staging: comedi: ni_labpc: fix 8254 timer programming

As pointed out by Ian Abbott, the i8254_load() function does not
use the I8254_MODE* values to specify the "mode".

The labpc_counter_load() function in this driver is passed an
I8254_MODE* value so we need to use the i8254_set_mode() and
i8254_write() helpers instead of i8254_load() to program the
timers.

The calls to labpc_counter_load() will not fail so change the
return to void and remove all the unnecessary error handling.

Similarly, change the return type of labpc_counter_set_mode() to
void and remove the unnecessary error handling.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_labpc.c

@@ -171,32 +171,39 @@ static const struct labpc_boardinfo labpc_boards[] = {
 };
 #endif
 
-static int labpc_counter_load(struct comedi_device *dev,
+static void labpc_counter_load(struct comedi_device *dev,
 			       unsigned long base_address,
 			       unsigned int counter_number,
-			      unsigned int count, unsigned int mode)
+			       unsigned int count,
+			       unsigned int mode)
 {
 	const struct labpc_boardinfo *board = comedi_board(dev);
 
-	if (board->has_mmio)
-		return i8254_mm_load((void __iomem *)base_address, 0,
-				     counter_number, count, mode);
-	else
-		return i8254_load(base_address, 0, counter_number, count, mode);
+	if (board->has_mmio) {
+		void __iomem *mmio_base = (void __iomem *)base_address;
+
+		i8254_mm_set_mode(mmio_base, 0, counter_number, mode);
+		i8254_mm_write(mmio_base, 0, counter_number, count);
+	} else {
+		i8254_set_mode(base_address, 0, counter_number, mode);
+		i8254_write(base_address, 0, counter_number, count);
+	}
 }
 
-static int labpc_counter_set_mode(struct comedi_device *dev,
+static void labpc_counter_set_mode(struct comedi_device *dev,
 				   unsigned long base_address,
 				   unsigned int counter_number,
 				   unsigned int mode)
 {
 	const struct labpc_boardinfo *board = comedi_board(dev);
 
-	if (board->has_mmio)
-		return i8254_mm_set_mode((void __iomem *)base_address, 0,
-					 counter_number, mode);
-	else
-		return i8254_set_mode(base_address, 0, counter_number, mode);
+	if (board->has_mmio) {
+		void __iomem *mmio_base = (void __iomem *)base_address;
+
+		i8254_mm_set_mode(mmio_base, 0, counter_number, mode);
+	} else {
+		i8254_set_mode(base_address, 0, counter_number, mode);
+	}
 }
 
 static int labpc_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
@@ -349,10 +356,8 @@ static int labpc_ai_insn_read(struct comedi_device *dev,
 	devpriv->write_byte(devpriv->cmd4, dev->iobase + CMD4_REG);
 
 	/* initialize pacer counter to prevent any problems */
-	ret = labpc_counter_set_mode(dev, dev->iobase + COUNTER_A_BASE_REG,
+	labpc_counter_set_mode(dev, dev->iobase + COUNTER_A_BASE_REG,
 			       0, I8254_MODE2);
-	if (ret)
-		return ret;
 
 	labpc_clear_adc_fifo(dev);
 
@@ -730,7 +735,6 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	unsigned int aref = CR_AREF(chanspec);
 	enum transfer_type xfer;
 	unsigned long flags;
-	int ret;
 
 	/* make sure board is disabled before setting up acquisition */
 	labpc_cancel(dev, s);
@@ -745,18 +749,13 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 		 * load counter a1 with count of 3
 		 * (pc+ manual says this is minimum allowed) using mode 0
 		 */
-		ret = labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
+		labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
 				   1, 3, I8254_MODE0);
 	} else	{
 		/* just put counter a1 in mode 0 to set its output low */
-		ret = labpc_counter_set_mode(dev,
-					     dev->iobase + COUNTER_A_BASE_REG,
+		labpc_counter_set_mode(dev, dev->iobase + COUNTER_A_BASE_REG,
 				       1, I8254_MODE0);
 	}
-	if (ret) {
-		comedi_error(dev, "error loading counter a1");
-		return ret;
-	}
 
 	/* figure out what method we will use to transfer data */
 	if (labpc_have_dma_chan(dev) &&
@@ -800,38 +799,25 @@ static int labpc_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 		/*  set up pacing */
 		labpc_adc_timing(dev, cmd, mode);
 		/*  load counter b0 in mode 3 */
-		ret = labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
+		labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
 				   0, devpriv->divisor_b0, I8254_MODE3);
-		if (ret < 0) {
-			comedi_error(dev, "error loading counter b0");
-			return -1;
-		}
 	}
 	/*  set up conversion pacing */
 	if (labpc_ai_convert_period(cmd, mode)) {
 		/*  load counter a0 in mode 2 */
-		ret = labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
+		labpc_counter_load(dev, dev->iobase + COUNTER_A_BASE_REG,
 				   0, devpriv->divisor_a0, I8254_MODE2);
 	} else {
 		/* initialize pacer counter to prevent any problems */
-		ret = labpc_counter_set_mode(dev,
-					     dev->iobase + COUNTER_A_BASE_REG,
+		labpc_counter_set_mode(dev, dev->iobase + COUNTER_A_BASE_REG,
 				       0, I8254_MODE2);
 	}
-	if (ret) {
-		comedi_error(dev, "error loading counter a0");
-		return ret;
-	}
 
 	/*  set up scan pacing */
 	if (labpc_ai_scan_period(cmd, mode)) {
 		/*  load counter b1 in mode 2 */
-		ret = labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
+		labpc_counter_load(dev, dev->iobase + COUNTER_B_BASE_REG,
 				   1, devpriv->divisor_b1, I8254_MODE2);
-		if (ret < 0) {
-			comedi_error(dev, "error loading counter b1");
-			return -1;
-		}
 	}
 
 	labpc_clear_adc_fifo(dev);