diff options
| author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2015-11-13 11:11:17 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-18 14:56:30 -0800 |
| commit | 976e893b61e628ff72adbf70ad84674650c8f053 (patch) | |
| tree | f3d19d3d5539624a1093f8b2d77cff76f531197d /drivers/staging/comedi/drivers/adv_pci1710.c | |
| parent | baacf6ca54291aec45babc4af079a39b64b02da3 (diff) | |
staging: comedi: adv_pci1710: support external analog output reference
The analog outputs can use an external reference to create the D/A output
range. Add an entry to the comedi_lrange table for it and modify the
(*insn_write) to support it.
Note that the D/A output range is 0 to +Vref with a -Vref. The comedi_lrange
does not include the sign of the range. It simmply allows the user to convert
between the 12-bit samples values (0x0000 - 0x0fff) and a physical value (0.0
to 1.0) using the comedilib comedi_to_phys() and comedi_from_phys() functions.
A physical value of 0.0 would actually be 0V with a -Vref and -V with a +Vref
and 1.0 would be +V with a -Vref and 0V with a -Vref. Ths user will need to
work this out but at least they can now use the external reference.
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/staging/comedi/drivers/adv_pci1710.c')
| -rw-r--r-- | drivers/staging/comedi/drivers/adv_pci1710.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c index cc451f131857..aafcb8adb1db 100644 --- a/drivers/staging/comedi/drivers/adv_pci1710.c +++ b/drivers/staging/comedi/drivers/adv_pci1710.c @@ -65,6 +65,8 @@ #define PCI171X_CLRFIFO_REG 0x09 /* W: clear FIFO */ #define PCI171X_DA_REG(x) (0x0a + ((x) * 2)) /* W: D/A register */ #define PCI171X_DAREF_REG 0x0e /* W: D/A reference control */ +#define PCI171X_DAREF(c, r) (((r) & 0x3) << ((c) * 2)) +#define PCI171X_DAREF_MASK(c) PCI171X_DAREF((c), 0x3) #define PCI171X_DI_REG 0x10 /* R: digital inputs */ #define PCI171X_DO_REG 0x10 /* W: digital outputs */ #define PCI171X_TIMER_BASE 0x18 /* R/W: 8254 timer */ @@ -111,9 +113,10 @@ static const struct comedi_lrange pci1711_ai_range = { }; static const struct comedi_lrange pci171x_ao_range = { - 2, { - UNI_RANGE(5), - UNI_RANGE(10) + 3, { + UNI_RANGE(5), /* internal -5V ref */ + UNI_RANGE(10), /* internal -10V ref */ + RANGE_ext(0, 1) /* external -Vref (+/-10V max) */ } }; @@ -631,8 +634,8 @@ static int pci1710_ao_insn_write(struct comedi_device *dev, unsigned int val = s->readback[chan]; int i; - devpriv->da_ranges &= ~(1 << (chan << 1)); - devpriv->da_ranges |= (range << (chan << 1)); + devpriv->da_ranges &= ~PCI171X_DAREF_MASK(chan); + devpriv->da_ranges |= PCI171X_DAREF(chan, range); outw(devpriv->da_ranges, dev->iobase + PCI171X_DAREF_REG); for (i = 0; i < insn->n; i++) { |