staging: comedi: ni_mio_common: tidy up AO scan begin

The (*do_cmdtest) validates that the cmd->scan_begin_src will only be
TRIG_TIMER or TRIG_EXT. Refactor ni_ao_cmd_set_update() and remove the
BUG() which can never occur.

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_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index c89bd1fbffeeaf76cc42c395a4501d8e4f4e88cb..1e2e89fccb5bac92db72626cc3ce8bdd22bb6238 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -3099,8 +3099,9 @@ static void ni_ao_cmd_set_update(struct comedi_device *dev,
          NISTC_AO_MODE1_UPDATE_SRC_POLARITY
        );
 
-       switch (cmd->scan_begin_src) {
-       case TRIG_TIMER:
+       if (cmd->scan_begin_src == TRIG_TIMER) {
+               unsigned int trigvar;
+
                devpriv->ao_cmd2  &= ~NISTC_AO_CMD2_BC_GATE_ENA;
 
                /*
@@ -3131,35 +3132,25 @@ static void ni_ao_cmd_set_update(struct comedi_device *dev,
                 * eseries/ni67xx and tMSeries.h for mseries.
                 */
 
-               {
-                       unsigned int trigvar;
-
-                       trigvar = ni_ns_to_timer(dev, cmd->scan_begin_arg,
-                                                CMDF_ROUND_NEAREST);
+               trigvar = ni_ns_to_timer(dev, cmd->scan_begin_arg,
+                                        CMDF_ROUND_NEAREST);
 
-                       /*
-                        * Wait N TB3 ticks after the start trigger before
-                        * clocking(N must be >=2).
-                        */
-                       /* following line: 2-1 per STC */
-                       ni_stc_writel(dev, 1,           NISTC_AO_UI_LOADA_REG);
-                       ni_stc_writew(dev, NISTC_AO_CMD1_UI_LOAD,
-                                     NISTC_AO_CMD1_REG);
-                       /* following line: N-1 per STC */
-                       ni_stc_writel(dev, trigvar - 1, NISTC_AO_UI_LOADA_REG);
-               }
-               break;
-       case TRIG_EXT:
+               /*
+                * Wait N TB3 ticks after the start trigger before
+                * clocking (N must be >=2).
+                */
+               /* following line: 2-1 per STC */
+               ni_stc_writel(dev, 1, NISTC_AO_UI_LOADA_REG);
+               ni_stc_writew(dev, NISTC_AO_CMD1_UI_LOAD, NISTC_AO_CMD1_REG);
+               /* following line: N-1 per STC */
+               ni_stc_writel(dev, trigvar - 1, NISTC_AO_UI_LOADA_REG);
+       } else { /* TRIG_EXT */
                /* FIXME:  assert scan_begin_arg != 0, ret failure otherwise */
                devpriv->ao_cmd2  |= NISTC_AO_CMD2_BC_GATE_ENA;
                devpriv->ao_mode1 |= NISTC_AO_MODE1_UPDATE_SRC(
                                        CR_CHAN(cmd->scan_begin_arg));
                if (cmd->scan_begin_arg & CR_INVERT)
                        devpriv->ao_mode1 |= NISTC_AO_MODE1_UPDATE_SRC_POLARITY;
-               break;
-       default:
-               BUG();
-               break;
        }
 
        ni_stc_writew(dev, devpriv->ao_cmd2, NISTC_AO_CMD2_REG);