From 38020b55e7ced8398378b9023e41e9e1470b64cc Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 20 Nov 2014 15:10:45 -0700 Subject: [PATCH] staging: comedi: adv_pci1724: use subdevice readback for 'offset_value' Use the comedi_subdevice 'readback' member and the core provided (*insn_read) to handle the readback of the write-only offset calib subdevice. Remove the then unused 'offset_value' member from the private data. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/adv_pci1724.c | 31 ++++++---------------------- 1 file changed, 6 insertions(+), 25 deletions(-) diff --git a/drivers/staging/comedi/drivers/adv_pci1724.c b/drivers/staging/comedi/drivers/adv_pci1724.c index 7bbd36a..4aa1631 100644 --- a/drivers/staging/comedi/drivers/adv_pci1724.c +++ b/drivers/staging/comedi/drivers/adv_pci1724.c @@ -127,7 +127,6 @@ static const struct comedi_lrange ao_ranges_1724 = { /* this structure is for data unique to this hardware driver. */ struct adv_pci1724_private { - int offset_value[NUM_AO_CHANNELS]; int gain_value[NUM_AO_CHANNELS]; }; @@ -189,7 +188,6 @@ static int offset_write_insn(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { - struct adv_pci1724_private *devpriv = dev->private; int channel = CR_CHAN(insn->chanspec); int retval; int i; @@ -201,27 +199,8 @@ static int offset_write_insn(struct comedi_device *dev, retval = set_dac(dev, DAC_OFFSET_MODE, channel, data[i]); if (retval < 0) return retval; - devpriv->offset_value[channel] = data[i]; - } - - return insn->n; -} - -static int offset_read_insn(struct comedi_device *dev, - struct comedi_subdevice *s, - struct comedi_insn *insn, unsigned int *data) -{ - struct adv_pci1724_private *devpriv = dev->private; - unsigned int channel = CR_CHAN(insn->chanspec); - int i; - - if (devpriv->offset_value[channel] < 0) { - dev_err(dev->class_dev, - "Cannot read back channels which have not yet been written to\n"); - return -EIO; + s->readback[channel] = data[i]; } - for (i = 0; i < insn->n; i++) - data[i] = devpriv->offset_value[channel]; return insn->n; } @@ -296,9 +275,12 @@ static int setup_subdevices(struct comedi_device *dev) s->type = COMEDI_SUBD_CALIB; s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL; s->n_chan = NUM_AO_CHANNELS; - s->insn_read = offset_read_insn; - s->insn_write = offset_write_insn; s->maxdata = 0x3fff; + s->insn_write = offset_write_insn; + + ret = comedi_alloc_subdev_readback(s); + if (ret) + return ret; /* gain calibration */ s = &dev->subdevices[2]; @@ -328,7 +310,6 @@ static int adv_pci1724_auto_attach(struct comedi_device *dev, /* init software copies of output values to indicate we don't know * what the output value is since it has never been written. */ for (i = 0; i < NUM_AO_CHANNELS; ++i) { - devpriv->offset_value[i] = -1; devpriv->gain_value[i] = -1; } -- 2.7.4