diff --git a/drivers/iio/adc/ad7780.c b/drivers/iio/adc/ad7780.c
index 74c85bd566e5..217a5a5c3c6d 100644
--- a/drivers/iio/adc/ad7780.c
+++ b/drivers/iio/adc/ad7780.c
@@ -206,9 +206,9 @@ static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
 };
 
 #define AD7780_CHANNEL(bits, wordsize) \
-	AD_SD_CHANNEL(1, 0, 0, bits, 32, wordsize - bits)
+	AD_SD_CHANNEL(1, 0, 0, bits, 32, (wordsize) - (bits))
 #define AD7170_CHANNEL(bits, wordsize) \
-	AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, wordsize - bits)
+	AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, (wordsize) - (bits))
 
 static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
 	[ID_AD7170] = {