staging: comedi: c6xdigio: tidy up c6xdigio_pwm_write()

The 10-bit pwm value (2-498) is written by banging 2-bits in the data register.

Refactor this function to remove the need for the union pcmcmdtype and struct
pwmbitstype.

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/c6xdigio.c b/drivers/staging/comedi/drivers/c6xdigio.c
index 7c2c19f..a9066d6 100644 (file)
--- a/drivers/staging/comedi/drivers/c6xdigio.c
+++ b/drivers/staging/comedi/drivers/c6xdigio.c
@@ -50,18 +50,6 @@ http://robot0.ge.uiuc.edu/~spong/mecha/
 #define C6XDIGIO_STATUS_REG    0x01
 #define C6XDIGIO_CTRL_REG      0x02
 
-struct pwmbitstype {
-       unsigned sb0:2;
-       unsigned sb1:2;
-       unsigned sb2:2;
-       unsigned sb3:2;
-       unsigned sb4:2;
-};
-union pwmcmdtype {
-       unsigned cmd;           /*  assuming here that int is 32bit */
-       struct pwmbitstype bits;
-};
-
 #define C6XDIGIO_TIME_OUT 20
 
 static int c6xdigio_chk_status(struct comedi_device *dev, unsigned long context)
@@ -113,25 +101,30 @@ static void c6xdigio_pwm_init(struct comedi_device *dev)
 static void c6xdigio_pwm_write(struct comedi_device *dev,
                               unsigned int chan, unsigned int val)
 {
+       unsigned int bits;
        unsigned ppcmd;
-       union pwmcmdtype pwm;
-
-       pwm.cmd = val;
-       if (pwm.cmd > 498)
-               pwm.cmd = 498;
-       if (pwm.cmd < 2)
-               pwm.cmd = 2;
 
        if (chan == 0)
                ppcmd = 0x28;
        else
                ppcmd = 0x30;
 
-       c6xdigio_write_data(dev, ppcmd + pwm.bits.sb0, 0x00);
-       c6xdigio_write_data(dev, ppcmd + pwm.bits.sb1 + 0x4, 0x80);
-       c6xdigio_write_data(dev, ppcmd + pwm.bits.sb2, 0x00);
-       c6xdigio_write_data(dev, ppcmd + pwm.bits.sb3 + 0x4, 0x80);
-       c6xdigio_write_data(dev, ppcmd + pwm.bits.sb4, 0x00);
+       if (val > 498)
+               val = 498;
+       if (val < 2)
+               val = 2;
+
+       bits = (val >> 0) & 0x03;
+       c6xdigio_write_data(dev, ppcmd + bits, 0x00);
+       bits = (val >> 2) & 0x03;
+       c6xdigio_write_data(dev, ppcmd + bits + 0x4, 0x80);
+       bits = (val >> 4) & 0x03;
+       c6xdigio_write_data(dev, ppcmd + bits, 0x00);
+       bits = (val >> 6) & 0x03;
+       c6xdigio_write_data(dev, ppcmd + bits + 0x4, 0x80);
+       bits = (val >> 8) & 0x03;
+       c6xdigio_write_data(dev, ppcmd + bits, 0x00);
+
        c6xdigio_write_data(dev, 0x00, 0x80);
 }