staging: comedi: adl_pci9111: cleanup ai read in pci9111_ai_insn_read()

The shift, maxdata, and invert values, used to handle the 12-/16-bit
analog input differences, can be calculated based on the subdevice
maxdata value.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/adl_pci9111.c b/drivers/staging/comedi/drivers/adl_pci9111.c
index b009c7b..0093a40 100644 (file)
--- a/drivers/staging/comedi/drivers/adl_pci9111.c
+++ b/drivers/staging/comedi/drivers/adl_pci9111.c
@@ -966,10 +966,11 @@ static int pci9111_ai_insn_read(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn, unsigned int *data)
 {
-       int resolution =
-           ((struct pci9111_board *)dev->board_ptr)->ai_resolution;
-
-       int timeout, i;
+       unsigned int maxdata = s->maxdata;
+       unsigned int invert = (maxdata + 1) >> 1;
+       unsigned int shift = (maxdata == 0xffff) ? 0 : 4;
+       int timeout;
+       int i;
 
        pci9111_ai_channel_set(CR_CHAN((&insn->chanspec)[0]));
 
@@ -995,14 +996,8 @@ static int pci9111_ai_insn_read(struct comedi_device *dev,
 
 conversion_done:
 
-               if (resolution == PCI9111_HR_AI_RESOLUTION)
-                       data[i] = (inw(dev->iobase + PCI9111_AI_FIFO_REG)
-                                       & PCI9111_HR_AI_RESOLUTION_MASK)
-                                       ^ PCI9111_HR_AI_RESOLUTION_2_CMP_BIT;
-               else
-                       data[i] = ((inw(dev->iobase + PCI9111_AI_FIFO_REG) >> 4)
-                                       & PCI9111_AI_RESOLUTION_MASK)
-                                       ^ PCI9111_AI_RESOLUTION_2_CMP_BIT;
+               data[i] = inw(dev->iobase + PCI9111_AI_FIFO_REG);
+               data[i] = ((data[i] >> shift) & maxdata) ^ invert;
        }
 
        return i;