From 130151991dcb14e5c383c730b3ef37a6fdc32c95 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Tue, 30 Oct 2018 14:17:11 +0000 Subject: [PATCH] staging: comedi: cb_pcidas64: Use insn->n in AO insn_write handler The `insn_write` handler for the AO subdevice (`ao_winsn()` currently ignores `insn->n` (the number of samples to write) and assumes a single sample is to be written. But `insn->n` could be 0, meaning no samples should be written, in which case `data[0]` is invalid. Follow the usual Comedi guidelines and change `ao_winsn()` to write the specified number of samples. This fixes the assumption that `data[0]` is valid. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/cb_pcidas64.c | 32 +++++++++++++++++----------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/drivers/staging/comedi/drivers/cb_pcidas64.c b/drivers/staging/comedi/drivers/cb_pcidas64.c index 631a703..44e5aaf 100644 --- a/drivers/staging/comedi/drivers/cb_pcidas64.c +++ b/drivers/staging/comedi/drivers/cb_pcidas64.c @@ -3097,8 +3097,10 @@ static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s, { const struct pcidas64_board *board = dev->board_ptr; struct pcidas64_private *devpriv = dev->private; - int chan = CR_CHAN(insn->chanspec); - int range = CR_RANGE(insn->chanspec); + unsigned int chan = CR_CHAN(insn->chanspec); + unsigned int range = CR_RANGE(insn->chanspec); + unsigned int val = s->readback[chan]; + unsigned int i; /* do some initializing */ writew(0, devpriv->main_iobase + DAC_CONTROL0_REG); @@ -3108,20 +3110,24 @@ static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s, writew(devpriv->dac_control1_bits, devpriv->main_iobase + DAC_CONTROL1_REG); - /* write to channel */ - if (board->layout == LAYOUT_4020) { - writew(data[0] & 0xff, - devpriv->main_iobase + dac_lsb_4020_reg(chan)); - writew((data[0] >> 8) & 0xf, - devpriv->main_iobase + dac_msb_4020_reg(chan)); - } else { - writew(data[0], devpriv->main_iobase + dac_convert_reg(chan)); + for (i = 0; i < insn->n; i++) { + /* write to channel */ + val = data[i]; + if (board->layout == LAYOUT_4020) { + writew(val & 0xff, + devpriv->main_iobase + dac_lsb_4020_reg(chan)); + writew((val >> 8) & 0xf, + devpriv->main_iobase + dac_msb_4020_reg(chan)); + } else { + writew(val, + devpriv->main_iobase + dac_convert_reg(chan)); + } } - /* remember output value */ - s->readback[chan] = data[0]; + /* remember last output value */ + s->readback[chan] = val; - return 1; + return insn->n; } static void set_dac_control0_reg(struct comedi_device *dev, -- 2.7.4