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authorVincent Mailhol <mailhol.vincent@wanadoo.fr>2020-10-02 18:41:49 +0300
committerMarc Kleine-Budde <mkl@pengutronix.de>2020-10-08 00:17:45 +0300
commit1c47fa6b31c2683f03bc2f9174902bb7dcd35d83 (patch)
tree6b23951a7d08219521f24875aaa6fc1f843f6bb3 /include/linux/can/dev.h
parentf55a52bb2cdbc5a92ca209d0ada90a490a188f58 (diff)
downloadlinux-1c47fa6b31c2683f03bc2f9174902bb7dcd35d83.tar.xz
can: dev: add a helper function to calculate the duration of one bit
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> Link: https://lore.kernel.org/r/20201002154219.4887-6-mailhol.vincent@wanadoo.fr [mkl: Let can_bit_time() return an unsinged int, make argument const] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'include/linux/can/dev.h')
-rw-r--r--include/linux/can/dev.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index f8975d0b90bb..41ff31795320 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 unsigned int can_bit_time(const 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.