[PATCH 08/11] staging: comedi: s626: make CRA and CRB setup conversions more readable
Ian Abbott
abbotti at mev.co.uk
Sat Oct 19 23:43:36 UTC 2013
On 18/10/13 19:24, Hartley Sweeten wrote:
> On Friday, October 18, 2013 6:41 AM, Ian Abbott wrote:
>> Use the new macros defined in "s626.h" for constructing and decomposing
>> 'CRA', 'CRB' and standardized encoder setup values to make the
>> conversions between standardized encoder setup values, and CRA/CRB
>> register values easier to follow.
>>
>> There is some messing about with the 'IndxSrc' values which are 1-bit
>> wide in the standardized encoder setup, and 2-bit wide in the 'CRA' and
>> 'CRB' register values. This will be addressed by a later patch.
>>
>> Signed-off-by: Ian Abbott <abbotti at mev.co.uk>
>> ---
>> drivers/staging/comedi/drivers/s626.c | 317 ++++++++++++++++------------------
>> 1 file changed, 151 insertions(+), 166 deletions(-)
>>
>> diff --git a/drivers/staging/comedi/drivers/s626.c b/drivers/staging/comedi/drivers/s626.c
>> index 92062ed..ce320b3 100644
>> --- a/drivers/staging/comedi/drivers/s626.c
>> +++ b/drivers/staging/comedi/drivers/s626.c
>
> [snip]
>
>> @@ -765,50 +766,46 @@ static uint16_t s626_get_mode_b(struct comedi_device *dev,
>> * Populate the standardized counter setup bit fields.
>> * Note: IndexSrc is restricted to ENC_X or IndxPol.
>> */
>> - setup = ((crb << (S626_STDBIT_INTSRC - S626_CRBBIT_INTSRC_B)) &
>> - S626_STDMSK_INTSRC) | /* IntSrc = IntSrcB. */
>> - ((crb << (S626_STDBIT_LATCHSRC - S626_CRBBIT_LATCHSRC)) &
>> - S626_STDMSK_LATCHSRC) | /* LatchSrc = LatchSrcB. */
>> - ((crb << (S626_STDBIT_LOADSRC - S626_CRBBIT_LOADSRC_B)) &
>> - S626_STDMSK_LOADSRC) | /* LoadSrc = LoadSrcB. */
>> - ((crb << (S626_STDBIT_INDXPOL - S626_CRBBIT_INDXPOL_B)) &
>> - S626_STDMSK_INDXPOL) | /* IndxPol = IndxPolB. */
>> - ((crb >> (S626_CRBBIT_CLKENAB_B - S626_STDBIT_CLKENAB)) &
>> - S626_STDMSK_CLKENAB) | /* ClkEnab = ClkEnabB. */
>> - ((cra >> ((S626_CRABIT_INDXSRC_B + 1) - S626_STDBIT_INDXSRC)) &
>> - S626_STDMSK_INDXSRC); /* IndxSrc = IndxSrcB<1>. */
>> + setup =
>> + /* IntSrc = IntSrcB. */
>> + S626_SET_STD_INTSRC(S626_GET_CRB_INTSRC_B(crb)) |
>> + /* LatchSrc = LatchSrcB. */
>> + S626_SET_STD_LATCHSRC(S626_GET_CRB_LATCHSRC(crb)) |
>> + /* LoadSrc = LoadSrcB. */
>> + S626_SET_STD_LOADSRC(S626_GET_CRB_LOADSRC_B(crb)) |
>> + /* IndxPol = IndxPolB. */
>> + S626_SET_STD_INDXPOL(S626_GET_CRB_INDXPOL_B(crb)) |
>> + /* ClkEnab = ClkEnabB. */
>> + S626_SET_STD_CLKENAB(S626_GET_CRB_CLKENAB_B(crb)) |
>> + /* IndxSrc = IndxSrcB<1>. */
>> + S626_SET_STD_INDXSRC(S626_GET_CRA_INDXSRC_B(cra) >> 1);
>>
>> /* Adjust mode-dependent parameters. */
>> - if ((crb & S626_CRBMSK_CLKMULT_B) ==
>> - (S626_MULT_X0 << S626_CRBBIT_CLKMULT_B)) {
>> + cntsrc = S626_GET_CRA_CNTSRC_B(cra);
>> + clkmult = S626_GET_CRB_CLKMULT_B(crb);
>> + if (clkmult == S626_MULT_X0) {
>> /* Extender mode (ClkMultB == S626_MULT_X0): */
>> - /* Indicate Extender mode. */
>> - setup |= S626_ENCMODE_EXTENDER << S626_STDBIT_ENCMODE;
>> + encmode = S626_ENCMODE_EXTENDER;
>> /* Indicate multiplier is 1x. */
>> - setup |= S626_MULT_X1 << S626_STDBIT_CLKMULT;
>> + clkmult = S626_MULT_X1;
>> /* Set ClkPol equal to Timer count direction (CntSrcB<0>). */
>> - setup |= (cra >> (S626_CRABIT_CNTSRC_B - S626_STDBIT_CLKPOL)) &
>> - S626_STDMSK_CLKPOL;
>> - } else if (cra & (S626_CNTSRC_SYSCLK << S626_CRABIT_CNTSRC_B)) {
>> + clkpol = cntsrc & 1;
>> + } else if (cntsrc & S626_CNTSRC_SYSCLK) {
>> /* Timer mode (CntSrcB<1> == 1): */
>> - /* Indicate Timer mode. */
>> - setup |= S626_ENCMODE_TIMER << S626_STDBIT_ENCMODE;
>> + encmode = S626_ENCMODE_TIMER;
>> /* Indicate multiplier is 1x. */
>> - setup |= S626_MULT_X1 << S626_STDBIT_CLKMULT;
>> + clkmult = S626_MULT_X1;
>> /* Set ClkPol equal to Timer count direction (CntSrcB<0>). */
>> - setup |= (cra >> (S626_CRABIT_CNTSRC_B - S626_STDBIT_CLKPOL)) &
>> - S626_STDMSK_CLKPOL;
>> + setup |= S626_SET_STD_CLKPOL(cntsrc & 1);
>
> Oops missed this.
>
> Based on the other changes I think you want this one to be:
>
> clkpol = cntsrc & 1;
>
> [snip]
>
>> + setup |= S626_SET_STD_ENCMODE(encmode) | S626_SET_STD_CLKMULT(clkmult) |
>> + S626_SET_STD_CLKPOL(clkpol);
>
> Otherwise the code above produces this warning:
>
> drivers/staging/comedi/drivers/s626.c: In function 's626_get_mode_b':
> drivers/staging/comedi/drivers/s626.c:805:8: warning: 'clkpol' may be used uninitialized in this function [-Wmaybe-uninitialized]
Well spotted! I don't know how I missed that one. I don't recall seeing
the compiler warning.
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