diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2013-10-18 14:40:49 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-19 13:47:23 -0700 |
| commit | 6c661434f98dfe0ad301a4910b6209b0541c0239 (patch) | |
| tree | 0d317f21046b71246b5d4406b2db01fa23998e42 | |
| parent | f8d939e411f57a5facdfba66be2404f5ed238e30 (diff) | |
staging: comedi: s626: clock polarity and direction are the same
When setting up an encoder channel, the setup value includes a polarity
and direction, but these are the same bit of the setup value:
S626_CLKPOL_POS = S626_CNTDIR_UP = 0
S626_CLKPOL_NEG = S626_CNTDIR_DOWN = 1
In the construction of the setup value, both the CLKPOL and the CNTDIR
constants are shifted by the same amount `S626_BF_CLKPOL`. Only the
following combinations are set up currently (this may change if user
configuration of the encoder is implemented properly):
(S626_CLKPOL_POS << S626_BF_CLKPOL)
(S626_CLKPOL_POS << S626_BF_CLKPOL) |
(S626_CNTDIR_UP << S626_BF_CLKPOL)
(S626_CLKPOL_POS << S626_BF_CLKPOL) |
(S626_CNTDIR_DOWN << S626_BF_CLKPOL)
The first two are used in "counter" mode and is equivalent to:
(S626_CLKPOL_POS << S626_BF_CLKPOL)
The last one is used in "timer" mode and is equivalent to:
(S626_CNTDIR_DOWN << S626_BF_CLKPOL)
Use the shorter equivalents. The comments in "s626.h" indicate that the
'CLKPOL' constants make more sense for the "counter" mode (when the
encoders operate as up/down counters) and the 'CNTDIR' constants make
more sense for the "timer" mode.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers/s626.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/staging/comedi/drivers/s626.c b/drivers/staging/comedi/drivers/s626.c index d9aba7ce862d..dd138a095624 100644 --- a/drivers/staging/comedi/drivers/s626.c +++ b/drivers/staging/comedi/drivers/s626.c @@ -2036,8 +2036,6 @@ static void s626_timer_load(struct comedi_device *dev, (S626_INDXSRC_SOFT << S626_BF_INDXSRC) | /* Operating mode is Timer. */ (S626_CLKSRC_TIMER << S626_BF_CLKSRC) | - /* Active high clock. */ - (S626_CLKPOL_POS << S626_BF_CLKPOL) | /* Count direction is Down. */ (S626_CNTDIR_DOWN << S626_BF_CLKPOL) | /* Clock multiplier is 1x. */ @@ -2528,8 +2526,6 @@ static void s626_counters_init(struct comedi_device *dev) (S626_CLKSRC_COUNTER << S626_BF_CLKSRC) | /* Active high clock. */ (S626_CLKPOL_POS << S626_BF_CLKPOL) | - /* Count direction is up. */ - (S626_CNTDIR_UP << S626_BF_CLKPOL) | /* Clock multiplier is 1x. */ (S626_CLKMULT_1X << S626_BF_CLKMULT) | /* Enabled by index */ |