staging: comedi: pcmuio: cleanup DIO subdevice (*insn_{bits,config})

Use the pcmuio_{read,write}() helpers to read/write all 24 channels
instead of handling the digital I/O as three separate ports. This
simplifies both functions with minimal overhead.

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/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c
index e52f6aeee45376f457b93b6f80aa7f219606e20c..d1f5fc0240897d91bab774d9a2f93c5f0f5be2a2 100644 (file)
--- a/drivers/staging/comedi/drivers/pcmuio.c
+++ b/drivers/staging/comedi/drivers/pcmuio.c
@@ -203,51 +203,42 @@ static unsigned int pcmuio_read(struct comedi_device *dev,
        return val;
 }
 
+/*
+ * Each channel can be individually programmed for input or output.
+ * Writing a '0' to a channel causes the corresponding output pin
+ * to go to a high-z state (pulled high by an external 10K resistor).
+ * This allows it to be used as an input. When used in the input mode,
+ * a read reflects the inverted state of the I/O pin, such that a
+ * high on the pin will read as a '0' in the register. Writing a '1'
+ * to a bit position causes the pin to sink current (up to 12mA),
+ * effectively pulling it low.
+ */
 static int pcmuio_dio_insn_bits(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_insn *insn, unsigned int *data)
 {
+       unsigned int mask = data[0] & s->io_bits;       /* outputs only */
+       unsigned int bits = data[1];
        int asic = s->index / 2;
        int port = (s->index % 2) ? 3 : 0;
-       unsigned long iobase = dev->iobase + (asic * ASIC_IOSIZE);
-       int byte_no;
-
-       /* NOTE:
-          reading a 0 means this channel was high
-          writine a 0 sets the channel high
-          reading a 1 means this channel was low
-          writing a 1 means set this channel low
-
-          Therefore everything is always inverted. */
-
-       /* The insn data is a mask in data[0] and the new data
-        * in data[1], each channel cooresponding to a bit. */
+       unsigned int val;
 
-       s->state = 0;
+       /* get inverted state of the channels from the port */
+       val = pcmuio_read(dev, asic, 0, port);
 
-       for (byte_no = 0; byte_no < s->n_chan / CHANS_PER_PORT; ++byte_no) {
-               /* bit offset of port in 32-bit doubleword */
-               unsigned long offset = byte_no * 8;
-               /* this 8-bit port's data */
-               unsigned char byte = 0,
-                   /* The write mask for this port (if any) */
-                   write_mask_byte = (data[0] >> offset) & 0xff,
-                   /* The data byte for this port */
-                   data_byte = (data[1] >> offset) & 0xff;
+       /* get the true state of the channels */
+       s->state = val ^ ((0x1 << s->n_chan) - 1);
 
-               byte = inb(iobase + PCMUIO_PORT_REG(port + byte_no));
+       if (mask) {
+               s->state &= ~mask;
+               s->state |= (mask & bits);
 
-               if (write_mask_byte) {
-                       byte &= ~write_mask_byte;
-                       byte |= ~data_byte & write_mask_byte;
-                       outb(byte, iobase + PCMUIO_PORT_REG(port + byte_no));
-               }
-               /* save the digital input lines for this byte.. */
-               s->state |= ((unsigned int)byte) << offset;
+               /* invert the state and update the channels */
+               val = s->state ^ ((0x1 << s->n_chan) - 1);
+               pcmuio_write(dev, val, asic, 0, port);
        }
 
-       /* now return the DIO lines to data[1] - note they came inverted! */
-       data[1] = ~s->state;
+       data[1] = s->state;
 
        return insn->n;
 }
@@ -256,58 +247,21 @@ static int pcmuio_dio_insn_config(struct comedi_device *dev,
                                  struct comedi_subdevice *s,
                                  struct comedi_insn *insn, unsigned int *data)
 {
+       unsigned int chan_mask = 1 << CR_CHAN(insn->chanspec);
        int asic = s->index / 2;
        int port = (s->index % 2) ? 3 : 0;
-       unsigned long iobase = dev->iobase + (asic * ASIC_IOSIZE);
-       unsigned int chan = CR_CHAN(insn->chanspec);
-       int byte_no = chan / 8;
-       int bit_no = chan % 8;
-       unsigned char byte;
-
-       /* NOTE:
-          writing a 0 an IO channel's bit sets the channel to INPUT
-          and pulls the line high as well
-
-          writing a 1 to an IO channel's  bit pulls the line low
-
-          All channels are implicitly always in OUTPUT mode -- but when
-          they are high they can be considered to be in INPUT mode..
-
-          Thus, we only force channels low if the config request was INPUT,
-          otherwise we do nothing to the hardware.    */
 
        switch (data[0]) {
        case INSN_CONFIG_DIO_OUTPUT:
-               /* save to io_bits -- don't actually do anything since
-                  all input channels are also output channels... */
-               s->io_bits |= 1 << chan;
+               s->io_bits |= chan_mask;
                break;
        case INSN_CONFIG_DIO_INPUT:
-               /* write a 0 to the actual register representing the channel
-                  to set it to 'input'.  0 means "float high". */
-               byte = inb(iobase + PCMUIO_PORT_REG(port + byte_no));
-               byte &= ~(1 << bit_no);
-                               /**< set input channel to '0' */
-
-               /*
-                * write out byte
-                * This is the only time we actually affect the hardware
-                * as all channels are implicitly output -- but input
-                * channels are set to float-high.
-                */
-               outb(byte, iobase + PCMUIO_PORT_REG(port + byte_no));
-
-               /* save to io_bits */
-               s->io_bits &= ~(1 << chan);
+               s->io_bits &= ~chan_mask;
+               pcmuio_write(dev, s->io_bits, asic, 0, port);
                break;
-
        case INSN_CONFIG_DIO_QUERY:
-               /* retrieve from shadow register */
-               data[1] =
-                   (s->io_bits & (1 << chan)) ? COMEDI_OUTPUT : COMEDI_INPUT;
-               return insn->n;
+               data[1] = (s->io_bits & chan_mask) ? COMEDI_OUTPUT : COMEDI_INPUT;
                break;
-
        default:
                return -EINVAL;
                break;