staging: comedi: me_daq: cleanup me_dio_insn_bits()

This function only needs to update the output channel state when
the 'mask' (data[0]) indicates that the state is changing. It's
also supposed to return the state for all the input and output
channels in data[1].

This function appears to work correctly but it's coded quite
differently form the other comedi drivers. Rework the function so
it follows the normal form. Also, use a couple local variables
for the mmio addresses used to read/write the dio ports.

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/me_daq.c b/drivers/staging/comedi/drivers/me_daq.c
index 450bee0..823fbf9 100644 (file)
--- a/drivers/staging/comedi/drivers/me_daq.c
+++ b/drivers/staging/comedi/drivers/me_daq.c
@@ -229,33 +229,40 @@ static int me_dio_insn_config(struct comedi_device *dev,
        return insn->n;
 }
 
-/* Digital instant input/outputs */
 static int me_dio_insn_bits(struct comedi_device *dev,
                            struct comedi_subdevice *s,
-                           struct comedi_insn *insn, unsigned int *data)
+                           struct comedi_insn *insn,
+                           unsigned int *data)
 {
        struct me_private_data *dev_private = dev->private;
+       void __iomem *mmio_porta = dev_private->me_regbase + ME_DIO_PORT_A;
+       void __iomem *mmio_portb = dev_private->me_regbase + ME_DIO_PORT_B;
        unsigned int mask = data[0];
+       unsigned int bits = data[1];
+       unsigned int val;
+
+       mask &= s->io_bits;     /* only update the COMEDI_OUTPUT channels */
+       if (mask) {
+               s->state &= ~mask;
+               s->state |= (bits & mask);
+
+               if (mask & 0x0000ffff)
+                       writew((s->state & 0xffff), mmio_porta);
+               if (mask & 0xffff0000)
+                       writew(((s->state >> 16) & 0xffff), mmio_portb);
+       }
 
-       s->state &= ~mask;
-       s->state |= (mask & data[1]);
+       if (s->io_bits & 0x0000ffff)
+               val = s->state & 0xffff;
+       else
+               val = readw(mmio_porta);
 
-       mask &= s->io_bits;
-       if (mask & 0x0000ffff) {        /* Port A */
-               writew((s->state & 0xffff),
-                      dev_private->me_regbase + ME_DIO_PORT_A);
-       } else {
-               data[1] &= ~0x0000ffff;
-               data[1] |= readw(dev_private->me_regbase + ME_DIO_PORT_A);
-       }
+       if (s->io_bits & 0xffff0000)
+               val |= (s->state & 0xffff0000);
+       else
+               val |= (readw(mmio_portb) << 16);
 
-       if (mask & 0xffff0000) {        /* Port B */
-               writew(((s->state >> 16) & 0xffff),
-                      dev_private->me_regbase + ME_DIO_PORT_B);
-       } else {
-               data[1] &= ~0xffff0000;
-               data[1] |= readw(dev_private->me_regbase + ME_DIO_PORT_B) << 16;
-       }
+       data[1] = val;
 
        return insn->n;
 }