staging: comedi: usbduxsigma: tidy up usbdux_ai_insn_read()

Rename the function so it has namespace associated with the driver.
Rename the local variable used for the private data pointer.

Return -EBUSY if an asynchronous command is running and the read cannot
be completed.

Propagate the errno if the receive_dux_command() fails.

Tidy up the function to make it more concise.

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/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
index 28b4b7a6031f2fcbafb14469c542546c24283339..ce2e40f258c2b180d39c85de1fc5d20db7f35a0d 100644 (file)
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -791,67 +791,61 @@ static int usbdux_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        return 0;
 }
 
-/* Mode 0 is used to get a single conversion on demand */
-static int usbdux_ai_insn_read(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn, unsigned int *data)
+static int usbduxsigma_ai_insn_read(struct comedi_device *dev,
+                                   struct comedi_subdevice *s,
+                                   struct comedi_insn *insn,
+                                   unsigned int *data)
 {
-       struct usbduxsigma_private *this_usbduxsub = dev->private;
-       int i;
-       int32_t one = 0;
-       int chan;
-       int err;
+       struct usbduxsigma_private *devpriv = dev->private;
+       unsigned int chan = CR_CHAN(insn->chanspec);
        uint8_t muxsg0 = 0;
        uint8_t muxsg1 = 0;
        uint8_t sysred = 0;
+       int ret;
+       int i;
 
-       down(&this_usbduxsub->sem);
-       if (this_usbduxsub->ai_cmd_running) {
-               up(&this_usbduxsub->sem);
-               return 0;
+       down(&devpriv->sem);
+       if (devpriv->ai_cmd_running) {
+               up(&devpriv->sem);
+               return -EBUSY;
        }
 
-       /* sample one channel */
-       /* CONFIG0: chopper on */
-       this_usbduxsub->dux_commands[1] = 0x16;
-
-       /* CONFIG1: 2kHz sampling rate */
-       this_usbduxsub->dux_commands[2] = 0x80;
-
-       /* CONFIG3: differential channels off */
-       this_usbduxsub->dux_commands[3] = 0x00;
-
-       chan = CR_CHAN(insn->chanspec);
        create_adc_command(chan, &muxsg0, &muxsg1);
 
-       this_usbduxsub->dux_commands[4] = muxsg0;
-       this_usbduxsub->dux_commands[5] = muxsg1;
-       this_usbduxsub->dux_commands[6] = sysred;
+       /* Mode 0 is used to get a single conversion on demand */
+       devpriv->dux_commands[1] = 0x16; /* CONFIG0: chopper on */
+       devpriv->dux_commands[2] = 0x80; /* CONFIG1: 2kHz sampling rate */
+       devpriv->dux_commands[3] = 0x00; /* CONFIG3: diff. channels off */
+       devpriv->dux_commands[4] = muxsg0;
+       devpriv->dux_commands[5] = muxsg1;
+       devpriv->dux_commands[6] = sysred;
 
        /* adc commands */
-       err = send_dux_commands(dev, SENDSINGLEAD);
-       if (err < 0) {
-               up(&this_usbduxsub->sem);
-               return err;
+       ret = send_dux_commands(dev, SENDSINGLEAD);
+       if (ret < 0) {
+               up(&devpriv->sem);
+               return ret;
        }
 
        for (i = 0; i < insn->n; i++) {
-               err = receive_dux_commands(dev, SENDSINGLEAD);
-               if (err < 0) {
-                       up(&this_usbduxsub->sem);
-                       return 0;
+               int32_t val;
+
+               ret = receive_dux_commands(dev, SENDSINGLEAD);
+               if (ret < 0) {
+                       up(&devpriv->sem);
+                       return ret;
                }
+
                /* 32 bits big endian from the A/D converter */
-               one = be32_to_cpu(*((int32_t *)
-                                   ((this_usbduxsub->insnBuffer)+1)));
-               /* mask out the status byte */
-               one = one & 0x00ffffff;
-               /* turn it into an unsigned integer */
-               one = one ^ 0x00800000;
-               data[i] = one;
+               val = be32_to_cpu(*((int32_t *)((devpriv->insnBuffer) + 1)));
+               val &= 0x00ffffff;      /* strip status byte */
+               val ^= 0x00800000;      /* convert to unsigned */
+
+               data[i] = val;
        }
-       up(&this_usbduxsub->sem);
-       return i;
+       up(&devpriv->sem);
+
+       return insn->n;
 }
 
 static int usbduxsigma_ao_insn_read(struct comedi_device *dev,
@@ -1453,7 +1447,7 @@ static int usbduxsigma_attach_common(struct comedi_device *dev)
        s->len_chanlist = NUMCHANNELS;
        s->maxdata      = 0x00ffffff;
        s->range_table  = &range_usbdux_ai_range;
-       s->insn_read    = usbdux_ai_insn_read;
+       s->insn_read    = usbduxsigma_ai_insn_read;
        s->do_cmdtest   = usbdux_ai_cmdtest;
        s->do_cmd       = usbdux_ai_cmd;
        s->cancel       = usbdux_ai_cancel;