diff options
| author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2014-03-10 21:07:40 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-03-17 21:04:00 (GMT) |
| commit | 8d9c93b4481f03a4f7658b97d6dc8996470a71e5 (patch) | |
| tree | 4788bd0baef61eaa07aa1647b805e412bc23282c /drivers | |
| parent | a7b31d3996a866408ebd6d16992d166b0207c7c1 (diff) | |
| download | linux-8d9c93b4481f03a4f7658b97d6dc8996470a71e5.tar.xz | |
staging: comedi: c6xdigio: add readback of last pwm channel values
Add and (*insn_read) for the PWM subdevice to allow reading back the
last value written to the channels.
There are only 2 PWM channels and they have a maxdata of 500. Pack
the last values in the subdevice 'state' instead of adding a private
data struct to this driver.
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/c6xdigio.c | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/drivers/staging/comedi/drivers/c6xdigio.c b/drivers/staging/comedi/drivers/c6xdigio.c index 20a5dfe..4114cf2 100644 --- a/drivers/staging/comedi/drivers/c6xdigio.c +++ b/drivers/staging/comedi/drivers/c6xdigio.c @@ -162,13 +162,41 @@ static int c6xdigio_pwm_insn_write(struct comedi_device *dev, unsigned int *data) { unsigned int chan = CR_CHAN(insn->chanspec); + unsigned int val = (s->state >> (16 * chan)) & 0xffff; int i; for (i = 0; i < insn->n; i++) { - c6xdigio_pwm_write(dev, chan, data[i]); - /* devpriv->ao_readback[chan] = data[i]; */ + val = data[i]; + c6xdigio_pwm_write(dev, chan, val); } - return i; + + /* + * There are only 2 PWM channels and they have a maxdata of 500. + * Instead of allocating private data to save the values in for + * readback this driver just packs the values for the two channels + * in the s->state. + */ + s->state &= (0xffff << (16 * chan)); + s->state |= (val << (16 * chan)); + + return insn->n; +} + +static int c6xdigio_pwm_insn_read(struct comedi_device *dev, + struct comedi_subdevice *s, + struct comedi_insn *insn, + unsigned int *data) +{ + unsigned int chan = CR_CHAN(insn->chanspec); + unsigned int val; + int i; + + val = (s->state >> (16 * chan)) & 0xffff; + + for (i = 0; i < insn->n; i++) + data[i] = val; + + return insn->n; } static int c6xdigio_encoder_insn_read(struct comedi_device *dev, @@ -243,6 +271,7 @@ static int c6xdigio_attach(struct comedi_device *dev, s->maxdata = 500; s->range_table = &range_unknown; s->insn_write = c6xdigio_pwm_insn_write; + s->insn_read = c6xdigio_pwm_insn_read; s = &dev->subdevices[1]; /* encoder (counter) subdevice */ |