staging: comedi: dt282x: convert 'adbits' boardinfo to 'ai_maxdata'

This member of the boardinfo is the number of bits in the analog input data.
Convert this member into the subdevice 'maxdata', (1 << board->adbits) - 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 ea4abcc..523e849 100644 (file)
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -207,7 +207,7 @@ static const struct comedi_lrange range_dt282x_ai_hi_unipolar = {
 
 struct dt282x_board {
        const char *name;
-       int adbits;
+       unsigned int ai_maxdata;
        int adchan_se;
        int adchan_di;
        int ai_speed;
@@ -219,7 +219,7 @@ struct dt282x_board {
 static const struct dt282x_board boardtypes[] = {
        {
                .name           = "dt2821",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 20000,
@@ -227,7 +227,7 @@ static const struct dt282x_board boardtypes[] = {
                .dabits         = 12,
        }, {
                .name           = "dt2821-f",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 6500,
@@ -235,7 +235,7 @@ static const struct dt282x_board boardtypes[] = {
                .dabits         = 12,
        }, {
                .name           = "dt2821-g",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 4000,
@@ -243,27 +243,27 @@ static const struct dt282x_board boardtypes[] = {
                .dabits         = 12,
        }, {
                .name           = "dt2823",
-               .adbits         = 16,
+               .ai_maxdata     = 0xffff,
                .adchan_di      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
                .dabits         = 16,
        }, {
                .name           = "dt2824-pgh",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 20000,
        }, {
                .name           = "dt2824-pgl",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 20000,
                .ispgl          = 1,
        }, {
                .name           = "dt2825",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 20000,
@@ -272,28 +272,28 @@ static const struct dt282x_board boardtypes[] = {
                .dabits         = 12,
        }, {
                .name           = "dt2827",
-               .adbits         = 16,
+               .ai_maxdata     = 0xffff,
                .adchan_di      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
                .dabits         = 12,
        }, {
                .name           = "dt2828",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 4,
                .ai_speed       = 10000,
                .dachan         = 2,
                .dabits         = 12,
        }, {
                .name           = "dt2829",
-               .adbits         = 16,
+               .ai_maxdata     = 0xffff,
                .adchan_se      = 8,
                .ai_speed       = 33250,
                .dachan         = 2,
                .dabits         = 16,
        }, {
                .name           = "dt21-ez",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 10000,
@@ -301,19 +301,19 @@ static const struct dt282x_board boardtypes[] = {
                .dabits         = 12,
        }, {
                .name           = "dt23-ez",
-               .adbits         = 16,
+               .ai_maxdata     = 0xffff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 10000,
        }, {
                .name           = "dt24-ez",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 10000,
        }, {
                .name           = "dt24-ez-pgl",
-               .adbits         = 12,
+               .ai_maxdata     = 0x0fff,
                .adchan_se      = 16,
                .adchan_di      = 8,
                .ai_speed       = 10000,
@@ -449,26 +449,26 @@ static int dt282x_ns_to_timer(int *nanosec, int round_mode)
        return (15 << 8) | (255 - divider);
 }
 
-static void dt282x_munge(struct comedi_device *dev, unsigned short *buf,
+static void dt282x_munge(struct comedi_device *dev,
+                        struct comedi_subdevice *s,
+                        unsigned short *buf,
                         unsigned int nbytes)
 {
-       const struct dt282x_board *board = comedi_board(dev);
        struct dt282x_private *devpriv = dev->private;
-       unsigned int i;
-       unsigned short mask = (1 << board->adbits) - 1;
-       unsigned short sign = 1 << (board->adbits - 1);
-       int n;
-
-       if (devpriv->ad_2scomp)
-               sign = 1 << (board->adbits - 1);
-       else
-               sign = 0;
+       unsigned int val;
+       int i;
 
        if (nbytes % 2)
                comedi_error(dev, "bug! odd number of bytes from dma xfer");
-       n = nbytes / 2;
-       for (i = 0; i < n; i++)
-               buf[i] = (buf[i] & mask) ^ sign;
+
+       for (i = 0; i < nbytes / 2; i++) {
+               val = buf[i];
+               val &= s->maxdata;
+               if (devpriv->ad_2scomp)
+                       val = comedi_offset_munge(s, val);
+
+               buf[i] = val;
+       }
 }
 
 static void dt282x_ao_dma_interrupt(struct comedi_device *dev)
@@ -527,7 +527,7 @@ static void dt282x_ai_dma_interrupt(struct comedi_device *dev)
 
        devpriv->current_dma_index = 1 - i;
 
-       dt282x_munge(dev, ptr, size);
+       dt282x_munge(dev, s, ptr, size);
        ret = cfc_write_array_to_buffer(s, ptr, size);
        if (ret != size) {
                s->async->events |= COMEDI_CB_OVERFLOW;
@@ -597,10 +597,10 @@ static irqreturn_t dt282x_interrupt(int irq, void *d)
                unsigned short data;
 
                data = inw(dev->iobase + DT2821_ADDAT);
-               data &= (1 << board->adbits) - 1;
-
+               data &= s->maxdata;
                if (devpriv->ad_2scomp)
-                       data ^= 1 << (board->adbits - 1);
+                       data = comedi_offset_munge(s, data);
+
                ret = comedi_buf_put(s, data);
 
                if (ret == 0)
@@ -671,10 +671,11 @@ static int dt282x_ai_timeout(struct comedi_device *dev,
  */
 static int dt282x_ai_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
-                              struct comedi_insn *insn, unsigned int *data)
+                              struct comedi_insn *insn,
+                              unsigned int *data)
 {
-       const struct dt282x_board *board = comedi_board(dev);
        struct dt282x_private *devpriv = dev->private;
+       unsigned int val;
        int ret;
        int i;
 
@@ -698,11 +699,12 @@ static int dt282x_ai_insn_read(struct comedi_device *dev,
                if (ret)
                        return ret;
 
-               data[i] =
-                   inw(dev->iobase +
-                       DT2821_ADDAT) & ((1 << board->adbits) - 1);
+               val = inw(dev->iobase + DT2821_ADDAT);
+               val &= s->maxdata;
                if (devpriv->ad_2scomp)
-                       data[i] ^= (1 << (board->adbits - 1));
+                       val = comedi_offset_munge(s, val);
+
+               data[i] = val;
        }
 
        return i;
@@ -1260,7 +1262,7 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->n_chan =
            (it->options[opt_diff]) ? board->adchan_di : board->adchan_se;
        s->insn_read = dt282x_ai_insn_read;
-       s->maxdata = (1 << board->adbits) - 1;
+       s->maxdata = board->ai_maxdata;
        s->range_table =
            opt_ai_range_lkup(board->ispgl, it->options[opt_ai_range]);
        devpriv->ad_2scomp = it->options[opt_ai_twos];