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staging: comedi: comedi_test: support scan_begin_src == TRIG_FOLLOW

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It is quite common for COMEDI subdevices that support commands to
support setting `scan_begin_src` to `TRIG_FOLLOW`.  This means the next
scan begins once all conversions in the current scan are complete.
Support the following timing combinations for the AI subdevice:

  scan_begin_src == TRIG_TIMER && convert_src == TRIG_TIMER
  scan_begin_src == TRIG_TIMER && convert_src == TRIG_NOW
  scan_begin_src == TRIG_FOLLOW && convert_src == TRIG_TIMER

The actual scan period in microseconds is stored in the `scan_period`
member of the private data structure `struct waveform_private`.  An
`unsigned int` is still wide enough, because the conversion period is no
more than `UINT_MAX / 1000` microseconds and the number of conversions
is no more than 16 (`N_CHANS * 2`).

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2015-10-27 16:59:14 +00:00 committed by Greg Kroah-Hartman
parent 5afdcad2f8
commit 783ddaebd3
1 changed files with 44 additions and 20 deletions
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64
drivers/staging/comedi/drivers/comedi_test.c
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@ -239,7 +239,8 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
/* 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);
@ -255,6 +256,9 @@ 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;
@ -262,11 +266,21 @@ 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);
}
}
err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
NSEC_PER_USEC);
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,
NSEC_PER_USEC);
}
err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
@ -274,7 +288,7 @@ 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)
@ -288,22 +302,27 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
arg = min(arg,
rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
/* 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);
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);
}
/* 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);
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);
}
err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
if (err)
return 4;
@ -323,13 +342,18 @@ static int waveform_ai_cmd(struct comedi_device *dev,
return -1;
}
devpriv->scan_period = cmd->scan_begin_arg / NSEC_PER_USEC;
if (cmd->convert_src == TRIG_NOW)
devpriv->convert_period = 0;
else /* TRIG_TIMER */
else /* cmd->convert_src == TRIG_TIMER */
devpriv->convert_period = cmd->convert_arg / NSEC_PER_USEC;
if (cmd->scan_begin_src == TRIG_FOLLOW) {
devpriv->scan_period = devpriv->convert_period *
cmd->scan_end_arg;
} else { /* cmd->scan_begin_src == TRIG_TIMER */
devpriv->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;