The external pin TGIN can be used to start and/or stop the analog input
command. Currently the driver only supports negative edge polarity for
this signal.
Add support to allow the user to select positive edge polarity using
the CR_INVERT flag.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/das1800.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/drivers/das1800.c b/drivers/staging/comedi/drivers/das1800.c
index bfbc2bb..875b6f5 100644
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -60,6 +60,9 @@
* If TRIG_EXT is used for both the start_src and stop_src, the first TGIN
* trigger starts the command, and the second trigger will stop it. If only
* one is TRIG_EXT, the first trigger will either stop or start the command.
+ * The external pin TGIN is normally set for negative edge triggering. It
+ * can be set to positive edge with the CR_INVERT flag. If TRIG_EXT is used
+ * for both the start_src and stop_src they must have the same polarity.
*
* Minimum conversion speed is limited to 64 microseconds (convert_arg <= 64000)
* for 'burst' scans. This limitation does not apply for 'paced' scans. The
@@ -105,6 +108,7 @@
#define CGSL 0x8
#define TGEN 0x10
#define TGSL 0x20
+#define TGPL 0x40
#define ATEN 0x80
#define DAS1800_CONTROL_B 0x5
#define DMA_CH5 0x1
@@ -671,12 +675,18 @@ static int das1800_ai_cmdtest(struct comedi_device *dev,
cmd->convert_src != TRIG_TIMER)
err |= -EINVAL;
+ /* the external pin TGIN must use the same polarity */
+ if (cmd->start_src == TRIG_EXT && cmd->stop_src == TRIG_EXT)
+ err |= comedi_check_trigger_arg_is(&cmd->start_arg,
+ cmd->stop_arg);
+
if (err)
return 2;
/* Step 3: check if arguments are trivially valid */
- err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
+ if (cmd->start_arg == TRIG_NOW)
+ err |= comedi_check_trigger_arg_is(&cmd->start_arg, 0);
if (cmd->convert_src == TRIG_TIMER) {
err |= comedi_check_trigger_arg_min(&cmd->convert_arg,
@@ -868,6 +878,10 @@ static int das1800_ai_cmd(struct comedi_device *dev,
control_a |= TGEN | CGSL;
else /* TRIG_NOW */
control_a |= CGEN;
+ if (control_a & (ATEN | TGEN)) {
+ if ((cmd->start_arg & CR_INVERT) || (cmd->stop_arg & CR_INVERT))
+ control_a |= TGPL;
+ }
control_c = das1800_ai_chanspec_bits(s, cmd->chanlist[0]);
/* set clock source to internal or external */
--
2.6.3
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