staging: comedi: dt282x: fix dt282x_ao_insn_read()
authorH Hartley Sweeten <hsweeten@visionengravers.com>
Fri, 20 Jun 2014 20:12:50 +0000 (13:12 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 27 Jun 2014 00:08:19 +0000 (20:08 -0400)
The comedi core expects the (*insn_read) functions to return 'insn->n'
samples. Fix this function to work like the core expects.

For aesthetics, rename the private data 'ao' member to clarify its
use. Also, remove the unnecessary comment.

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>
drivers/staging/comedi/drivers/dt282x.c

index d4164ce..f248dbc 100644 (file)
@@ -326,7 +326,7 @@ struct dt282x_private {
 
        const struct comedi_lrange *darangelist[2];
 
-       unsigned short ao[2];
+       unsigned short ao_readback[2];
 
        int dacsr;      /* software copies of registers */
        int adcsr;
@@ -828,21 +828,19 @@ static int dt282x_ai_cancel(struct comedi_device *dev,
        return 0;
 }
 
-/*
- *    Analog output routine.  Selects single channel conversion,
- *      selects correct channel, converts from 2's compliment to
- *      offset binary if necessary, loads the data into the DAC
- *      data register, and performs the conversion.
- */
 static int dt282x_ao_insn_read(struct comedi_device *dev,
                               struct comedi_subdevice *s,
-                              struct comedi_insn *insn, unsigned int *data)
+                              struct comedi_insn *insn,
+                              unsigned int *data)
 {
        struct dt282x_private *devpriv = dev->private;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       int i;
 
-       data[0] = devpriv->ao[CR_CHAN(insn->chanspec)];
+       for (i = 0; i < insn->n; i++)
+               data[i] = devpriv->ao_readback[chan];
 
-       return 1;
+       return insn->n;
 }
 
 static int dt282x_ao_insn_write(struct comedi_device *dev,
@@ -869,7 +867,7 @@ static int dt282x_ao_insn_write(struct comedi_device *dev,
 
        for (i = 0; i < insn->n; i++) {
                val = data[i];
-               devpriv->ao[chan] = val;
+               devpriv->ao_readback[chan] = val;
 
                if (munge)
                        val = comedi_offset_munge(s, val);