| Message ID | 20210815033248.98111-5-mailhol.vincent@wanadoo.fr (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | add the netlink interface for CAN-FD Transmitter Delay Compensation (TDC) | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 1 maintainers not CCed: wg@grandegger.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 35 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
On 15.08.2021 12:32:45, Vincent Mailhol wrote: > 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 > > Consequently: > | relative TDCO = absolute TDCO - SP > > The function can_tdc_get_relative_tdco() allow to retrieve this > relative TDCO value. > > CC: Stefan Mätje <Stefan.Maetje@esd.eu> > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > --- > include/linux/can/dev.h | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h > index 0be982fd22fb..fa75e29182a3 100644 > --- a/include/linux/can/dev.h > +++ b/include/linux/can/dev.h > @@ -93,6 +93,35 @@ static inline bool can_tdc_is_enabled(const struct can_priv *priv) > return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK); > } > > +/* > + * 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 can_priv *priv) > +{ > + const struct can_bittiming *dbt = &priv->data_bittiming; > + s32 sample_point_in_tc = (CAN_SYNC_SEG + dbt->prop_seg + ^^ Only one space. I'll fix the while applying. > + dbt->phase_seg1) * dbt->brp; > + > + return (s32)priv->tdc.tdco - sample_point_in_tc; > +} > + > /* helper to define static CAN controller features at device creation time */ > static inline void can_set_static_ctrlmode(struct net_device *dev, > u32 static_mode) Marc
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 0be982fd22fb..fa75e29182a3 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -93,6 +93,35 @@ static inline bool can_tdc_is_enabled(const struct can_priv *priv) return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK); } +/* + * 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 can_priv *priv) +{ + const struct can_bittiming *dbt = &priv->data_bittiming; + s32 sample_point_in_tc = (CAN_SYNC_SEG + dbt->prop_seg + + dbt->phase_seg1) * dbt->brp; + + return (s32)priv->tdc.tdco - sample_point_in_tc; +} + /* helper to define static CAN controller features at device creation time */ static inline void can_set_static_ctrlmode(struct net_device *dev, u32 static_mode)
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 Consequently: | relative TDCO = absolute TDCO - SP The function can_tdc_get_relative_tdco() allow to retrieve this relative TDCO value. CC: Stefan Mätje <Stefan.Maetje@esd.eu> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> --- include/linux/can/dev.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)