das08: don't access *data when insn->n == 0

Due to recent change to do_insnlist_ioctl() and do_insn_ioctl(), the
'data' pointer will be NULL when insn->n == 0.  Do not access *data
in this case.

Also handle INSN_WRITE properly for AO subdevices.  Should use the nth
data value in the loop, not the 0th.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

diff --git a/comedi/drivers/das08.c b/comedi/drivers/das08.c
index 78b5038e93d05cb0bcd4db0a5dd6b94aa04307ba..9d9e7bbb313b3b97d3170c6016bcb92addcb0fc4 100644 (file)
--- a/comedi/drivers/das08.c
+++ b/comedi/drivers/das08.c
@@ -641,12 +641,11 @@ static int das08jr_ao_winsn(comedi_device * dev, comedi_subdevice * s,
        int lsb, msb;
        int chan;
 
-       lsb = data[0] & 0xff;
-       msb = (data[0] >> 8) & 0xf;
-
        chan = CR_CHAN(insn->chanspec);
 
        for (n = 0; n < insn->n; n++) {
+               lsb = data[n] & 0xff;
+               msb = (data[n] >> 8) & 0xf;
 #if 0
                outb(lsb, dev->iobase + devpriv->ao_offset_lsb[chan]);
                outb(msb, dev->iobase + devpriv->ao_offset_msb[chan]);
@@ -675,12 +674,11 @@ static int das08ao_ao_winsn(comedi_device * dev, comedi_subdevice * s,
        int lsb, msb;
        int chan;
 
-       lsb = data[0] & 0xff;
-       msb = (data[0] >> 8) & 0xf;
-
        chan = CR_CHAN(insn->chanspec);
 
        for (n = 0; n < insn->n; n++) {
+               lsb = data[n] & 0xff;
+               msb = (data[n] >> 8) & 0xf;
 #if 0
                outb(lsb, dev->iobase + devpriv->ao_offset_lsb[chan]);
                outb(msb, dev->iobase + devpriv->ao_offset_msb[chan]);
@@ -787,6 +785,9 @@ static int das08_counter_read(comedi_device * dev, comedi_subdevice * s,
 {
        int chan = insn->chanspec;
 
+       if (insn->n == 0)
+               return 0;
+
        //printk("Reading counter channel %d ",chan);
        data[0] = i8254_read_channel(&devpriv->i8254, chan);
        //printk("=> 0x%08X\n",data[0]);
@@ -799,6 +800,9 @@ static int das08_counter_write(comedi_device * dev, comedi_subdevice * s,
 {
        int chan = insn->chanspec;
 
+       if (insn->n == 0)
+               return 0;
+
        //printk("Writing counter channel %d with 0x%04X\n",chan,data[0]);
        i8254_write_channel(&devpriv->i8254, chan, data[0]);