diff --git a/drivers/staging/comedi/drivers/dmm32at.c b/drivers/staging/comedi/drivers/dmm32at.c
index 35a8f84867aaecde38afdb398b064c6f446fb209..e9cd2517ad8118cb1ee853db53252ea293da975a 100644
--- a/drivers/staging/comedi/drivers/dmm32at.c
+++ b/drivers/staging/comedi/drivers/dmm32at.c
@@ -40,9 +40,6 @@ Configuration Options:
 #include "comedi_fc.h"
 
 /* Board register addresses */
-
-#define DMM32AT_MEMSIZE 0x10
-
 #define DMM32AT_CONV 0x00
 #define DMM32AT_AILSB 0x00
 #define DMM32AT_AUXDOUT 0x01
@@ -684,7 +681,7 @@ static int dmm32at_attach(struct comedi_device *dev,
 	struct comedi_subdevice *s;
 	unsigned char aihi, ailo, fifostat, aistat, intstat, airback;
 
-	ret = comedi_request_region(dev, it->options[0], DMM32AT_MEMSIZE);
+	ret = comedi_request_region(dev, it->options[0], 0x10);
 	if (ret)
 		return ret;
 
diff --git a/drivers/staging/comedi/drivers/dt2801.c b/drivers/staging/comedi/drivers/dt2801.c
index 4263014426f83acfe7cbb9409cbad969cf3a2afb..ad8ba0be4878d10ff9a905a32bf785d8d17c9afb 100644
--- a/drivers/staging/comedi/drivers/dt2801.c
+++ b/drivers/staging/comedi/drivers/dt2801.c
@@ -40,9 +40,6 @@ Configuration options:
 
 #define DT2801_MAX_DMA_SIZE (64 * 1024)
 
-/* Ports */
-#define DT2801_IOSIZE 2
-
 /* define's */
 /* ====================== */
 
@@ -552,7 +549,7 @@ static int dt2801_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	int ret = 0;
 	int n_ai_chans;
 
-	ret = comedi_request_region(dev, it->options[0], DT2801_IOSIZE);
+	ret = comedi_request_region(dev, it->options[0], 0x2);
 	if (ret)
 		return ret;
 
diff --git a/drivers/staging/comedi/drivers/rti800.c b/drivers/staging/comedi/drivers/rti800.c
index bd447b2add7b74e3935a755938e3342bd9f68b0a..2b1db9783bd6489181d5c689927b16e101285ae3 100644
--- a/drivers/staging/comedi/drivers/rti800.c
+++ b/drivers/staging/comedi/drivers/rti800.c
@@ -81,8 +81,6 @@
 #define RTI800_9513A_CNTRL	0x0d
 #define RTI800_9513A_STATUS	0x0d
 
-#define RTI800_IOSIZE		0x10
-
 static const struct comedi_lrange range_rti800_ai_10_bipolar = {
 	4, {
 		BIP_RANGE(10),
@@ -281,7 +279,7 @@ static int rti800_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	struct comedi_subdevice *s;
 	int ret;
 
-	ret = comedi_request_region(dev, it->options[0], RTI800_IOSIZE);
+	ret = comedi_request_region(dev, it->options[0], 0x10);
 	if (ret)
 		return ret;