[PATCH 08/15] staging: comedi: addi_apci_1564: fix counter code in main driver source

[H Hartley Sweeten]

The Rev 1.0 APCI-1564 boards do not have counters.

Fix the code in the main driver source so that the I/O accesses to the
counters do not happen if the devpriv->counters member is not initialized.

This does not fix the code in hwdrv_apci1564.c. That code violates the
comedi API and is currently broken.

Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/staging/comedi/drivers/addi_apci_1564.c | 44 ++++++++++++++-----------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/drivers/staging/comedi/drivers/addi_apci_1564.c b/drivers/staging/comedi/drivers/addi_apci_1564.c
index b74e6c6..3fb9cc0 100644
--- a/drivers/staging/comedi/drivers/addi_apci_1564.c
+++ b/drivers/staging/comedi/drivers/addi_apci_1564.c
@@ -141,10 +141,12 @@ static int apci1564_reset(struct comedi_device *dev)
 	outl(0x0, devpriv->timer + APCI1564_TIMER_CTRL_REG);
 	outl(0x0, devpriv->timer + APCI1564_TIMER_RELOAD_REG);
 
-	/* Reset the counter registers */
-	outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(0));
-	outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(1));
-	outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(2));
+	if (devpriv->counters) {
+		/* Reset the counter registers */
+		outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(0));
+		outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(1));
+		outl(0x0, devpriv->counters + APCI1564_COUNTER_CTRL_REG(2));
+	}
 
 	return 0;
 }
@@ -186,22 +188,24 @@ static irqreturn_t apci1564_interrupt(int irq, void *d)
 		outl(ctrl, devpriv->timer + APCI1564_TIMER_CTRL_REG);
 	}
 
-	for (chan = 0; chan < 4; chan++) {
-		status = inl(devpriv->counters +
-			     APCI1564_COUNTER_IRQ_REG(chan));
-		if (status & 0x01) {
-			/*  Disable Counter Interrupt */
-			ctrl = inl(devpriv->counters +
-				   APCI1564_COUNTER_CTRL_REG(chan));
-			outl(0x0, devpriv->counters +
-			     APCI1564_COUNTER_CTRL_REG(chan));
-
-			/* Send a signal to from kernel to user space */
-			send_sig(SIGIO, devpriv->tsk_current, 0);
-
-			/*  Enable Counter Interrupt */
-			outl(ctrl, devpriv->counters +
-			     APCI1564_COUNTER_CTRL_REG(chan));
+	if (devpriv->counters) {
+		for (chan = 0; chan < 4; chan++) {
+			status = inl(devpriv->counters +
+				     APCI1564_COUNTER_IRQ_REG(chan));
+			if (status & 0x01) {
+				/*  Disable Counter Interrupt */
+				ctrl = inl(devpriv->counters +
+					   APCI1564_COUNTER_CTRL_REG(chan));
+				outl(0x0, devpriv->counters +
+				          APCI1564_COUNTER_CTRL_REG(chan));
+
+				/* Send a signal to from kernel to user space */
+				send_sig(SIGIO, devpriv->tsk_current, 0);
+
+				/*  Enable Counter Interrupt */
+				outl(ctrl, devpriv->counters +
+					   APCI1564_COUNTER_CTRL_REG(chan));
+			}
 		}
 	}
 
-- 
2.0.3