1 files changed, 416 insertions, 149 deletions

diff --git a/drivers/staging/comedi/drivers/comedi_test.c b/drivers/staging/comedi/drivers/comedi_test.c
index 80d613c0fbc6..4ab186669f0c 100644
--- a/drivers/staging/comedi/drivers/comedi_test.c
+++ b/drivers/staging/comedi/drivers/comedi_test.c
@@ -1,49 +1,49 @@
 /*
-    comedi/drivers/comedi_test.c
+ * comedi/drivers/comedi_test.c
+ *
+ * Generates fake waveform signals that can be read through
+ * the command interface.  It does _not_ read from any board;
+ * it just generates deterministic waveforms.
+ * Useful for various testing purposes.
+ *
+ * Copyright (C) 2002 Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>
+ * Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
+ *
+ * COMEDI - Linux Control and Measurement Device Interface
+ * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
 
-    Generates fake waveform signals that can be read through
-    the command interface.  It does _not_ read from any board;
-    it just generates deterministic waveforms.
-    Useful for various testing purposes.
-
-    Copyright (C) 2002 Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>
-    Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
-
-    COMEDI - Linux Control and Measurement Device Interface
-    Copyright (C) 2000 David A. Schleef <ds@schleef.org>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-*/
 /*
-Driver: comedi_test
-Description: generates fake waveforms
-Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
-  <fmhess@users.sourceforge.net>, ds
-Devices:
-Status: works
-Updated: Sat, 16 Mar 2002 17:34:48 -0800
-
-This driver is mainly for testing purposes, but can also be used to
-generate sample waveforms on systems that don't have data acquisition
-hardware.
-
-Configuration options:
-  [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
-  [1] - Period in microseconds for fake waveforms (default 0.1 sec)
-
-Generates a sawtooth wave on channel 0, square wave on channel 1, additional
-waveforms could be added to other channels (currently they return flatline
-zero volts).
-
-*/
+ * Driver: comedi_test
+ * Description: generates fake waveforms
+ * Author: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess
+ *   <fmhess@users.sourceforge.net>, ds
+ * Devices:
+ * Status: works
+ * Updated: Sat, 16 Mar 2002 17:34:48 -0800
+ *
+ * This driver is mainly for testing purposes, but can also be used to
+ * generate sample waveforms on systems that don't have data acquisition
+ * hardware.
+ *
+ * Configuration options:
+ *   [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
+ *   [1] - Period in microseconds for fake waveforms (default 0.1 sec)
+ *
+ * Generates a sawtooth wave on channel 0, square wave on channel 1, additional
+ * waveforms could be added to other channels (currently they return flatline
+ * zero volts).
+ */
 
 #include <linux/module.h>
 #include "../comedidev.h"
@@ -52,30 +52,31 @@ zero volts).
 
 #include <linux/timer.h>
 #include <linux/ktime.h>
+#include <linux/jiffies.h>
 
 #define N_CHANS 8
 
 enum waveform_state_bits {
-	WAVEFORM_AI_RUNNING = 0
+	WAVEFORM_AI_RUNNING,
+	WAVEFORM_AO_RUNNING
 };
 
 /* Data unique to this driver */
 struct waveform_private {
-	struct timer_list timer;
-	ktime_t 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 (mod waveform period) */
-	unsigned long usec_remainder;	/* usec since last scan */
+	struct timer_list ai_timer;	/* timer for AI commands */
+	u64 ai_convert_time;		/* time of next AI conversion in usec */
+	unsigned int wf_amplitude;	/* waveform amplitude in microvolts */
+	unsigned int wf_period;		/* waveform period in microseconds */
+	unsigned int wf_current;	/* current time in waveform period */
 	unsigned long state_bits;
-	unsigned int scan_period;	/* scan period in usec */
-	unsigned int convert_period;	/* conversion period in usec */
-	unsigned int ao_loopbacks[N_CHANS];
+	unsigned int ai_scan_period;	/* AI scan period in usec */
+	unsigned int ai_convert_period;	/* AI conversion period in usec */
+	struct timer_list ao_timer;	/* timer for AO commands */
+	u64 ao_last_scan_time;		/* time of previous AO scan in usec */
+	unsigned int ao_scan_period;	/* AO scan period in usec */
+	unsigned short ao_loopbacks[N_CHANS];
 };
 
-/* 1000 nanosec in a microsec */
-static const int nano_per_micro = 1000;
-
 /* fake analog input ranges */
 static const struct comedi_lrange waveform_ai_ranges = {
 	2, {
@@ -86,7 +87,7 @@ static const struct comedi_lrange waveform_ai_ranges = {
 
 static unsigned short fake_sawtooth(struct comedi_device *dev,
 				    unsigned int range_index,
-				    unsigned long current_time)
+				    unsigned int current_time)
 {
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
@@ -97,21 +98,28 @@ static unsigned short fake_sawtooth(struct comedi_device *dev,
 	u64 binary_amplitude;
 
 	binary_amplitude = s->maxdata;
-	binary_amplitude *= devpriv->uvolt_amplitude;
+	binary_amplitude *= devpriv->wf_amplitude;
 	do_div(binary_amplitude, krange->max - krange->min);
 
-	current_time %= devpriv->usec_period;
 	value = current_time;
 	value *= binary_amplitude * 2;
-	do_div(value, devpriv->usec_period);
-	value -= binary_amplitude;	/* get rid of sawtooth's dc offset */
+	do_div(value, devpriv->wf_period);
+	value += offset;
+	/* get rid of sawtooth's dc offset and clamp value */
+	if (value < binary_amplitude) {
+		value = 0;			/* negative saturation */
+	} else {
+		value -= binary_amplitude;
+		if (value > s->maxdata)
+			value = s->maxdata;	/* positive saturation */
+	}
 
-	return offset + value;
+	return value;
 }
 
 static unsigned short fake_squarewave(struct comedi_device *dev,
 				      unsigned int range_index,
-				      unsigned long current_time)
+				      unsigned int current_time)
 {
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
@@ -119,21 +127,29 @@ static unsigned short fake_squarewave(struct comedi_device *dev,
 	u64 value;
 	const struct comedi_krange *krange =
 	    &s->range_table->range[range_index];
-	current_time %= devpriv->usec_period;
 
 	value = s->maxdata;
-	value *= devpriv->uvolt_amplitude;
+	value *= devpriv->wf_amplitude;
 	do_div(value, krange->max - krange->min);
 
-	if (current_time < devpriv->usec_period / 2)
-		value *= -1;
+	/* get one of two values for square-wave and clamp */
+	if (current_time < devpriv->wf_period / 2) {
+		if (offset < value)
+			value = 0;		/* negative saturation */
+		else
+			value = offset - value;
+	} else {
+		value += offset;
+		if (value > s->maxdata)
+			value = s->maxdata;	/* positive saturation */
+	}
 
-	return offset + value;
+	return value;
 }
 
 static unsigned short fake_flatline(struct comedi_device *dev,
 				    unsigned int range_index,
-				    unsigned long current_time)
+				    unsigned int current_time)
 {
 	return dev->read_subdev->maxdata / 2;
 }
@@ -141,7 +157,7 @@ static unsigned short fake_flatline(struct comedi_device *dev,
 /* generates a different waveform depending on what channel is read */
 static unsigned short fake_waveform(struct comedi_device *dev,
 				    unsigned int channel, unsigned int range,
-				    unsigned long current_time)
+				    unsigned int current_time)
 {
 	enum {
 		SAWTOOTH_CHAN,
@@ -160,58 +176,62 @@ static unsigned short fake_waveform(struct comedi_device *dev,
 }
 
 /*
-   This is the background routine used to generate arbitrary data.
-   It should run in the background; therefore it is scheduled by
-   a timer mechanism.
-*/
-static void waveform_ai_interrupt(unsigned long arg)
+ * This is the background routine used to generate arbitrary data.
+ * It should run in the background; therefore it is scheduled by
+ * a timer mechanism.
+ */
+static void waveform_ai_timer(unsigned long arg)
 {
 	struct comedi_device *dev = (struct comedi_device *)arg;
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
-	unsigned int i, j;
-	/* all times in microsec */
-	unsigned long elapsed_time;
-	unsigned int num_scans;
-	ktime_t now;
+	u64 now;
+	unsigned int nsamples;
+	unsigned int time_increment;
 
 	/* check command is still active */
 	if (!test_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits))
 		return;
 
-	now = ktime_get();
-
-	elapsed_time = ktime_to_us(ktime_sub(now, devpriv->last));
-	devpriv->last = now;
-	num_scans =
-	    (devpriv->usec_remainder + elapsed_time) / devpriv->scan_period;
-	devpriv->usec_remainder =
-	    (devpriv->usec_remainder + elapsed_time) % devpriv->scan_period;
-
-	num_scans = comedi_nscans_left(s, num_scans);
-	for (i = 0; i < num_scans; i++) {
-		for (j = 0; j < cmd->chanlist_len; j++) {
-			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);
-			comedi_buf_write_samples(s, &sample, 1);
+	now = ktime_to_us(ktime_get());
+	nsamples = comedi_nsamples_left(s, UINT_MAX);
+
+	while (nsamples && devpriv->ai_convert_time < now) {
+		unsigned int chanspec = cmd->chanlist[async->cur_chan];
+		unsigned short sample;
+
+		sample = fake_waveform(dev, CR_CHAN(chanspec),
+				       CR_RANGE(chanspec), devpriv->wf_current);
+		if (comedi_buf_write_samples(s, &sample, 1) == 0)
+			goto overrun;
+		time_increment = devpriv->ai_convert_period;
+		if (async->scan_progress == 0) {
+			/* done last conversion in scan, so add dead time */
+			time_increment += devpriv->ai_scan_period -
+					  devpriv->ai_convert_period *
+					  cmd->scan_end_arg;
 		}
+		devpriv->wf_current += time_increment;
+		if (devpriv->wf_current >= devpriv->wf_period)
+			devpriv->wf_current %= devpriv->wf_period;
+		devpriv->ai_convert_time += time_increment;
+		nsamples--;
 	}
 
-	devpriv->usec_current += elapsed_time;
-	devpriv->usec_current %= devpriv->usec_period;
-
-	if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg)
+	if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) {
 		async->events |= COMEDI_CB_EOA;
-	else
-		mod_timer(&devpriv->timer, jiffies + 1);
+	} else {
+		if (devpriv->ai_convert_time > now)
+			time_increment = devpriv->ai_convert_time - now;
+		else
+			time_increment = 1;
+		mod_timer(&devpriv->ai_timer,
+			  jiffies + usecs_to_jiffies(time_increment));
+	}
 
+overrun:
 	comedi_handle_events(dev, s);
 }
 
@@ -220,12 +240,13 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
 			       struct comedi_cmd *cmd)
 {
 	int err = 0;
-	unsigned int arg;
+	unsigned int arg, limit;
 
 	/* Step 1 : check if triggers are trivially valid */
 
 	err |= comedi_check_trigger_src(&cmd->start_src, TRIG_NOW);
-	err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
+	err |= comedi_check_trigger_src(&cmd->scan_begin_src,
+					TRIG_FOLLOW | TRIG_TIMER);
 	err |= comedi_check_trigger_src(&cmd->convert_src,
 					TRIG_NOW | TRIG_TIMER);
 	err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
@@ -241,6 +262,9 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
 
 	/* Step 2b : and mutually compatible */
 
+	if (cmd->scan_begin_src == TRIG_FOLLOW && cmd->convert_src == TRIG_NOW)
+		err |= -EINVAL;		/* scan period would be 0 */
+
 	if (err)
 		return 2;
 
@@ -248,18 +272,20 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
 
 	err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
 
-	if (cmd->convert_src == TRIG_NOW)
+	if (cmd->convert_src == TRIG_NOW) {
 		err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
+	} else {	/* cmd->convert_src == TRIG_TIMER */
+		if (cmd->scan_begin_src == TRIG_FOLLOW) {
+			err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
+							    NSEC_PER_USEC);
+		}
+	}
 
-	if (cmd->scan_begin_src == TRIG_TIMER) {
+	if (cmd->scan_begin_src == TRIG_FOLLOW) {
+		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
+	} else {	/* cmd->scan_begin_src == TRIG_TIMER */
 		err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
-						    nano_per_micro);
-		if (cmd->convert_src == TRIG_TIMER) {
-			err |= comedi_check_trigger_arg_min(&cmd->
-							    scan_begin_arg,
-							    cmd->convert_arg *
-							    cmd->chanlist_len);
-		}
+						    NSEC_PER_USEC);
 	}
 
 	err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
@@ -268,7 +294,7 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
 
 	if (cmd->stop_src == TRIG_COUNT)
 		err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
-	else	/* TRIG_NONE */
+	else	/* cmd->stop_src == TRIG_NONE */
 		err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -276,21 +302,34 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
 
 	/* step 4: fix up any arguments */
 
-	if (cmd->scan_begin_src == TRIG_TIMER) {
-		arg = cmd->scan_begin_arg;
-		/* round to nearest microsec */
-		arg = nano_per_micro *
-		      ((arg + (nano_per_micro / 2)) / nano_per_micro);
-		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
-	}
 	if (cmd->convert_src == TRIG_TIMER) {
+		/* round convert_arg to nearest microsecond */
 		arg = cmd->convert_arg;
-		/* round to nearest microsec */
-		arg = nano_per_micro *
-		      ((arg + (nano_per_micro / 2)) / nano_per_micro);
+		arg = min(arg,
+			  rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
+		arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
+		if (cmd->scan_begin_arg == TRIG_TIMER) {
+			/* limit convert_arg to keep scan_begin_arg in range */
+			limit = UINT_MAX / cmd->scan_end_arg;
+			limit = rounddown(limit, (unsigned int)NSEC_PER_SEC);
+			arg = min(arg, limit);
+		}
 		err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
 	}
 
+	if (cmd->scan_begin_src == TRIG_TIMER) {
+		/* round scan_begin_arg to nearest microsecond */
+		arg = cmd->scan_begin_arg;
+		arg = min(arg,
+			  rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
+		arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
+		if (cmd->convert_src == TRIG_TIMER) {
+			/* but ensure scan_begin_arg is large enough */
+			arg = max(arg, cmd->convert_arg * cmd->scan_end_arg);
+		}
+		err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
+	}
+
 	if (err)
 		return 4;
 
@@ -302,6 +341,8 @@ static int waveform_ai_cmd(struct comedi_device *dev,
 {
 	struct waveform_private *devpriv = dev->private;
 	struct comedi_cmd *cmd = &s->async->cmd;
+	unsigned int first_convert_time;
+	u64 wf_current;
 
 	if (cmd->flags & CMDF_PRIORITY) {
 		dev_err(dev->class_dev,
@@ -309,24 +350,48 @@ static int waveform_ai_cmd(struct comedi_device *dev,
 		return -1;
 	}
 
-	devpriv->scan_period = cmd->scan_begin_arg / nano_per_micro;
-
 	if (cmd->convert_src == TRIG_NOW)
-		devpriv->convert_period = 0;
-	else	/* TRIG_TIMER */
-		devpriv->convert_period = cmd->convert_arg / nano_per_micro;
+		devpriv->ai_convert_period = 0;
+	else		/* cmd->convert_src == TRIG_TIMER */
+		devpriv->ai_convert_period = cmd->convert_arg / NSEC_PER_USEC;
+
+	if (cmd->scan_begin_src == TRIG_FOLLOW) {
+		devpriv->ai_scan_period = devpriv->ai_convert_period *
+					  cmd->scan_end_arg;
+	} else {	/* cmd->scan_begin_src == TRIG_TIMER */
+		devpriv->ai_scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
+	}
 
-	devpriv->last = ktime_get();
-	devpriv->usec_current =
-		((u32)ktime_to_us(devpriv->last)) % devpriv->usec_period;
-	devpriv->usec_remainder = 0;
+	/*
+	 * Simulate first conversion to occur at convert period after
+	 * conversion timer starts.  If scan_begin_src is TRIG_FOLLOW, assume
+	 * the conversion timer starts immediately.  If scan_begin_src is
+	 * TRIG_TIMER, assume the conversion timer starts after the scan
+	 * period.
+	 */
+	first_convert_time = devpriv->ai_convert_period;
+	if (cmd->scan_begin_src == TRIG_TIMER)
+		first_convert_time += devpriv->ai_scan_period;
+	devpriv->ai_convert_time = ktime_to_us(ktime_get()) +
+				   first_convert_time;
+
+	/* Determine time within waveform period at time of conversion. */
+	wf_current = devpriv->ai_convert_time;
+	devpriv->wf_current = do_div(wf_current, devpriv->wf_period);
+
+	/*
+	 * Schedule timer to expire just after first conversion time.
+	 * Seem to need an extra jiffy here, otherwise timer expires slightly
+	 * early!
+	 */
+	devpriv->ai_timer.expires =
+		jiffies + usecs_to_jiffies(devpriv->ai_convert_period) + 1;
 
-	devpriv->timer.expires = jiffies + 1;
 	/* mark command as active */
 	smp_mb__before_atomic();
 	set_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 	smp_mb__after_atomic();
-	add_timer(&devpriv->timer);
+	add_timer(&devpriv->ai_timer);
 	return 0;
 }
 
@@ -339,7 +404,7 @@ static int waveform_ai_cancel(struct comedi_device *dev,
 	clear_bit(WAVEFORM_AI_RUNNING, &devpriv->state_bits);
 	smp_mb__after_atomic();
 	/* cannot call del_timer_sync() as may be called from timer routine */
-	del_timer(&devpriv->timer);
+	del_timer(&devpriv->ai_timer);
 	return 0;
 }
 
@@ -356,6 +421,201 @@ static int waveform_ai_insn_read(struct comedi_device *dev,
 	return insn->n;
 }
 
+/*
+ * This is the background routine to handle AO commands, scheduled by
+ * a timer mechanism.
+ */
+static void waveform_ao_timer(unsigned long arg)
+{
+	struct comedi_device *dev = (struct comedi_device *)arg;
+	struct waveform_private *devpriv = dev->private;
+	struct comedi_subdevice *s = dev->write_subdev;
+	struct comedi_async *async = s->async;
+	struct comedi_cmd *cmd = &async->cmd;
+	u64 now;
+	u64 scans_since;
+	unsigned int scans_avail = 0;
+
+	/* check command is still active */
+	if (!test_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits))
+		return;
+
+	/* determine number of scan periods since last time */
+	now = ktime_to_us(ktime_get());
+	scans_since = now - devpriv->ao_last_scan_time;
+	do_div(scans_since, devpriv->ao_scan_period);
+	if (scans_since) {
+		unsigned int i;
+
+		/* determine scans in buffer, limit to scans to do this time */
+		scans_avail = comedi_nscans_left(s, 0);
+		if (scans_avail > scans_since)
+			scans_avail = scans_since;
+		if (scans_avail) {
+			/* skip all but the last scan to save processing time */
+			if (scans_avail > 1) {
+				unsigned int skip_bytes, nbytes;
+
+				skip_bytes =
+				comedi_samples_to_bytes(s, cmd->scan_end_arg *
+							   (scans_avail - 1));
+				nbytes = comedi_buf_read_alloc(s, skip_bytes);
+				comedi_buf_read_free(s, nbytes);
+				comedi_inc_scan_progress(s, nbytes);
+				if (nbytes < skip_bytes) {
+					/* unexpected underrun! (cancelled?) */
+					async->events |= COMEDI_CB_OVERFLOW;
+					goto underrun;
+				}
+			}
+			/* output the last scan */
+			for (i = 0; i < cmd->scan_end_arg; i++) {
+				unsigned int chan = CR_CHAN(cmd->chanlist[i]);
+
+				if (comedi_buf_read_samples(s,
+							    &devpriv->
+							     ao_loopbacks[chan],
+							    1) == 0) {
+					/* unexpected underrun! (cancelled?) */
+					async->events |= COMEDI_CB_OVERFLOW;
+					goto underrun;
+				}
+			}
+			/* advance time of last scan */
+			devpriv->ao_last_scan_time +=
+				(u64)scans_avail * devpriv->ao_scan_period;
+		}
+	}
+	if (cmd->stop_src == TRIG_COUNT && async->scans_done >= cmd->stop_arg) {
+		async->events |= COMEDI_CB_EOA;
+	} else if (scans_avail < scans_since) {
+		async->events |= COMEDI_CB_OVERFLOW;
+	} else {
+		unsigned int time_inc = devpriv->ao_last_scan_time +
+					devpriv->ao_scan_period - now;
+
+		mod_timer(&devpriv->ao_timer,
+			  jiffies + usecs_to_jiffies(time_inc));
+	}
+
+underrun:
+	comedi_handle_events(dev, s);
+}
+
+static int waveform_ao_inttrig_start(struct comedi_device *dev,
+				     struct comedi_subdevice *s,
+				     unsigned int trig_num)
+{
+	struct waveform_private *devpriv = dev->private;
+	struct comedi_async *async = s->async;
+	struct comedi_cmd *cmd = &async->cmd;
+
+	if (trig_num != cmd->start_arg)
+		return -EINVAL;
+
+	async->inttrig = NULL;
+
+	devpriv->ao_last_scan_time = ktime_to_us(ktime_get());
+	devpriv->ao_timer.expires =
+		jiffies + usecs_to_jiffies(devpriv->ao_scan_period);
+
+	/* mark command as active */
+	smp_mb__before_atomic();
+	set_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits);
+	smp_mb__after_atomic();
+	add_timer(&devpriv->ao_timer);
+
+	return 1;
+}
+
+static int waveform_ao_cmdtest(struct comedi_device *dev,
+			       struct comedi_subdevice *s,
+			       struct comedi_cmd *cmd)
+{
+	int err = 0;
+	unsigned int arg;
+
+	/* Step 1 : check if triggers are trivially valid */
+
+	err |= comedi_check_trigger_src(&cmd->start_src, TRIG_INT);
+	err |= comedi_check_trigger_src(&cmd->scan_begin_src, TRIG_TIMER);
+	err |= comedi_check_trigger_src(&cmd->convert_src, TRIG_NOW);
+	err |= comedi_check_trigger_src(&cmd->scan_end_src, TRIG_COUNT);
+	err |= comedi_check_trigger_src(&cmd->stop_src, TRIG_COUNT | TRIG_NONE);
+
+	if (err)
+		return 1;
+
+	/* Step 2a : make sure trigger sources are unique */
+
+	err |= comedi_check_trigger_is_unique(cmd->stop_src);
+
+	/* Step 2b : and mutually compatible */
+
+	if (err)
+		return 2;
+
+	/* Step 3: check if arguments are trivially valid */
+
+	err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
+					    NSEC_PER_USEC);
+	err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
+	err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
+	err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
+					   cmd->chanlist_len);
+	if (cmd->stop_src == TRIG_COUNT)
+		err |= comedi_check_trigger_arg_min(&cmd->stop_arg, 1);
+	else	/* cmd->stop_src == TRIG_NONE */
+		err |= comedi_check_trigger_arg_is(&cmd->stop_arg, 0);
+
+	if (err)
+		return 3;
+
+	/* step 4: fix up any arguments */
+
+	/* round scan_begin_arg to nearest microsecond */
+	arg = cmd->scan_begin_arg;
+	arg = min(arg, rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
+	arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
+	err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
+
+	if (err)
+		return 4;
+
+	return 0;
+}
+
+static int waveform_ao_cmd(struct comedi_device *dev,
+			   struct comedi_subdevice *s)
+{
+	struct waveform_private *devpriv = dev->private;
+	struct comedi_cmd *cmd = &s->async->cmd;
+
+	if (cmd->flags & CMDF_PRIORITY) {
+		dev_err(dev->class_dev,
+			"commands at RT priority not supported in this driver\n");
+		return -1;
+	}
+
+	devpriv->ao_scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
+	s->async->inttrig = waveform_ao_inttrig_start;
+	return 0;
+}
+
+static int waveform_ao_cancel(struct comedi_device *dev,
+			      struct comedi_subdevice *s)
+{
+	struct waveform_private *devpriv = dev->private;
+
+	s->async->inttrig = NULL;
+	/* mark command as no longer active */
+	clear_bit(WAVEFORM_AO_RUNNING, &devpriv->state_bits);
+	smp_mb__after_atomic();
+	/* cannot call del_timer_sync() as may be called from timer routine */
+	del_timer(&devpriv->ao_timer);
+	return 0;
+}
+
 static int waveform_ao_insn_write(struct comedi_device *dev,
 				  struct comedi_subdevice *s,
 				  struct comedi_insn *insn, unsigned int *data)
@@ -389,8 +649,8 @@ static int waveform_attach(struct comedi_device *dev,
 	if (period <= 0)
 		period = 100000;	/* 0.1 sec */
 
-	devpriv->uvolt_amplitude = amplitude;
-	devpriv->usec_period = period;
+	devpriv->wf_amplitude = amplitude;
+	devpriv->wf_period = period;
 
 	ret = comedi_alloc_subdevices(dev, 2);
 	if (ret)
@@ -414,23 +674,28 @@ static int waveform_attach(struct comedi_device *dev,
 	dev->write_subdev = s;
 	/* analog output subdevice (loopback) */
 	s->type = COMEDI_SUBD_AO;
-	s->subdev_flags = SDF_WRITABLE | SDF_GROUND;
+	s->subdev_flags = SDF_WRITABLE | SDF_GROUND | SDF_CMD_WRITE;
 	s->n_chan = N_CHANS;
 	s->maxdata = 0xffff;
 	s->range_table = &waveform_ai_ranges;
+	s->len_chanlist = s->n_chan;
 	s->insn_write = waveform_ao_insn_write;
+	s->insn_read = waveform_ai_insn_read;	/* do same as AI insn_read */
+	s->do_cmd = waveform_ao_cmd;
+	s->do_cmdtest = waveform_ao_cmdtest;
+	s->cancel = waveform_ao_cancel;
 
 	/* Our default loopback value is just a 0V flatline */
 	for (i = 0; i < s->n_chan; i++)
 		devpriv->ao_loopbacks[i] = s->maxdata / 2;
 
-	setup_timer(&devpriv->timer, waveform_ai_interrupt,
-		    (unsigned long)dev);
+	setup_timer(&devpriv->ai_timer, waveform_ai_timer, (unsigned long)dev);
+	setup_timer(&devpriv->ao_timer, waveform_ao_timer, (unsigned long)dev);
 
 	dev_info(dev->class_dev,
-		 "%s: %i microvolt, %li microsecond waveform attached\n",
+		 "%s: %u microvolt, %u microsecond waveform attached\n",
 		 dev->board_name,
-		 devpriv->uvolt_amplitude, devpriv->usec_period);
+		 devpriv->wf_amplitude, devpriv->wf_period);
 
 	return 0;
 }
@@ -439,8 +704,10 @@ static void waveform_detach(struct comedi_device *dev)
 {
 	struct waveform_private *devpriv = dev->private;
 
-	if (devpriv)
-		del_timer_sync(&devpriv->timer);
+	if (devpriv) {
+		del_timer_sync(&devpriv->ai_timer);
+		del_timer_sync(&devpriv->ao_timer);
+	}
 }
 
 static struct comedi_driver waveform_driver = {