staging: comedi: dt282x: convert 'dabits' boardinfo to 'ao_maxdata'

This member of the boardinfo is the number of bits in the analog output data.
Convert this member into the subdevice 'maxdata', (1 << board->dabits) - 1,
to avoid needing to do the calculation.

Use the subdevice 'maxdata' in the driver instead of using the boardinfo and
use the comedi_offset_munge() helper to convert the two's complement data to
the offset binary form that the comedi core expects.

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>

diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index 523e8490fedc40a64150463310790edf8432590f..3eaf26cb2218386f97970283c8683738285482fd 100644 (file)
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -213,7 +213,7 @@ struct dt282x_board {
        int ai_speed;
        int ispgl;
        int dachan;
-       int dabits;
+       unsigned int ao_maxdata;
 };
 
 static const struct dt282x_board boardtypes[] = {
@@ -224,7 +224,7 @@ static const struct dt282x_board boardtypes[] = {
                .adchan_di      = 8,
                .ai_speed       = 20000,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2821-f",
                .ai_maxdata     = 0x0fff,
@@ -232,7 +232,7 @@ static const struct dt282x_board boardtypes[] = {
                .adchan_di      = 8,
                .ai_speed       = 6500,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2821-g",
                .ai_maxdata     = 0x0fff,
@@ -240,14 +240,14 @@ static const struct dt282x_board boardtypes[] = {
                .adchan_di      = 8,
                .ai_speed       = 4000,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2823",
                .ai_maxdata     = 0xffff,
                .adchan_di      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
-               .dabits         = 16,
+               .ao_maxdata     = 0xffff,
        }, {
                .name           = "dt2824-pgh",
                .ai_maxdata     = 0x0fff,
@@ -269,28 +269,28 @@ static const struct dt282x_board boardtypes[] = {
                .ai_speed       = 20000,
                .ispgl          = 1,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2827",
                .ai_maxdata     = 0xffff,
                .adchan_di      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2828",
                .ai_maxdata     = 0x0fff,
                .adchan_se      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt2829",
                .ai_maxdata     = 0xffff,
                .adchan_se      = 8,
                .ai_speed       = 33250,
                .dachan         = 2,
-               .dabits         = 16,
+               .ao_maxdata     = 0xffff,
        }, {
                .name           = "dt21-ez",
                .ai_maxdata     = 0x0fff,
@@ -298,7 +298,7 @@ static const struct dt282x_board boardtypes[] = {
                .adchan_di      = 8,
                .ai_speed       = 10000,
                .dachan         = 2,
-               .dabits         = 12,
+               .ao_maxdata     = 0x0fff,
        }, {
                .name           = "dt23-ez",
                .ai_maxdata     = 0xffff,
@@ -884,14 +884,13 @@ static int dt282x_ao_insn_write(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn, unsigned int *data)
 {
-       const struct dt282x_board *board = comedi_board(dev);
        struct dt282x_private *devpriv = dev->private;
-       unsigned short d;
+       unsigned int d;
        unsigned int chan;
 
        chan = CR_CHAN(insn->chanspec);
        d = data[0];
-       d &= (1 << board->dabits) - 1;
+       d &= s->maxdata;
        devpriv->ao[chan] = d;
 
        devpriv->dacsr |= DT2821_SSEL;
@@ -900,11 +899,11 @@ static int dt282x_ao_insn_write(struct comedi_device *dev,
                /* select channel */
                devpriv->dacsr |= DT2821_YSEL;
                if (devpriv->da0_2scomp)
-                       d ^= (1 << (board->dabits - 1));
+                       d = comedi_offset_munge(s, d);
        } else {
                devpriv->dacsr &= ~DT2821_YSEL;
                if (devpriv->da1_2scomp)
-                       d ^= (1 << (board->dabits - 1));
+                       d = comedi_offset_munge(s, d);
        }
 
        outw(devpriv->dacsr, dev->iobase + DT2821_DACSR);
@@ -1284,7 +1283,7 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
                s->subdev_flags = SDF_WRITABLE;
                s->insn_read = dt282x_ao_insn_read;
                s->insn_write = dt282x_ao_insn_write;
-               s->maxdata = (1 << board->dabits) - 1;
+               s->maxdata = board->ao_maxdata;
                s->range_table_list = devpriv->darangelist;
                devpriv->darangelist[0] =
                    opt_ao_range_lkup(it->options[opt_ao0_range]);