From: Marc Kleine-Budde <mkl@pengutronix.de>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org,
kernel@pengutronix.de,
"Vincent Mailhol" <mailhol.vincent@wanadoo.fr>,
"Stefan Mätje" <Stefan.Maetje@esd.eu>,
"Marc Kleine-Budde" <mkl@pengutronix.de>
Subject: [PATCH net-next 08/15] can: dev: add can_tdc_get_relative_tdco() helper function
Date: Sun, 24 Oct 2021 22:43:18 +0200 [thread overview]
Message-ID: <20211024204325.3293425-9-mkl@pengutronix.de> (raw)
In-Reply-To: <20211024204325.3293425-1-mkl@pengutronix.de>
From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
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.
Link: https://lore.kernel.org/all/20210918095637.20108-7-mailhol.vincent@wanadoo.fr
CC: Stefan Mätje <Stefan.Maetje@esd.eu>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
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 b4aa0f048cab..45f19d9db5ca 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -102,6 +102,35 @@ 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)
--
2.33.0
next prev parent reply other threads:[~2021-10-24 20:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-24 20:43 pull-request: can-next 2021-10-24 Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 01/15] can: bcm: Use hrtimer_forward_now() Marc Kleine-Budde
2021-10-25 12:10 ` patchwork-bot+netdevbpf
2021-10-24 20:43 ` [PATCH net-next 02/15] can: bittiming: can_fixup_bittiming(): change type of tseg1 and alltseg to unsigned int Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 03/15] can: bittiming: allow TDC{V,O} to be zero and add can_tdc_const::tdc{v,o,f}_min Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 04/15] can: bittiming: change unit of TDC parameters to clock periods Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 05/15] can: bittiming: change can_calc_tdco()'s prototype to not directly modify priv Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 06/15] can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC) Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 07/15] can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device Marc Kleine-Budde
2021-10-24 20:43 ` Marc Kleine-Budde [this message]
2021-10-24 20:43 ` [PATCH net-next 09/15] can: at91/janz-ican3: replace snprintf() in show functions with sysfs_emit() Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 10/15] can: rcar: drop unneeded ARM dependency Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 11/15] can: mscan: mpc5xxx_can: Make use of the helper function dev_err_probe() Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 12/15] can: gs_usb: use %u to print unsigned values Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 13/15] can: peak_usb: CANFD: store 64-bits hw timestamps Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 14/15] can: xilinx_can: remove repeated word from the kernel-doc Marc Kleine-Budde
2021-10-24 20:43 ` [PATCH net-next 15/15] can: xilinx_can: xcan_remove(): remove redundant netif_napi_del() Marc Kleine-Budde
2021-10-25 12:10 ` pull-request: can-next 2021-10-24 patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211024204325.3293425-9-mkl@pengutronix.de \
--to=mkl@pengutronix.de \
--cc=Stefan.Maetje@esd.eu \
--cc=davem@davemloft.net \
--cc=kernel@pengutronix.de \
--cc=kuba@kernel.org \
--cc=linux-can@vger.kernel.org \
--cc=mailhol.vincent@wanadoo.fr \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).