staging: comedi: rtd520: sample types are unsigned
authorIan Abbott <abbotti@mev.co.uk>
Wed, 16 Oct 2013 13:40:35 +0000 (14:40 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 16 Oct 2013 19:48:31 +0000 (12:48 -0700)
Sample values in comedi are generally represented as unsigned values.
Use unsigned types for sample value manipulations in the "rtd520" driver
for consistency.

Also replace the hand-coded munging of 2's complement sample values with
calls to `comedi_offset_munge()` and AND with `s->maxdata` to strip off
any extra sign bits.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/comedi/drivers/rtd520.c

index 3ec6632949bd3d003f66ee20a3dd454ac9501d37..0ae2d6175471d4970a1b7f267581462684bb7842 100644 (file)
@@ -602,7 +602,7 @@ static int rtd_ai_rinsn(struct comedi_device *dev,
 
        /* convert n samples */
        for (n = 0; n < insn->n; n++) {
-               s16 d;
+               unsigned short d;
                /* trigger conversion */
                writew(0, devpriv->las0 + LAS0_ADC);
 
@@ -621,9 +621,8 @@ static int rtd_ai_rinsn(struct comedi_device *dev,
                d = d >> 3;     /* low 3 bits are marker lines */
                if (CHAN_ARRAY_TEST(devpriv->chan_is_bipolar, 0))
                        /* convert to comedi unsigned data */
-                       data[n] = d + 2048;
-               else
-                       data[n] = d;
+                       d = comedi_offset_munge(s, d);
+               data[n] = d & s->maxdata;
        }
 
        /* return the number of samples read/written */
@@ -643,8 +642,7 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
        int ii;
 
        for (ii = 0; ii < count; ii++) {
-               short sample;
-               s16 d;
+               unsigned short d;
 
                if (0 == devpriv->ai_count) {   /* done */
                        d = readw(devpriv->las1 + LAS1_ADC_FIFO);
@@ -654,13 +652,12 @@ static int ai_read_n(struct comedi_device *dev, struct comedi_subdevice *s,
                d = readw(devpriv->las1 + LAS1_ADC_FIFO);
                d = d >> 3;     /* low 3 bits are marker lines */
                if (CHAN_ARRAY_TEST(devpriv->chan_is_bipolar,
-                                   s->async->cur_chan)) {
+                                   s->async->cur_chan))
                        /* convert to comedi unsigned data */
-                       sample = d + 2048;
-               } else
-                       sample = d;
+                       d = comedi_offset_munge(s, d);
+               d &= s->maxdata;
 
-               if (!comedi_buf_put(s->async, sample))
+               if (!comedi_buf_put(s->async, d))
                        return -1;
 
                if (devpriv->ai_count > 0)      /* < 0, means read forever */
@@ -677,8 +674,7 @@ static int ai_read_dregs(struct comedi_device *dev, struct comedi_subdevice *s)
        struct rtd_private *devpriv = dev->private;
 
        while (readl(devpriv->las0 + LAS0_ADC) & FS_ADC_NOT_EMPTY) {
-               short sample;
-               s16 d = readw(devpriv->las1 + LAS1_ADC_FIFO);
+               unsigned short d = readw(devpriv->las1 + LAS1_ADC_FIFO);
 
                if (0 == devpriv->ai_count) {   /* done */
                        continue;       /* read rest */
@@ -686,13 +682,12 @@ static int ai_read_dregs(struct comedi_device *dev, struct comedi_subdevice *s)
 
                d = d >> 3;     /* low 3 bits are marker lines */
                if (CHAN_ARRAY_TEST(devpriv->chan_is_bipolar,
-                                   s->async->cur_chan)) {
+                                   s->async->cur_chan))
                        /* convert to comedi unsigned data */
-                       sample = d + 2048;
-               } else
-                       sample = d;
+                       d = comedi_offset_munge(s, d);
+               d &= s->maxdata;
 
-               if (!comedi_buf_put(s->async, sample))
+               if (!comedi_buf_put(s->async, d))
                        return -1;
 
                if (devpriv->ai_count > 0)      /* < 0, means read forever */