staging: comedi: adl_pci7x3x: fix digital output on PCI-7230

The "adl_pci7x3x" driver replaced the "adl_pci7230" and "adl_pci7432"
drivers in commits 8f567c373c4b ("staging: comedi: new adl_pci7x3x
driver") and 657f77d173d3 ("staging: comedi: remove adl_pci7230 and
adl_pci7432 drivers").  Although the new driver code agrees with the
user manuals for the respective boards, digital outputs stopped working
on the PCI-7230.  This has 16 digital output channels and the previous
adl_pci7230 driver shifted the 16 bit output state left by 16 bits
before writing to the hardware register.  The new adl_pci7x3x driver
doesn't do that.  Fix it in `adl_pci7x3x_do_insn_bits()` by checking
for the special case of the subdevice having only 16 channels and
duplicating the 16 bit output state into both halves of the 32-bit
register.  That should work both for what the board actually does and
for what the user manual says it should do.

Fixes: 8f567c373c4b ("staging: comedi: new adl_pci7x3x driver")
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: <stable@vger.kernel.org> # 3.13+, needs backporting for 3.7 to 3.12
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/adl_pci7x3x.c b/drivers/staging/comedi/drivers/adl_pci7x3x.c
index 934af3ff789732f4aeb4928997e72318ad609f7b..b0fc027cf485d11cebdb6d495bbce59e239c9996 100644 (file)
--- a/drivers/staging/comedi/drivers/adl_pci7x3x.c
+++ b/drivers/staging/comedi/drivers/adl_pci7x3x.c
@@ -120,8 +120,20 @@ static int adl_pci7x3x_do_insn_bits(struct comedi_device *dev,
 {
        unsigned long reg = (unsigned long)s->private;
 
-       if (comedi_dio_update_state(s, data))
-               outl(s->state, dev->iobase + reg);
+       if (comedi_dio_update_state(s, data)) {
+               unsigned int val = s->state;
+
+               if (s->n_chan == 16) {
+                       /*
+                        * It seems the PCI-7230 needs the 16-bit DO state
+                        * to be shifted left by 16 bits before being written
+                        * to the 32-bit register.  Set the value in both
+                        * halves of the register to be sure.
+                        */
+                       val |= val << 16;
+               }
+               outl(val, dev->iobase + reg);
+       }
 
        data[1] = s->state;