diff --git a/drivers/staging/comedi/drivers/amplc_pci224.c b/drivers/staging/comedi/drivers/amplc_pci224.c
index 2e6decf1b69d..07555cffc414 100644
--- a/drivers/staging/comedi/drivers/amplc_pci224.c
+++ b/drivers/staging/comedi/drivers/amplc_pci224.c
@@ -216,8 +216,12 @@
 #define GAT_GND		1	/* GND (i.e. disabled) */
 #define GAT_EXT		2	/* reserved (external gate input) */
 #define GAT_NOUTNM2	3	/* inverted output of channel-2 modulo total */
-/* Macro to construct gate input configuration register value. */
-#define GAT_CONFIG(chan, src)	((((chan) & 3) << 3) | ((src) & 7))
+
+static inline unsigned int pci224_gat_config(unsigned int chan,
+					     unsigned int src)
+{
+	return ((chan & 3) << 3) | (src & 7);
+}
 
 /*
  * Summary of CLK_OUTNM1 and GAT_NOUTNM2 connections for PCI224 and PCI234:
@@ -817,10 +821,10 @@ static void pci224_ao_start_pacer(struct comedi_device *dev,
 	 * source.
 	 */
 	/* Make sure Z2-0 is gated on.  */
-	outb(GAT_CONFIG(0, GAT_VCC), devpriv->iobase1 + PCI224_ZGAT_SCE);
+	outb(pci224_gat_config(0, GAT_VCC), devpriv->iobase1 + PCI224_ZGAT_SCE);
 	/* Cascading with Z2-2. */
 	/* Make sure Z2-2 is gated on.  */
-	outb(GAT_CONFIG(2, GAT_VCC), devpriv->iobase1 + PCI224_ZGAT_SCE);
+	outb(pci224_gat_config(2, GAT_VCC), devpriv->iobase1 + PCI224_ZGAT_SCE);
 	/* Z2-2 needs 10 MHz clock. */
 	outb(CLK_CONFIG(2, CLK_10MHZ), devpriv->iobase1 + PCI224_ZCLK_SCE);
 	/* Z2-0 is clocked from Z2-2's output. */