[PATCH 09/13] staging: comedi: cb_pcidas: use comedi_async 'scans_done' to detect AO EOA

[H Hartley Sweeten]

Remove the private data member 'ao_count' and use the comedi_async 'scans_done'
member to detect the analog output end-of-acquisition.

Use the comedi_nsamples_left() helper to get the number of samples to actually
read from the async buffer.

Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/staging/comedi/drivers/cb_pcidas.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/staging/comedi/drivers/cb_pcidas.c 
b/drivers/staging/comedi/drivers/cb_pcidas.c
index e211ef8..10c67fe 100644
--- a/drivers/staging/comedi/drivers/cb_pcidas.c
+++ b/drivers/staging/comedi/drivers/cb_pcidas.c
@@ -356,8 +356,6 @@ struct cb_pcidas_private {
        /* divisors of master clock for analog output pacing */
        unsigned int ao_divisor1;
        unsigned int ao_divisor2;
-       /* number of analog output samples remaining */
-       unsigned int ao_count;
        unsigned int caldac_value[NUM_CHANNELS_8800];
        unsigned int trimpot_value[NUM_CHANNELS_8402];
        unsigned int dac08_value;
@@ -1134,17 +1132,12 @@ static void cb_pcidas_ao_load_fifo(struct comedi_device 
*dev,
                                   unsigned int nsamples)
 {
        struct cb_pcidas_private *devpriv = dev->private;
-       struct comedi_cmd *cmd = &s->async->cmd;
        unsigned int nbytes;
 
-       if (cmd->stop_src == TRIG_COUNT && devpriv->ao_count < nsamples)
-               nsamples = devpriv->ao_count;
-
+       nsamples = comedi_nsamples_left(s, nsamples);
        nbytes = comedi_buf_read_samples(s, devpriv->ao_buffer, nsamples);
-       nsamples = comedi_bytes_to_samples(s, nbytes);
-       if (cmd->stop_src == TRIG_COUNT)
-               devpriv->ao_count -= nsamples;
 
+       nsamples = comedi_bytes_to_samples(s, nbytes);
        outsw(devpriv->ao_registers + DACDATA, devpriv->ao_buffer, nsamples);
 }
 
@@ -1226,9 +1219,6 @@ static int cb_pcidas_ao_cmd(struct comedi_device *dev,
        if (cmd->scan_begin_src == TRIG_TIMER)
                cb_pcidas_ao_load_counters(dev);
 
-       /*  set number of conversions */
-       if (cmd->stop_src == TRIG_COUNT)
-               devpriv->ao_count = cmd->chanlist_len * cmd->stop_arg;
        /*  set pacer source */
        spin_lock_irqsave(&dev->spinlock, flags);
        switch (cmd->scan_begin_src) {
@@ -1286,13 +1276,13 @@ static void handle_ao_interrupt(struct comedi_device 
*dev, unsigned int status)
                     devpriv->control_status + INT_ADCFIFO);
                spin_unlock_irqrestore(&dev->spinlock, flags);
                if (inw(devpriv->ao_registers + DAC_CSR) & DAC_EMPTY) {
-                       if (cmd->stop_src == TRIG_NONE ||
-                           (cmd->stop_src == TRIG_COUNT
-                            && devpriv->ao_count)) {
+                       if (cmd->stop_src == TRIG_COUNT &&
+                           async->scans_done >= cmd->stop_arg) {
+                               async->events |= COMEDI_CB_EOA;
+                       } else {
                                dev_err(dev->class_dev, "dac fifo underflow\n");
                                async->events |= COMEDI_CB_ERROR;
                        }
-                       async->events |= COMEDI_CB_EOA;
                }
        } else if (status & DAHFI) {
                cb_pcidas_ao_load_fifo(dev, s, thisboard->fifo_size / 2);
-- 
2.0.3

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