diff --git a/drivers/staging/comedi/drivers/addi_apci_3120.c b/drivers/staging/comedi/drivers/addi_apci_3120.c
index 358bfd3f3417..cc561788e740 100644
--- a/drivers/staging/comedi/drivers/addi_apci_3120.c
+++ b/drivers/staging/comedi/drivers/addi_apci_3120.c
@@ -168,23 +168,23 @@ static int apci3120_auto_attach(struct comedi_device *dev,
 	if (ret)
 		return ret;
 
-	/*  Allocate and Initialise AI Subdevice Structures */
+	/* Analog Input subdevice */
 	s = &dev->subdevices[0];
-	dev->read_subdev = s;
-	s->type = COMEDI_SUBD_AI;
-	s->subdev_flags =
-		SDF_READABLE | SDF_COMMON | SDF_GROUND
-		| SDF_DIFF;
-	s->n_chan = 16;
-	s->maxdata = this_board->ai_is_16bit ? 0xffff : 0x0fff;
-	s->len_chanlist = s->n_chan;
-	s->range_table = &range_apci3120_ai;
-
-	s->insn_config = apci3120_ai_insn_config;
-	s->insn_read = apci3120_ai_insn_read;
-	s->do_cmdtest = apci3120_ai_cmdtest;
-	s->do_cmd = apci3120_ai_cmd;
-	s->cancel = apci3120_cancel;
+	s->type		= COMEDI_SUBD_AI;
+	s->subdev_flags	= SDF_READABLE | SDF_COMMON | SDF_GROUND | SDF_DIFF;
+	s->n_chan	= 16;
+	s->maxdata	= this_board->ai_is_16bit ? 0xffff : 0x0fff;
+	s->range_table	= &range_apci3120_ai;
+	s->insn_config	= apci3120_ai_insn_config;
+	s->insn_read	= apci3120_ai_insn_read;
+	if (0 /* dev->irq */) {
+		dev->read_subdev = s;
+		s->subdev_flags	|= SDF_CMD_READ;
+		s->len_chanlist	= s->n_chan;
+		s->do_cmdtest	= apci3120_ai_cmdtest;
+		s->do_cmd	= apci3120_ai_cmd;
+		s->cancel	= apci3120_cancel;
+	}
 
 	/* Analog Output subdevice */
 	s = &dev->subdevices[1];