staging: comedi: ni_65xx: cleanup INSN_CONFIG_FILTER handling

The INSN_CONFIG_FILTER instruction is used to set the deglitch filter
interval used to debounce the input channels.

Absorb the helper function into the (*insn_config) function and refactor
the code to not require the 'filter_interval' and 'filter_enable' members
in the private data.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_65xx.c b/drivers/staging/comedi/drivers/ni_65xx.c
index 83e41440153893ae96576a8ed4c65eaaeeeb9dab..c8cd0e1dcc66e658c52d3a081a44338a6d3ebd13 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_65xx.c
+++ b/drivers/staging/comedi/drivers/ni_65xx.c
@@ -271,8 +271,6 @@ static inline unsigned ni_65xx_total_num_ports(const struct ni_65xx_board
 
 struct ni_65xx_private {
        void __iomem *mmio;
-       unsigned int filter_interval;
-       unsigned short filter_enable[NI_65XX_MAX_NUM_PORTS];
        unsigned short output_bits[NI_65XX_MAX_NUM_PORTS];
        unsigned short dio_direction[NI_65XX_MAX_NUM_PORTS];
 };
@@ -287,60 +285,46 @@ static inline struct ni_65xx_subdevice_private *sprivate(struct comedi_subdevice
        return subdev->private;
 }
 
-static int ni_65xx_config_filter(struct comedi_device *dev,
-                                struct comedi_subdevice *s,
-                                struct comedi_insn *insn, unsigned int *data)
-{
-       struct ni_65xx_private *devpriv = dev->private;
-       const unsigned chan = CR_CHAN(insn->chanspec);
-       const unsigned port =
-           sprivate(s)->base_port + ni_65xx_port_by_channel(chan);
-
-       if (data[0] != INSN_CONFIG_FILTER)
-               return -EINVAL;
-       if (data[1]) {
-               static const unsigned filter_resolution_ns = 200;
-               static const unsigned max_filter_interval = 0xfffff;
-               unsigned interval =
-                   (data[1] +
-                    (filter_resolution_ns / 2)) / filter_resolution_ns;
-               if (interval > max_filter_interval)
-                       interval = max_filter_interval;
-               data[1] = interval * filter_resolution_ns;
-
-               if (interval != devpriv->filter_interval) {
-                       writel(interval, devpriv->mmio + NI_65XX_FILTER_REG);
-                       devpriv->filter_interval = interval;
-               }
-
-               devpriv->filter_enable[port] |=
-                   1 << (chan % ni_65xx_channels_per_port);
-       } else {
-               devpriv->filter_enable[port] &=
-                   ~(1 << (chan % ni_65xx_channels_per_port));
-       }
-
-       writeb(devpriv->filter_enable[port],
-              devpriv->mmio + NI_65XX_FILTER_ENA(port));
-
-       return 2;
-}
-
 static int ni_65xx_dio_insn_config(struct comedi_device *dev,
                                   struct comedi_subdevice *s,
-                                  struct comedi_insn *insn, unsigned int *data)
+                                  struct comedi_insn *insn,
+                                  unsigned int *data)
 {
        struct ni_65xx_private *devpriv = dev->private;
-       unsigned port;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int chan_mask = 1 << (chan % ni_65xx_channels_per_port);
+       unsigned port = sprivate(s)->base_port + ni_65xx_port_by_channel(chan);
+       unsigned int interval;
+       unsigned int val;
 
-       if (insn->n < 1)
-               return -EINVAL;
-       port = sprivate(s)->base_port +
-           ni_65xx_port_by_channel(CR_CHAN(insn->chanspec));
        switch (data[0]) {
        case INSN_CONFIG_FILTER:
-               return ni_65xx_config_filter(dev, s, insn, data);
-               break;
+               /*
+                * The deglitch filter interval is specified in nanoseconds.
+                * The hardware supports intervals in 200ns increments. Round
+                * the user values up and return the actual interval.
+                */
+               interval = (data[1] + 100) / 200;
+               if (interval > 0xfffff)
+                       interval = 0xfffff;
+               data[1] = interval * 200;
+
+               /*
+                * Enable/disable the channel for deglitch filtering. Note
+                * that the filter interval is never set to '0'. This is done
+                * because other channels might still be enabled for filtering.
+                */
+               val = readb(devpriv->mmio + NI_65XX_FILTER_ENA(port));
+               if (interval) {
+                       writel(interval, devpriv->mmio + NI_65XX_FILTER_REG);
+                       val |= chan_mask;
+               } else {
+                       val &= ~chan_mask;
+               }
+               writeb(val, devpriv->mmio + NI_65XX_FILTER_ENA(port));
+
+               return insn->n;
+
        case INSN_CONFIG_DIO_OUTPUT:
                if (s->type != COMEDI_SUBD_DIO)
                        return -EINVAL;