diff options
| author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2016-04-08 12:42:05 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-28 22:16:10 -0700 |
| commit | a6b7dbb2be27636e80e4124f157e08b33e451b80 (patch) | |
| tree | b9be3ac09f2854919e69ddd89d64509020931680 /drivers | |
| parent | a2706b094353b6210446af3be174c9eddfd7ce01 (diff) | |
staging: comedi: das1800: allow setting the external trigger polarity
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@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/staging/comedi/drivers/das1800.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/staging/comedi/drivers/das1800.c b/drivers/staging/comedi/drivers/das1800.c index bfbc2bbbce10..875b6f504626 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 */ |