staging: comedi: me_daq: tidy up dac control register defines

Redefine the dac control register bits as macros that take the
channel number and return the correct bit values.

This register needs to be read after the new values are written
in order to actually update the dac. For aesthetics, use the same
define to read and write the registers.
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/me_daq.c

@@ -89,24 +89,12 @@
 #define   ME_AI_FIFO_CHANLIST_UNIPOLAR	BIT(6)
 #define   ME_AI_FIFO_CHANLIST_GAIN(x)	(((x) & 0x3) << 4)
 #define   ME_AI_FIFO_CHANLIST_CHAN(x)	(((x) & 0xf) << 0)
-#define ME_DAC_CONTROL			0x0012	/* - | W */
-#define   DAC_UNIPOLAR_D		(0<<4)
-#define   DAC_BIPOLAR_D			(1<<4)
-#define   DAC_UNIPOLAR_C		(0<<5)
-#define   DAC_BIPOLAR_C			(1<<5)
-#define   DAC_UNIPOLAR_B		(0<<6)
-#define   DAC_BIPOLAR_B			(1<<6)
-#define   DAC_UNIPOLAR_A		(0<<7)
-#define   DAC_BIPOLAR_A			(1<<7)
-#define   DAC_GAIN_0_D			(0<<8)
-#define   DAC_GAIN_1_D			(1<<8)
-#define   DAC_GAIN_0_C			(0<<9)
-#define   DAC_GAIN_1_C			(1<<9)
-#define   DAC_GAIN_0_B			(0<<10)
-#define   DAC_GAIN_1_B			(1<<10)
-#define   DAC_GAIN_0_A			(0<<11)
-#define   DAC_GAIN_1_A			(1<<11)
-#define ME_DAC_CONTROL_UPDATE		0x0012	/* R | - */
+#define ME_DAC_CTRL_REG			0x12	/* R (updates) | W */
+#define   ME_DAC_CTRL_BIPOLAR(x)	BIT(7 - ((x) & 0x3))
+#define   ME_DAC_CTRL_GAIN(x)		BIT(11 - ((x) & 0x3))
+#define   ME_DAC_CTRL_MASK(x)		(ME_DAC_CTRL_BIPOLAR(x) |	\
+					 ME_DAC_CTRL_GAIN(x))
+
 #define ME_DAC_DATA_A			0x0014	/* - | W */
 #define ME_DAC_DATA_B			0x0016	/* - | W */
 #define ME_DAC_DATA_C			0x0018	/* - | W */
@@ -318,7 +306,7 @@ static int me_ao_insn_write(struct comedi_device *dev,
 {
 	struct me_private_data *devpriv = dev->private;
 	unsigned int chan = CR_CHAN(insn->chanspec);
-	unsigned int rang = CR_RANGE(insn->chanspec);
+	unsigned int range = CR_RANGE(insn->chanspec);
 	unsigned int val = s->readback[chan];
 	int i;
 
@@ -333,18 +321,17 @@ static int me_ao_insn_write(struct comedi_device *dev,
 	/* Set dac-control register */
 	for (i = 0; i < insn->n; i++) {
 		/* clear bits for this channel */
-		devpriv->dac_ctrl &= ~(0x0880 >> chan);
-		if (rang == 0)
-			devpriv->dac_ctrl |=
-			    ((DAC_BIPOLAR_A | DAC_GAIN_1_A) >> chan);
-		else if (rang == 1)
-			devpriv->dac_ctrl |=
-			    ((DAC_BIPOLAR_A | DAC_GAIN_0_A) >> chan);
+		devpriv->dac_ctrl &= ~ME_DAC_CTRL_MASK(chan);
+		if (range == 0)
+			devpriv->dac_ctrl |= ME_DAC_CTRL_GAIN(chan) |
+					     ME_DAC_CTRL_BIPOLAR(chan);
+		else if (range == 1)
+			devpriv->dac_ctrl |= ME_DAC_CTRL_BIPOLAR(chan);
 	}
-	writew(devpriv->dac_ctrl, dev->mmio + ME_DAC_CONTROL);
+	writew(devpriv->dac_ctrl, dev->mmio + ME_DAC_CTRL_REG);
 
 	/* Update dac-control register */
-	readw(dev->mmio + ME_DAC_CONTROL_UPDATE);
+	readw(dev->mmio + ME_DAC_CTRL_REG);
 
 	/* Set data register */
 	for (i = 0; i < insn->n; i++) {
@@ -438,7 +425,7 @@ static int me_reset(struct comedi_device *dev)
 	writew(0x00, dev->mmio + ME_CTRL1_REG);
 	writew(0x00, dev->mmio + ME_CTRL2_REG);
 	writew(0x00, dev->mmio + ME_STATUS_REG);	/* clear interrupts */
-	writew(0x00, dev->mmio + ME_DAC_CONTROL);
+	writew(0x00, dev->mmio + ME_DAC_CTRL_REG);
 
 	/* Save values in the board context */
 	devpriv->dac_ctrl = 0;