staging: comedi: ni_labpc: introduce labpc_ai_wait_for_data()

Introduce a helper function to wait for the a/d conversion to
complete.

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/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c
index 9e47fc0322f4f6f77473605421edf2b9ece02559..ceb6e786cbdd7bd705644f5dc8a0ff1121c4e07e 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_labpc.c
+++ b/drivers/staging/comedi/drivers/ni_labpc.c
@@ -206,6 +206,8 @@ NI manuals:
 #define   INIT_A1_BITS 0x70
 #define COUNTER_B_BASE_REG     0x18
 
+#define LABPC_ADC_TIMEOUT      1000
+
 enum scan_mode {
        MODE_SINGLE_CHAN,
        MODE_SINGLE_CHAN_INTERVAL,
@@ -453,6 +455,21 @@ static void labpc_clear_adc_fifo(struct comedi_device *dev)
        labpc_read_adc_fifo(dev);
 }
 
+static int labpc_ai_wait_for_data(struct comedi_device *dev,
+                                 int timeout)
+{
+       struct labpc_private *devpriv = dev->private;
+       int i;
+
+       for (i = 0; i < timeout; i++) {
+               devpriv->stat1 = devpriv->read_byte(dev->iobase + STATUS1_REG);
+               if (devpriv->stat1 & DATA_AVAIL_BIT)
+                       return 0;
+               udelay(1);
+       }
+       return -ETIME;
+}
+
 static int labpc_ai_insn_read(struct comedi_device *dev,
                              struct comedi_subdevice *s,
                              struct comedi_insn *insn,
@@ -462,8 +479,8 @@ static int labpc_ai_insn_read(struct comedi_device *dev,
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
        unsigned int aref = CR_AREF(insn->chanspec);
-       int timeout = 1000;
-       int i, n;
+       int ret;
+       int i;
 
        /* disable timed conversions, interrupt generation and dma */
        labpc_cancel(dev, s);
@@ -489,24 +506,18 @@ static int labpc_ai_insn_read(struct comedi_device *dev,
 
        labpc_clear_adc_fifo(dev);
 
-       for (n = 0; n < insn->n; n++) {
+       for (i = 0; i < insn->n; i++) {
                /* trigger conversion */
                devpriv->write_byte(0x1, dev->iobase + ADC_CONVERT_REG);
 
-               for (i = 0; i < timeout; i++) {
-                       if (devpriv->read_byte(dev->iobase +
-                                              STATUS1_REG) & DATA_AVAIL_BIT)
-                               break;
-                       udelay(1);
-               }
-               if (i == timeout) {
-                       comedi_error(dev, "timeout");
-                       return -ETIME;
-               }
-               data[n] = labpc_read_adc_fifo(dev);
+               ret = labpc_ai_wait_for_data(dev, LABPC_ADC_TIMEOUT);
+               if (ret)
+                       return ret;
+
+               data[i] = labpc_read_adc_fifo(dev);
        }
 
-       return n;
+       return insn->n;
 }
 
 #ifdef CONFIG_ISA_DMA_API