, void *dev_id)
 {
 	struct tpci200_board *tpci200 = (struct tpci200_board *) dev_id;
-	int i;
-	unsigned short status_reg;
 	struct slot_irq *slot_irq;
+	irqreturn_t ret;
+	u16 status_reg;
+	int i;
 
 	/* Read status register */
-	status_reg = readw(&tpci200->info->interface_regs->status);
+	status_reg = ioread16(&tpci200->info->interface_regs->status);
+
+	/* Did we cause the interrupt? */
+	if (!(status_reg & TPCI200_SLOT_INT_MASK))
+		return IRQ_NONE;
 
-	if (status_reg & TPCI200_SLOT_INT_MASK) {
 	/* callback to the IRQ handler for the corresponding slot */
 	rcu_read_lock();
 	for (i = 0; i < TPCI200_NB_SLOT; i++) {
-			if (!(status_reg & ((TPCI200_A_INT0 | TPCI200_A_INT1) << (2*i))))
+		if (!(status_reg & ((TPCI200_A_INT0 | TPCI200_A_INT1) << (2 * i))))
 			continue;
 		slot_irq = rcu_dereference(tpci200->slots[i].irq);
-			if (slot_irq) {
-				tpci200_slot_irq(slot_irq);
-			} else {
+		ret = tpci200_slot_irq(slot_irq);
+		if (ret == -ENODEV) {
 			dev_info(&tpci200->info->pdev->dev,
 				 "No registered ISR for slot [%d:%d]!. IRQ will be disabled.\n",
 				 tpci200->number, i);
@@ -142,9 +149,6 @@ static irqreturn_t tpci200_interrupt(int irq, void *dev_id)
 	rcu_read_unlock();
 
 	return IRQ_HANDLED;
-	} else {
-		return IRQ_NONE;
-	}
 }
 
 static int tpci200_register(struct tpci200_board *tpci200)