From 388674e0a92f2bf4ce6ddd3758b0cef906b55ce4 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 20 Nov 2014 15:10:44 -0700 Subject: [PATCH] staging: comedi: adv_pci1724: use subdevice readback for 'ao_value' Use the comedi_subdevice 'readback' member and the core provided (*insn_read) to handle the readback of the write-only analog output subdevice. Remove the then unused 'ao_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 | 29 ++++---------------- 1 file changed, 5 insertions(+), 24 deletions(-) diff --git a/drivers/staging/comedi/drivers/adv_pci1724.c b/drivers/staging/comedi/drivers/adv_pci1724.c index 2697758b1ed9..7bbd36ae0791 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 ao_value[NUM_AO_CHANNELS]; int offset_value[NUM_AO_CHANNELS]; int gain_value[NUM_AO_CHANNELS]; }; @@ -170,7 +169,6 @@ static int set_dac(struct comedi_device *dev, unsigned mode, unsigned channel, static int ao_winsn(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; @@ -182,27 +180,8 @@ static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s, retval = set_dac(dev, DAC_NORMAL_MODE, channel, data[i]); if (retval < 0) return retval; - devpriv->ao_value[channel] = data[i]; - } - return insn->n; -} - -static int ao_readback_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 i; - - if (devpriv->ao_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->ao_value[channel]; - return insn->n; } @@ -306,9 +285,12 @@ static int setup_subdevices(struct comedi_device *dev) s->n_chan = NUM_AO_CHANNELS; s->maxdata = 0x3fff; s->range_table = &ao_ranges_1724; - s->insn_read = ao_readback_insn; s->insn_write = ao_winsn; + ret = comedi_alloc_subdev_readback(s); + if (ret) + return ret; + /* offset calibration */ s = &dev->subdevices[1]; s->type = COMEDI_SUBD_CALIB; @@ -346,7 +328,6 @@ 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->ao_value[i] = -1; devpriv->offset_value[i] = -1; devpriv->gain_value[i] = -1; } -- 2.34.1