On 04/07/2025 at 19:12, Biju Das wrote:
> Hi Vincent,
>
> Thanks for the feedback.
>
>> -----Original Message-----
>> From: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
>> Sent: 04 July 2025 03:25
>> Subject: Re: [PATCH 4/4] can: rcar_canfd: Replace RCANFD_CFG_* macros with FIELD_PREP
>>
>> Hi Biju,
>>
>> On 04/07/2025 at 03:34, Biju Das wrote:
>>> Replace RCANFD_CFG_* macros with simpler FIELD_PREP macro.
>>>
>>> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>>> ---
>>> drivers/net/can/rcar/rcar_canfd.c | 10 ++--------
>>> 1 file changed, 2 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
>>> index b5b059e83374..dd87b4e8e688 100644
>>> --- a/drivers/net/can/rcar/rcar_canfd.c
>>> +++ b/drivers/net/can/rcar/rcar_canfd.c
>>> @@ -102,12 +102,6 @@
>>>
>>> /* Channel register bits */
>>>
>>> -/* RSCFDnCmCFG - Classical CAN only */
>>> -#define RCANFD_CFG_SJW(x) (((x) & 0x3) << 24)
>>> -#define RCANFD_CFG_TSEG2(x) (((x) & 0x7) << 20)
>>> -#define RCANFD_CFG_TSEG1(x) (((x) & 0xf) << 16)
>>> -#define RCANFD_CFG_BRP(x) (((x) & 0x3ff) << 0)
>>> -
>>> /* RSCFDnCFDCmCTR / RSCFDnCmCTR */
>>> #define RCANFD_CCTR_CTME BIT(24)
>>> #define RCANFD_CCTR_ERRD BIT(23)
>>> @@ -1418,8 +1412,8 @@ static void rcar_canfd_set_bittiming(struct net_device *ndev)
>>> if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) || gpriv->info->shared_can_regs) {
>>> cfg = rcar_canfd_compute_nominal_bit_rate_cfg(gpriv->info, tseg1, brp, sjw, tseg2);
>>> } else {
>>> - cfg = (RCANFD_CFG_TSEG1(tseg1) | RCANFD_CFG_BRP(brp) |
>>> - RCANFD_CFG_SJW(sjw) | RCANFD_CFG_TSEG2(tseg2));
>>> + cfg = FIELD_PREP(GENMASK(19, 16), tseg1) | FIELD_PREP(GENMASK(9, 0), brp) |
>>> + FIELD_PREP(GENMASK(25, 24), sjw) | FIELD_PREP(GENMASK(22, 20), tseg2);
>>> }
>>
>> You can still keep the macro definition to give a meaning to the magic number:
>>
>> #define RCANFD_CFG_SJW_MASK GENMASK(25, 24)
>>
>> and do a:
>>
>> FIELD_PREP(RCANFD_CFG_SJW_MASK, sjw)
>
> Are you ok for the below change to reduce the changes minimum??
>
> -#define RCANFD_CFG_SJW(x) (((x) & 0x3) << 24)
> +#define RCANFD_CFG_SJW(x) FIELD_PREP(GENMASK(25, 24), x))
No more function-like macro please :)
Normal macro definitions are totally welcome. These allow to attach a name to
otherwise totally meaningless magic numbers.
When it goes to the actual calculation, functions are best.
> Or
>
> you want RCANFD_CFG_SJW_MASK as separate one as you suggested?
This please :)
Yours sincerely,
Vincent Mailhol
