staging: comedi: addi_apci_3501: introduce apci3501_wait_for_dac()

Refactor the code that waits for the DAC to be ready into a helper
function.

A timeout of some sort should be added to this helper so code the
users to expect the error condition. In i_APCI3501_WriteAnalogOutput()
just return the error and don't actually write the new value to the
DAC. In apci3501_reset() output a dev_warn() that the DAC was not
ready.

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/addi-data/hwdrv_apci3501.c b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3501.c
index 9739e8b..b057906 100644 (file)
--- a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3501.c
+++ b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3501.c
@@ -136,7 +136,8 @@ static int i_APCI3501_WriteAnalogOutput(struct comedi_device *dev,
                                        unsigned int *data)
 {
        struct apci3501_private *devpriv = dev->private;
-       unsigned int ul_Command1 = 0, ul_Channel_no, ul_Polarity, ul_DAC_Ready = 0;
+       unsigned int ul_Command1 = 0, ul_Channel_no, ul_Polarity;
+       int ret;
 
        ul_Channel_no = CR_CHAN(insn->chanspec);
 
@@ -159,21 +160,15 @@ static int i_APCI3501_WriteAnalogOutput(struct comedi_device *dev,
                printk("\nIn WriteAnalogOutput :: Not Valid Channel\n");
        }                       /*  end if((ul_Channel_no<0)||(ul_Channel_no>7)) */
 
-       ul_DAC_Ready = inl(dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
+       ret = apci3501_wait_for_dac(dev);
+       if (ret)
+               return ret;
 
-       while (ul_DAC_Ready == 0) {
-               ul_DAC_Ready = inl(dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
-               ul_DAC_Ready = (ul_DAC_Ready >> 8) & 1;
-       }
-
-       if (ul_DAC_Ready) {
-/* Output the Value on the output channels. */
-               ul_Command1 =
-                       (unsigned int) ((unsigned int) (ul_Channel_no & 0xFF) |
+       /* Output the Value on the output channels. */
+       ul_Command1 = (unsigned int) ((unsigned int) (ul_Channel_no & 0xFF) |
                        (unsigned int) ((*data << 0x8) & 0x7FFFFF00L) |
                        (unsigned int) (ul_Polarity));
-               outl(ul_Command1, dev->iobase + APCI3501_AO_DATA_REG);
-       }
+       outl(ul_Command1, dev->iobase + APCI3501_AO_DATA_REG);
 
        return insn->n;
 }

diff --git a/drivers/staging/comedi/drivers/addi_apci_3501.c b/drivers/staging/comedi/drivers/addi_apci_3501.c
index b4679b2..906c37a 100644 (file)
--- a/drivers/staging/comedi/drivers/addi_apci_3501.c
+++ b/drivers/staging/comedi/drivers/addi_apci_3501.c
@@ -47,6 +47,17 @@ static struct comedi_lrange apci3501_ao_range = {
        }
 };
 
+static int apci3501_wait_for_dac(struct comedi_device *dev)
+{
+       unsigned int status;
+
+       do {
+               status = inl(dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
+       } while (!(status & APCI3501_AO_STATUS_READY));
+
+       return 0;
+}
+
 #include "addi-data/hwdrv_apci3501.c"
 
 static int apci3501_di_insn_bits(struct comedi_device *dev,
@@ -209,7 +220,8 @@ static irqreturn_t apci3501_interrupt(int irq, void *d)
 static int apci3501_reset(struct comedi_device *dev)
 {
        int i_Count = 0, i_temp = 0;
-       unsigned int ul_Command1 = 0, ul_Polarity, ul_DAC_Ready = 0;
+       unsigned int ul_Command1 = 0, ul_Polarity;
+       int ret;
 
        outl(0x0, dev->iobase + APCI3501_DO_REG);
        outl(1, dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
@@ -217,15 +229,12 @@ static int apci3501_reset(struct comedi_device *dev)
        ul_Polarity = 0x80000000;
 
        for (i_Count = 0; i_Count <= 7; i_Count++) {
-               ul_DAC_Ready = inl(dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
-
-               while (ul_DAC_Ready == 0) {
-                       ul_DAC_Ready =
-                               inl(dev->iobase + APCI3501_AO_CTRL_STATUS_REG);
-                       ul_DAC_Ready = (ul_DAC_Ready >> 8) & 1;
-               }
-
-               if (ul_DAC_Ready) {
+               ret = apci3501_wait_for_dac(dev);
+               if (ret) {
+                       dev_warn(dev->class_dev,
+                                "%s: DAC not-ready for channel %i\n",
+                                __func__, i_Count);
+               } else {
                        /*  Output the Value on the output channels. */
                        ul_Command1 =
                                (unsigned int) ((unsigned int) (i_Count & 0xFF) |