staging: comedi: dt9812: cleanup analog out subdevice (*insn_write)

For aesthetic reasons, rename the function to help with grepping and
rename some of the local vars.

The dt9812_analog_out() function can fail. Make sure to check for any
failure and return the errno.

The comedi core expects the (*insn_write) functions to return either
an errno or the number of samples written. Change the final return to
insn->n to make this clearer.

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/dt9812.c b/drivers/staging/comedi/drivers/dt9812.c
index c1f6a5e..3a187cc 100644 (file)
--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -656,16 +656,22 @@ static int dt9812_ao_insn_read(struct comedi_device *dev,
        return insn->n;
 }
 
-static int dt9812_ao_winsn(struct comedi_device *dev,
-                          struct comedi_subdevice *s, struct comedi_insn *insn,
-                          unsigned int *data)
+static int dt9812_ao_insn_write(struct comedi_device *dev,
+                               struct comedi_subdevice *s,
+                               struct comedi_insn *insn,
+                               unsigned int *data)
 {
-       unsigned int channel = CR_CHAN(insn->chanspec);
-       int n;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       int ret;
+       int i;
 
-       for (n = 0; n < insn->n; n++)
-               dt9812_analog_out(dev, channel, data[n]);
-       return n;
+       for (i = 0; i < insn->n; i++) {
+               ret = dt9812_analog_out(dev, chan, data[i]);
+               if (ret)
+                       return ret;
+       }
+
+       return insn->n;
 }
 
 static int dt9812_find_endpoints(struct comedi_device *dev)
@@ -847,7 +853,7 @@ static int dt9812_auto_attach(struct comedi_device *dev,
        s->n_chan       = 2;
        s->maxdata      = 0x0fff;
        s->range_table  = is_unipolar ? &range_unipolar2_5 : &range_bipolar10;
-       s->insn_write   = dt9812_ao_winsn;
+       s->insn_write   = dt9812_ao_insn_write;
        s->insn_read    = dt9812_ao_insn_read;
 
        devpriv->ao_shadow[0] = is_unipolar ? 0x0000 : 0x0800;