diff options
Diffstat (limited to 'include/linux/can/bittiming.h')
| -rw-r--r-- | include/linux/can/bittiming.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h index 6572ec1712ca..4d5f7794194a 100644 --- a/include/linux/can/bittiming.h +++ b/include/linux/can/bittiming.h @@ -161,6 +161,35 @@ int can_get_bittiming(const struct net_device *dev, struct can_bittiming *bt, struct netlink_ext_ack *extack); /* + * can_get_relative_tdco() - TDCO relative to the sample point + * + * struct can_tdc::tdco represents the absolute offset from TDCV. Some + * controllers use instead an offset relative to the Sample Point (SP) + * such that: + * + * SSP = TDCV + absolute TDCO + * = TDCV + SP + relative TDCO + * + * -+----------- one bit ----------+-- TX pin + * |<--- Sample Point --->| + * + * --+----------- one bit ----------+-- RX pin + * |<-------- TDCV -------->| + * |<------------------------>| absolute TDCO + * |<--- Sample Point --->| + * | |<->| relative TDCO + * |<------------- Secondary Sample Point ------------>| + */ +static inline s32 can_get_relative_tdco(const struct data_bittiming_params *dbt_params) +{ + const struct can_bittiming *dbt = &dbt_params->data_bittiming; + s32 sample_point_in_tc = (CAN_SYNC_SEG + dbt->prop_seg + + dbt->phase_seg1) * dbt->brp; + + return (s32)dbt_params->tdc.tdco - sample_point_in_tc; +} + +/* * can_bit_time() - Duration of one bit * * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for |