staging: comedi: ni_6527: support INSN_CONFIG_DIGITAL_TRIG

The "edge detection interrupt" subdevice supports the
`INSN_CONFIG_CHANGE_NOTIFY` comedi instruction which is only supported
by one other driver.  The `INSN_CONFIG_DIGITAL_TRIG` comedi instruction
is more flexible as it supports both edge and level detection, but is
not currently supported by this driver.

Add partial support for `INSN_CONFIG_DIGITAL_TRIG`, but only for edge
detection.  Make use of the `ni6527_set_edge_detection()` used for
`INSN_CONFIG_CHANGE_NOTIFY`, but add a parameter holding a mask of the
rising and falling edges to be updated and preserve the unmasked edges
when updating.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_6527.c b/drivers/staging/comedi/drivers/ni_6527.c
index c8b1fa7..57d8d4c 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_6527.c
+++ b/drivers/staging/comedi/drivers/ni_6527.c
@@ -299,21 +299,38 @@ static int ni6527_intr_insn_bits(struct comedi_device *dev,
 }
 
 static void ni6527_set_edge_detection(struct comedi_device *dev,
+                                     unsigned int mask,
                                      unsigned int rising,
                                      unsigned int falling)
 {
        struct ni6527_private *devpriv = dev->private;
        void __iomem *mmio = devpriv->mmio_base;
-
-       /* enable rising-edge detection channels */
-       writeb(rising & 0xff, mmio + NI6527_RISING_EDGE_REG(0));
-       writeb((rising >> 8) & 0xff, mmio + NI6527_RISING_EDGE_REG(1));
-       writeb((rising >> 16) & 0xff, mmio + NI6527_RISING_EDGE_REG(2));
-
-       /* enable falling-edge detection channels */
-       writeb(falling & 0xff, mmio + NI6527_FALLING_EDGE_REG(0));
-       writeb((falling >> 8) & 0xff, mmio + NI6527_FALLING_EDGE_REG(1));
-       writeb((falling >> 16) & 0xff, mmio + NI6527_FALLING_EDGE_REG(2));
+       unsigned int i;
+
+       rising &= mask;
+       falling &= mask;
+       for (i = 0; i < 2; i++) {
+               if (mask & 0xff) {
+                       if (~mask & 0xff) {
+                               /* preserve rising-edge detection channels */
+                               rising |= readb(mmio +
+                                               NI6527_RISING_EDGE_REG(i)) &
+                                         (~mask & 0xff);
+                               /* preserve falling-edge detection channels */
+                               falling |= readb(mmio +
+                                                NI6527_FALLING_EDGE_REG(i)) &
+                                          (~mask & 0xff);
+                       }
+                       /* update rising-edge detection channels */
+                       writeb(rising & 0xff, mmio + NI6527_RISING_EDGE_REG(i));
+                       /* update falling-edge detection channels */
+                       writeb(falling & 0xff,
+                              mmio + NI6527_FALLING_EDGE_REG(i));
+               }
+               rising >>= 8;
+               falling >>= 8;
+               mask >>= 8;
+       }
 }
 
 static int ni6527_intr_insn_config(struct comedi_device *dev,
@@ -321,12 +338,45 @@ static int ni6527_intr_insn_config(struct comedi_device *dev,
                                   struct comedi_insn *insn,
                                   unsigned int *data)
 {
+       unsigned int mask = 0xffffffff;
+       unsigned int rising, falling, shift;
+
        switch (data[0]) {
        case INSN_CONFIG_CHANGE_NOTIFY:
                /* check_insn_config_length() does not check this instruction */
                if (insn->n != 3)
                        return -EINVAL;
-               ni6527_set_edge_detection(dev, data[1], data[2]);
+               rising = data[1];
+               falling = data[2];
+               ni6527_set_edge_detection(dev, mask, rising, falling);
+               break;
+       case INSN_CONFIG_DIGITAL_TRIG:
+               /* check trigger number */
+               if (data[1] != 0)
+                       return -EINVAL;
+               /* check digital trigger operation */
+               switch (data[2]) {
+               case COMEDI_DIGITAL_TRIG_DISABLE:
+                       rising = 0;
+                       falling = 0;
+                       break;
+               case COMEDI_DIGITAL_TRIG_ENABLE_EDGES:
+                       /* check shift amount */
+                       shift = data[3];
+                       if (shift >= s->n_chan) {
+                               mask = 0;
+                               rising = 0;
+                               falling = 0;
+                       } else {
+                               mask <<= shift;
+                               rising = data[4] << shift;
+                               falling = data[5] << shift;
+                       }
+                       break;
+               default:
+                       return -EINVAL;
+               }
+               ni6527_set_edge_detection(dev, mask, rising, falling);
                break;
        default:
                return -EINVAL;