| Message ID | 20201002154219.4887-6-mailhol.vincent@wanadoo.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | can: add support for ETAS ES58X CAN USB | expand |
On 10/2/20 5:41 PM, Vincent Mailhol wrote: > Rename macro CAN_CALC_SYNC_SEG to CAN_SYNC_SEG and make it available > through include/linux/can/dev.h > > Add an helper function can_bit_time() which returns the duration (in > time quanta) of one CAN bit. > > Rationale for this patch: the sync segment and the bit time are two > concepts which are defined in the CAN ISO standard. Device drivers for > CAN might need those. > > Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for > additional information. > > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > --- > > Changes in v3: None > > Changes in v2: None > --- > drivers/net/can/dev.c | 13 ++++++------- > include/linux/can/dev.h | 15 +++++++++++++++ > 2 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c > index 8c3e11820e03..6070b4ab3bd8 100644 > --- a/drivers/net/can/dev.c > +++ b/drivers/net/can/dev.c > @@ -60,7 +60,6 @@ EXPORT_SYMBOL_GPL(can_len2dlc); > > #ifdef CONFIG_CAN_CALC_BITTIMING > #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */ > -#define CAN_CALC_SYNC_SEG 1 > > /* Bit-timing calculation derived from: > * > @@ -86,8 +85,8 @@ can_update_sample_point(const struct can_bittiming_const *btc, > int i; > > for (i = 0; i <= 1; i++) { > - tseg2 = tseg + CAN_CALC_SYNC_SEG - > - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / > + tseg2 = tseg + CAN_SYNC_SEG - > + (sample_point_nominal * (tseg + CAN_SYNC_SEG)) / > 1000 - i; > tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max); > tseg1 = tseg - tseg2; > @@ -96,8 +95,8 @@ can_update_sample_point(const struct can_bittiming_const *btc, > tseg2 = tseg - tseg1; > } > > - sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / > - (tseg + CAN_CALC_SYNC_SEG); > + sample_point = 1000 * (tseg + CAN_SYNC_SEG - tseg2) / > + (tseg + CAN_SYNC_SEG); > sample_point_error = abs(sample_point_nominal - sample_point); > > if (sample_point <= sample_point_nominal && > @@ -145,7 +144,7 @@ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, > /* tseg even = round down, odd = round up */ > for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1; > tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) { > - tsegall = CAN_CALC_SYNC_SEG + tseg / 2; > + tsegall = CAN_SYNC_SEG + tseg / 2; > > /* Compute all possible tseg choices (tseg=tseg1+tseg2) */ > brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2; > @@ -223,7 +222,7 @@ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, > > /* real bitrate */ > bt->bitrate = priv->clock.freq / > - (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2)); > + (bt->brp * (CAN_SYNC_SEG + tseg1 + tseg2)); > > return 0; > } > diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h > index 791c452d98e1..77c3ea49b8fb 100644 > --- a/include/linux/can/dev.h > +++ b/include/linux/can/dev.h > @@ -82,6 +82,21 @@ struct can_priv { > #endif > }; > > +#define CAN_SYNC_SEG 1 > + > +/* > + * can_bit_time() - Duration of one bit > + * > + * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for > + * additional information. > + * > + * Return: the number of time quanta in one bit. > + */ > +static inline int can_bit_time(struct can_bittiming *bt) make it return an unsigned int make the bt pointer const > +{ > + return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2; > +} > + > /* > * get_can_dlc(value) - helper macro to cast a given data length code (dlc) > * to u8 and ensure the dlc value to be max. 8 bytes. > tnx, Marc
On 10/4/20 1:06 PM, Marc Kleine-Budde wrote: > On 10/2/20 5:41 PM, Vincent Mailhol wrote: >> Rename macro CAN_CALC_SYNC_SEG to CAN_SYNC_SEG and make it available >> through include/linux/can/dev.h >> >> Add an helper function can_bit_time() which returns the duration (in >> time quanta) of one CAN bit. >> >> Rationale for this patch: the sync segment and the bit time are two >> concepts which are defined in the CAN ISO standard. Device drivers for >> CAN might need those. >> >> Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for >> additional information. >> >> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> [...] >> index 791c452d98e1..77c3ea49b8fb 100644 >> --- a/include/linux/can/dev.h >> +++ b/include/linux/can/dev.h >> @@ -82,6 +82,21 @@ struct can_priv { >> #endif >> }; >> >> +#define CAN_SYNC_SEG 1 >> + >> +/* >> + * can_bit_time() - Duration of one bit >> + * >> + * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for >> + * additional information. >> + * >> + * Return: the number of time quanta in one bit. >> + */ >> +static inline int can_bit_time(struct can_bittiming *bt) > > make it return an unsigned int > make the bt pointer const I'll change this while applying the patch. Marc
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c index 8c3e11820e03..6070b4ab3bd8 100644 --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -60,7 +60,6 @@ EXPORT_SYMBOL_GPL(can_len2dlc); #ifdef CONFIG_CAN_CALC_BITTIMING #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */ -#define CAN_CALC_SYNC_SEG 1 /* Bit-timing calculation derived from: * @@ -86,8 +85,8 @@ can_update_sample_point(const struct can_bittiming_const *btc, int i; for (i = 0; i <= 1; i++) { - tseg2 = tseg + CAN_CALC_SYNC_SEG - - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / + tseg2 = tseg + CAN_SYNC_SEG - + (sample_point_nominal * (tseg + CAN_SYNC_SEG)) / 1000 - i; tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max); tseg1 = tseg - tseg2; @@ -96,8 +95,8 @@ can_update_sample_point(const struct can_bittiming_const *btc, tseg2 = tseg - tseg1; } - sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / - (tseg + CAN_CALC_SYNC_SEG); + sample_point = 1000 * (tseg + CAN_SYNC_SEG - tseg2) / + (tseg + CAN_SYNC_SEG); sample_point_error = abs(sample_point_nominal - sample_point); if (sample_point <= sample_point_nominal && @@ -145,7 +144,7 @@ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, /* tseg even = round down, odd = round up */ for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1; tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) { - tsegall = CAN_CALC_SYNC_SEG + tseg / 2; + tsegall = CAN_SYNC_SEG + tseg / 2; /* Compute all possible tseg choices (tseg=tseg1+tseg2) */ brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2; @@ -223,7 +222,7 @@ static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt, /* real bitrate */ bt->bitrate = priv->clock.freq / - (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2)); + (bt->brp * (CAN_SYNC_SEG + tseg1 + tseg2)); return 0; } diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 791c452d98e1..77c3ea49b8fb 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -82,6 +82,21 @@ struct can_priv { #endif }; +#define CAN_SYNC_SEG 1 + +/* + * can_bit_time() - Duration of one bit + * + * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for + * additional information. + * + * Return: the number of time quanta in one bit. + */ +static inline int can_bit_time(struct can_bittiming *bt) +{ + return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2; +} + /* * get_can_dlc(value) - helper macro to cast a given data length code (dlc) * to u8 and ensure the dlc value to be max. 8 bytes.
Rename macro CAN_CALC_SYNC_SEG to CAN_SYNC_SEG and make it available through include/linux/can/dev.h Add an helper function can_bit_time() which returns the duration (in time quanta) of one CAN bit. Rationale for this patch: the sync segment and the bit time are two concepts which are defined in the CAN ISO standard. Device drivers for CAN might need those. Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for additional information. Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> --- Changes in v3: None Changes in v2: None --- drivers/net/can/dev.c | 13 ++++++------- include/linux/can/dev.h | 15 +++++++++++++++ 2 files changed, 21 insertions(+), 7 deletions(-)