staging: comedi: pcl818: cleanup setup_channel_list()

Move this function to remove the need for the forward declaration. Rename it
so it has namespace associated with the driver. Remove the unnecessary
comedi_subdevice parameter from the function.

The hardware has per-channel programmable gain. This function first sets the
range for each channel then sets the mux register to automatically scan the
channels.

The use of 'muxonechan' when programming the ranges is incorrect. Only the low
4-bits are supposed to be set when programming the ranges.

Introduce a couple helper functions to set the range for a channel and to set
the first/last channels to scan.

Tidy up the range and mux register defines.
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/pcl818.c

@@ -119,10 +119,6 @@ A word or two about DMA. Driver support DMA operations at two ways:
 #define boardPCL818 4
 #define boardPCL718 5
 
-/* R: A/D high byte W: A/D range control */
-#define PCL818_RANGE 1
-/* R: next mux scan channel W: mux scan channel & range control pointer */
-#define PCL818_MUX 2
 /* R/W: operation control register */
 #define PCL818_CONTROL 9
 /* W: counter enable */
@@ -130,6 +126,9 @@ A word or two about DMA. Driver support DMA operations at two ways:
 
 #define PCL818_AI_LSB_REG			0x00
 #define PCL818_AI_MSB_REG			0x01
+#define PCL818_RANGE_REG			0x01
+#define PCL818_MUX_REG				0x02
+#define PCL818_MUX_SCAN(_first, _last)		(((_last) << 4) | (_first))
 #define PCL818_DO_DI_LSB_REG			0x03
 #define PCL818_AO_LSB_REG(x)			(0x04 + ((x) * 2))
 #define PCL818_AO_MSB_REG(x)			(0x05 + ((x) * 2))
@@ -317,14 +316,6 @@ struct pcl818_private {
 	unsigned int ai_cmd_canceled:1;
 };
 
-static const unsigned int muxonechan[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,	/*  used for gain list programming */
-	0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
-};
-
-static void setup_channel_list(struct comedi_device *dev,
-			       struct comedi_subdevice *s,
-			       unsigned int *chanlist, unsigned int n_chan,
-			       unsigned int seglen);
 static int check_channel_list(struct comedi_device *dev,
 			      struct comedi_subdevice *s,
 			      unsigned int *chanlist, unsigned int n_chan);
@@ -399,6 +390,50 @@ static void pcl818_ai_setup_next_dma(struct comedi_device *dev,
 	devpriv->dma_runs_to_end--;
 }
 
+static void pcl818_ai_set_chan_range(struct comedi_device *dev,
+				     unsigned int chan,
+				     unsigned int range)
+{
+	outb(chan, dev->iobase + PCL818_MUX_REG);
+	outb(range, dev->iobase + PCL818_RANGE_REG);
+}
+
+static void pcl818_ai_set_chan_scan(struct comedi_device *dev,
+				    unsigned int first_chan,
+				    unsigned int last_chan)
+{
+	outb(PCL818_MUX_SCAN(first_chan, last_chan),
+	     dev->iobase + PCL818_MUX_REG);
+}
+
+static void pcl818_ai_setup_chanlist(struct comedi_device *dev,
+				     unsigned int *chanlist,
+				     unsigned int seglen)
+{
+	struct pcl818_private *devpriv = dev->private;
+	unsigned int first_chan = CR_CHAN(chanlist[0]);
+	unsigned int last_chan;
+	unsigned int range;
+	int i;
+
+	devpriv->act_chanlist_len = seglen;
+	devpriv->act_chanlist_pos = 0;
+
+	/* store range list to card */
+	for (i = 0; i < seglen; i++) {
+		last_chan = CR_CHAN(chanlist[i]);
+		range = CR_RANGE(chanlist[i]);
+
+		devpriv->act_chanlist[i] = last_chan;
+
+		pcl818_ai_set_chan_range(dev, last_chan, range);
+	}
+
+	udelay(1);
+
+	pcl818_ai_set_chan_scan(dev, first_chan, last_chan);
+}
+
 static void pcl818_ai_clear_eoc(struct comedi_device *dev)
 {
 	/* writing any value clears the interrupt request */
@@ -662,7 +697,7 @@ static int pcl818_ai_cmd_mode(int mode, struct comedi_device *dev,
 	seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len);
 	if (seglen < 1)
 		return -EINVAL;
-	setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len, seglen);
+	pcl818_ai_setup_chanlist(dev, cmd->chanlist, seglen);
 
 	udelay(1);
 
@@ -760,31 +795,6 @@ static int check_channel_list(struct comedi_device *dev,
 	return seglen;
 }
 
-static void setup_channel_list(struct comedi_device *dev,
-			       struct comedi_subdevice *s,
-			       unsigned int *chanlist, unsigned int n_chan,
-			       unsigned int seglen)
-{
-	struct pcl818_private *devpriv = dev->private;
-	int i;
-
-	devpriv->act_chanlist_len = seglen;
-	devpriv->act_chanlist_pos = 0;
-
-	for (i = 0; i < seglen; i++) {	/*  store range list to card */
-		devpriv->act_chanlist[i] = CR_CHAN(chanlist[i]);
-		outb(muxonechan[CR_CHAN(chanlist[i])], dev->iobase + PCL818_MUX);	/* select channel */
-		outb(CR_RANGE(chanlist[i]), dev->iobase + PCL818_RANGE);	/* select gain */
-	}
-
-	udelay(1);
-
-	/* select channel interval to scan */
-	outb(devpriv->act_chanlist[0] | (devpriv->act_chanlist[seglen -
-							       1] << 4),
-	     dev->iobase + PCL818_MUX);
-}
-
 static int check_single_ended(unsigned int port)
 {
 	if (inb(port + PCL818_STATUS_REG) & PCL818_STATUS_MUX)
@@ -948,10 +958,8 @@ static int pcl818_ai_insn_read(struct comedi_device *dev,
 	/* software trigger, DMA and INT off */
 	outb(0, dev->iobase + PCL818_CONTROL);
 
-	/* select channel */
-	outb(muxonechan[chan], dev->iobase + PCL818_MUX);
-	/* select gain */
-	outb(range, dev->iobase + PCL818_RANGE);
+	pcl818_ai_set_chan_range(dev, chan, range);
+	pcl818_ai_set_chan_scan(dev, chan, chan);
 
 	for (i = 0; i < insn->n; i++) {
 		pcl818_ai_clear_eoc(dev);
@@ -1049,7 +1057,7 @@ static void pcl818_reset(struct comedi_device *dev)
 	udelay(1);
 	outb(0, dev->iobase + PCL818_CONTROL);
 	outb(0, dev->iobase + PCL818_CNTENABLE);
-	outb(0, dev->iobase + PCL818_MUX);
+	outb(0, dev->iobase + PCL818_MUX_REG);
 	pcl818_ai_clear_eoc(dev);
 
 	/* Stop pacer */
@@ -1058,7 +1066,7 @@ static void pcl818_reset(struct comedi_device *dev)
 	i8254_set_mode(timer_base, 0, 0, I8254_MODE0 | I8254_BINARY);
 
 	if (board->is_818) {
-		outb(0, dev->iobase + PCL818_RANGE);
+		outb(0, dev->iobase + PCL818_RANGE_REG);
 	} else {
 		/* set analog output channel 1 to 0V */
 		outb(0, dev->iobase + PCL818_AO_LSB_REG(1));