staging: comedi: addi_apci_2032: support stop_src == TRIG_COUNT

When setting up asynchronous commands on the special interrupt
subdevice, support the `TRIG_COUNT` stop source to allow the command to
stop automatically after a specified number of scans.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/addi_apci_2032.c b/drivers/staging/comedi/drivers/addi_apci_2032.c
index c302bf9..31e1259 100644 (file)
--- a/drivers/staging/comedi/drivers/addi_apci_2032.c
+++ b/drivers/staging/comedi/drivers/addi_apci_2032.c
@@ -60,6 +60,7 @@ struct apci2032_private {
 
 struct apci2032_int_private {
        spinlock_t spinlock;
+       unsigned int stop_count;
        bool active;
        unsigned char enabled_isns;
 };
@@ -179,6 +180,30 @@ static void apci2032_int_stop(struct comedi_device *dev,
        outl(0x0, dev->iobase + APCI2032_INT_CTRL_REG);
 }
 
+static bool apci2032_int_start(struct comedi_device *dev,
+                              struct comedi_subdevice *s,
+                              unsigned char enabled_isns)
+{
+       struct apci2032_int_private *subpriv = s->private;
+       struct comedi_cmd *cmd = &s->async->cmd;
+       bool do_event;
+
+       subpriv->enabled_isns = enabled_isns;
+       subpriv->stop_count = cmd->stop_arg;
+       if (cmd->stop_src == TRIG_COUNT && subpriv->stop_count == 0) {
+               /* An empty acquisition! */
+               s->async->events |= COMEDI_CB_EOA;
+               subpriv->active = false;
+               do_event = true;
+       } else {
+               subpriv->active = true;
+               outl(enabled_isns, dev->iobase + APCI2032_INT_CTRL_REG);
+               do_event = false;
+       }
+
+       return do_event;
+}
+
 static int apci2032_int_cmdtest(struct comedi_device *dev,
                                struct comedi_subdevice *s,
                                struct comedi_cmd *cmd)
@@ -191,12 +216,14 @@ static int apci2032_int_cmdtest(struct comedi_device *dev,
        err |= cfc_check_trigger_src(&cmd->scan_begin_src, TRIG_EXT);
        err |= cfc_check_trigger_src(&cmd->convert_src, TRIG_NOW);
        err |= cfc_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
-       err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_NONE);
+       err |= cfc_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
 
        if (err)
                return 1;
 
        /* Step 2a : make sure trigger sources are unique */
+       err |= cfc_check_trigger_is_unique(cmd->stop_src);
+
        /* Step 2b : and mutually compatible */
 
        if (err)
@@ -208,7 +235,8 @@ static int apci2032_int_cmdtest(struct comedi_device *dev,
        err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
        err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
        err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
-       err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
+       if (cmd->stop_src == TRIG_NONE)
+               err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
        if (err)
                return 3;
@@ -229,17 +257,19 @@ static int apci2032_int_cmd(struct comedi_device *dev,
        unsigned char enabled_isns;
        unsigned int n;
        unsigned long flags;
+       bool do_event;
 
        enabled_isns = 0;
        for (n = 0; n < cmd->chanlist_len; n++)
                enabled_isns |= 1 << CR_CHAN(cmd->chanlist[n]);
 
        spin_lock_irqsave(&subpriv->spinlock, flags);
-       subpriv->enabled_isns = enabled_isns;
-       subpriv->active = true;
-       outl(subpriv->enabled_isns, dev->iobase + APCI2032_INT_CTRL_REG);
+       do_event = apci2032_int_start(dev, s, enabled_isns);
        spin_unlock_irqrestore(&subpriv->spinlock, flags);
 
+       if (do_event)
+               comedi_event(dev, s);
+
        return 0;
 }
 
@@ -300,6 +330,15 @@ static irqreturn_t apci2032_interrupt(int irq, void *d)
 
                if (comedi_buf_put(s->async, bits)) {
                        s->async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS;
+                       if (s->async->cmd.stop_src == TRIG_COUNT &&
+                           subpriv->stop_count > 0) {
+                               subpriv->stop_count--;
+                               if (subpriv->stop_count == 0) {
+                                       /* end of acquisition */
+                                       s->async->events |= COMEDI_CB_EOA;
+                                       apci2032_int_stop(dev, s);
+                               }
+                       }
                } else {
                        apci2032_int_stop(dev, s);
                        s->async->events |= COMEDI_CB_OVERFLOW;