From df06fd678260bca919ea894281ec54ce10e45ce6 Mon Sep 17 00:00:00 2001 From: Torin Cooper-Bennun Date: Mon, 8 Mar 2021 10:24:27 +0000 Subject: [PATCH] can: m_can: m_can_chip_config(): enable and configure internal timestamps This is a prerequisite for transitioning the m_can driver to rx-offload, which works best with TX and RX timestamps. The timestamps provided by M_CAN are 16-bit, timed according to the nominal bit timing, and may be prescaled by a multiplier up to 16. We choose the highest prescalar so that the timestamp wraps every 2^20 bit times, or 209 ms at a bus speed of 5 Mbit/s. Timestamps will have a precision of 16 bit times. Link: https://lore.kernel.org/r/20210308102427.63916-3-torin@maxiluxsystems.com Signed-off-by: Torin Cooper-Bennun Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 9f7cfe91f7ff..7df81e38b043 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1135,6 +1135,7 @@ static int m_can_set_bittiming(struct net_device *dev) * - >= v3.1.x: TX FIFO is used * - configure mode * - setup bittiming + * - configure timestamp generation */ static void m_can_chip_config(struct net_device *dev) { @@ -1246,6 +1247,10 @@ static void m_can_chip_config(struct net_device *dev) /* set bittiming params */ m_can_set_bittiming(dev); + /* enable internal timestamp generation, with a prescalar of 16. The + * prescalar is applied to the nominal bit timing */ + m_can_write(cdev, M_CAN_TSCC, FIELD_PREP(TSCC_TCP_MASK, 0xf)); + m_can_config_endisable(cdev, false); if (cdev->ops->init) -- 2.11.0