1 files changed, 37 insertions, 38 deletions

diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
index 01de996239f1..270fea5c6b51 100644
--- a/drivers/staging/comedi/drivers/comedi_test.c
+++ b/drivers/staging/comedi/drivers/comedi_test.c
@@ -62,15 +62,14 @@ zero volts).
 /* Data unique to this driver */
 struct waveform_private {
 	struct timer_list timer;
-	struct timeval last;	/* time at which last timer interrupt occurred */
+	struct timeval last;		/* time last timer interrupt occurred */
 	unsigned int uvolt_amplitude;	/* waveform amplitude in microvolts */
 	unsigned long usec_period;	/* waveform period in microseconds */
-	unsigned long usec_current;	/* current time (modulo waveform period) */
-	unsigned long usec_remainder;	/* usec since last scan; */
-	unsigned long ai_count;	/* number of conversions remaining */
+	unsigned long usec_current;	/* current time (mod waveform period) */
+	unsigned long usec_remainder;	/* usec since last scan */
+	unsigned long ai_count;		/* number of conversions remaining */
 	unsigned int scan_period;	/* scan period in usec */
 	unsigned int convert_period;	/* conversion period in usec */
-	unsigned timer_running:1;
 	unsigned int ao_loopbacks[N_CHANS];
 };
 
@@ -86,8 +85,9 @@ static const struct comedi_lrange waveform_ai_ranges = {
 	 }
 };
 
-static short fake_sawtooth(struct comedi_device *dev, unsigned int range_index,
-			   unsigned long current_time)
+static unsigned short fake_sawtooth(struct comedi_device *dev,
+				    unsigned int range_index,
+				    unsigned long current_time)
 {
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
@@ -110,9 +110,9 @@ static short fake_sawtooth(struct comedi_device *dev, unsigned int range_index,
 	return offset + value;
 }
 
-static short fake_squarewave(struct comedi_device *dev,
-			     unsigned int range_index,
-			     unsigned long current_time)
+static unsigned short fake_squarewave(struct comedi_device *dev,
+				      unsigned int range_index,
+				      unsigned long current_time)
 {
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
@@ -132,15 +132,17 @@ static short fake_squarewave(struct comedi_device *dev,
 	return offset + value;
 }
 
-static short fake_flatline(struct comedi_device *dev, unsigned int range_index,
-			   unsigned long current_time)
+static unsigned short fake_flatline(struct comedi_device *dev,
+				    unsigned int range_index,
+				    unsigned long current_time)
 {
 	return dev->read_subdev->maxdata / 2;
 }
 
 /* generates a different waveform depending on what channel is read */
-static short fake_waveform(struct comedi_device *dev, unsigned int channel,
-			   unsigned int range, unsigned long current_time)
+static unsigned short fake_waveform(struct comedi_device *dev,
+				    unsigned int channel, unsigned int range,
+				    unsigned long current_time)
 {
 	enum {
 		SAWTOOTH_CHAN,
@@ -176,6 +178,7 @@ static void waveform_ai_interrupt(unsigned long arg)
 	unsigned long elapsed_time;
 	unsigned int num_scans;
 	struct timeval now;
+	bool stopping = false;
 
 	do_gettimeofday(&now);
 
@@ -189,37 +192,35 @@ static void waveform_ai_interrupt(unsigned long arg)
 	    (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
 	async->events = 0;
 
+	if (cmd->stop_src == TRIG_COUNT) {
+		unsigned int remaining = cmd->stop_arg - devpriv->ai_count;
+		if (num_scans >= remaining) {
+			/* about to finish */
+			num_scans = remaining;
+			stopping = true;
+		}
+	}
+
 	for (i = 0; i < num_scans; i++) {
 		for (j = 0; j < cmd->chanlist_len; j++) {
-			cfc_write_to_buffer(dev->read_subdev,
-					    fake_waveform(dev,
-							  CR_CHAN(cmd->
-								  chanlist[j]),
-							  CR_RANGE(cmd->
-								   chanlist[j]),
-							  devpriv->
-							  usec_current +
-							  i *
-							  devpriv->scan_period +
-							  j *
-							  devpriv->
-							  convert_period));
-		}
-		devpriv->ai_count++;
-		if (cmd->stop_src == TRIG_COUNT
-		    && devpriv->ai_count >= cmd->stop_arg) {
-			async->events |= COMEDI_CB_EOA;
-			break;
+			unsigned short sample;
+			sample = fake_waveform(dev, CR_CHAN(cmd->chanlist[j]),
+					       CR_RANGE(cmd->chanlist[j]),
+					       devpriv->usec_current +
+						   i * devpriv->scan_period +
+						   j * devpriv->convert_period);
+			cfc_write_to_buffer(dev->read_subdev, sample);
 		}
 	}
 
+	devpriv->ai_count += i;
 	devpriv->usec_current += elapsed_time;
 	devpriv->usec_current %= devpriv->usec_period;
 
-	if ((async->events & COMEDI_CB_EOA) == 0 && devpriv->timer_running)
-		mod_timer(&devpriv->timer, jiffies + 1);
+	if (stopping)
+		async->events |= COMEDI_CB_EOA;
 	else
-		del_timer(&devpriv->timer);
+		mod_timer(&devpriv->timer, jiffies + 1);
 
 	comedi_event(dev, dev->read_subdev);
 }
@@ -317,7 +318,6 @@ static int waveform_ai_cmd(struct comedi_device *dev,
 		return -1;
 	}
 
-	devpriv->timer_running = 1;
 	devpriv->ai_count = 0;
 	devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
 
@@ -344,7 +344,6 @@ static int waveform_ai_cancel(struct comedi_device *dev,
 {
 	struct waveform_private *devpriv = dev->private;
 
-	devpriv->timer_running = 0;
 	del_timer_sync(&devpriv->timer);
 	return 0;
 }