staging: comedi: pcmad: return errno if AI conversion times out

Instead of returning invalid data, return -ETIME if the analog input
conversion times out.

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/pcmad.c b/drivers/staging/comedi/drivers/pcmad.c
index 79cc2e6304649aa7f340b45fd6df1f58636162d9..f64e75b871a75fcd7791aedf8004b772496a4f24 100644 (file)
--- a/drivers/staging/comedi/drivers/pcmad.c
+++ b/drivers/staging/comedi/drivers/pcmad.c
@@ -72,25 +72,37 @@ struct pcmad_priv_struct {
 
 #define TIMEOUT        100
 
+static int pcmad_ai_wait_for_eoc(struct comedi_device *dev,
+                                int timeout)
+{
+       int i;
+
+       for (i = 0; i < timeout; i++) {
+               if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)
+                       return 0;
+       }
+       return -ETIME;
+}
+
 static int pcmad_ai_insn_read(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_insn *insn, unsigned int *data)
 {
        const struct pcmad_board_struct *board = comedi_board(dev);
        struct pcmad_priv_struct *devpriv = dev->private;
-       int i;
        int chan;
        int n;
+       int ret;
 
        chan = CR_CHAN(insn->chanspec);
 
        for (n = 0; n < insn->n; n++) {
                outb(chan, dev->iobase + PCMAD_CONVERT);
 
-               for (i = 0; i < TIMEOUT; i++) {
-                       if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)
-                               break;
-               }
+               ret = pcmad_ai_wait_for_eoc(dev, TIMEOUT);
+               if (ret)
+                       return ret;
+
                data[n] = inb(dev->iobase + PCMAD_LSB);
                data[n] |= (inb(dev->iobase + PCMAD_MSB) << 8);