[PATCH] net: can: ifi: Configure transmitter delay

[PATCH] net: can: ifi: Configure transmitter delay

[Marek Vasut]

Configure the transmitter delay register at +0x1c to correctly handle
the CAN FD bitrate switch (BRS). This moves the SSP (secondary sample
point) to a proper offset, so that the TDC mechanism works and won't
generate error frames on the CAN link.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Wolfgang Grandegger <wg@grandegger.com>
---
 drivers/net/can/ifi_canfd/ifi_canfd.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index 2d1d22e..368bb07 100644
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -81,6 +81,10 @@
 #define IFI_CANFD_TIME_SET_TIMEA_4_12_6_6	BIT(15)
 
 #define IFI_CANFD_TDELAY			0x1c
+#define IFI_CANFD_TDELAY_DEFAULT		0xb
+#define IFI_CANFD_TDELAY_MASK			0x3fff
+#define IFI_CANFD_TDELAY_ABS			BIT(14)
+#define IFI_CANFD_TDELAY_EN			BIT(15)
 
 #define IFI_CANFD_ERROR				0x20
 #define IFI_CANFD_ERROR_TX_OFFSET		0
@@ -641,7 +645,7 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
 	struct ifi_canfd_priv *priv = netdev_priv(ndev);
 	const struct can_bittiming *bt = &priv->can.bittiming;
 	const struct can_bittiming *dbt = &priv->can.data_bittiming;
-	u16 brp, sjw, tseg1, tseg2;
+	u16 brp, sjw, tseg1, tseg2, tdc;
 
 	/* Configure bit timing */
 	brp = bt->brp - 2;
@@ -664,6 +668,11 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
 	       (brp << IFI_CANFD_TIME_PRESCALE_OFF) |
 	       (sjw << IFI_CANFD_TIME_SJW_OFF_7_9_8_8),
 	       priv->base + IFI_CANFD_FTIME);
+
+	/* Configure transmitter delay */
+	tdc = (dbt->brp * (dbt->phase_seg1 + 1)) & IFI_CANFD_TDELAY_MASK;
+	writel(IFI_CANFD_TDELAY_EN | IFI_CANFD_TDELAY_ABS | tdc,
+	       priv->base + IFI_CANFD_TDELAY);
 }
 
 static void ifi_canfd_set_filter(struct net_device *ndev, const u32 id,
-- 
2.9.3

Re: [PATCH] net: can: ifi: Configure transmitter delay

[Marc Kleine-Budde]

[-- Attachment #1.1: Type: text/plain, Size: 857 bytes --]

On 09/19/2016 09:34 PM, Marek Vasut wrote:
> Configure the transmitter delay register at +0x1c to correctly handle
> the CAN FD bitrate switch (BRS). This moves the SSP (secondary sample
> point) to a proper offset, so that the TDC mechanism works and won't
> generate error frames on the CAN link.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Marc Kleine-Budde <mkl@pengutronix.de>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Oliver Hartkopp <socketcan@hartkopp.net>
> Cc: Wolfgang Grandegger <wg@grandegger.com>

Applied to linux-can.

Thanks,
Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
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pull-request: can 2016-09-21

[Marc Kleine-Budde]

Hello David,

this is another pull request of one patch for the upcoming linux-4.8 release.

Marek Vasut fixes the CAN-FD bit rate switch in the ifi driver by configuring
the transmitter delay.

regards,
Marc

---

The following changes since commit b5036cd4ed3173ab8cdbc85e2ba74acf46bafb51:

  ipmr, ip6mr: return lastuse relative to now (2016-09-21 00:58:23 -0400)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can.git tags/linux-can-fixes-for-4.8-20160921

for you to fetch changes up to 8d58790b832e13d6006d842037732304af357c3c:

  net: can: ifi: Configure transmitter delay (2016-09-21 10:32:24 +0200)

----------------------------------------------------------------
linux-can-fixes-for-4.8-20160921

----------------------------------------------------------------
Marek Vasut (1):
      net: can: ifi: Configure transmitter delay

 drivers/net/can/ifi_canfd/ifi_canfd.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

[PATCH] net: can: ifi: Configure transmitter delay

[Marc Kleine-Budde]

From: Marek Vasut <marex@denx.de>

Configure the transmitter delay register at +0x1c to correctly handle
the CAN FD bitrate switch (BRS). This moves the SSP (secondary sample
point) to a proper offset, so that the TDC mechanism works and won't
generate error frames on the CAN link.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/ifi_canfd/ifi_canfd.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index 2d1d22eec750..368bb0710d8f 100644
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -81,6 +81,10 @@
 #define IFI_CANFD_TIME_SET_TIMEA_4_12_6_6	BIT(15)
 
 #define IFI_CANFD_TDELAY			0x1c
+#define IFI_CANFD_TDELAY_DEFAULT		0xb
+#define IFI_CANFD_TDELAY_MASK			0x3fff
+#define IFI_CANFD_TDELAY_ABS			BIT(14)
+#define IFI_CANFD_TDELAY_EN			BIT(15)
 
 #define IFI_CANFD_ERROR				0x20
 #define IFI_CANFD_ERROR_TX_OFFSET		0
@@ -641,7 +645,7 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
 	struct ifi_canfd_priv *priv = netdev_priv(ndev);
 	const struct can_bittiming *bt = &priv->can.bittiming;
 	const struct can_bittiming *dbt = &priv->can.data_bittiming;
-	u16 brp, sjw, tseg1, tseg2;
+	u16 brp, sjw, tseg1, tseg2, tdc;
 
 	/* Configure bit timing */
 	brp = bt->brp - 2;
@@ -664,6 +668,11 @@ static void ifi_canfd_set_bittiming(struct net_device *ndev)
 	       (brp << IFI_CANFD_TIME_PRESCALE_OFF) |
 	       (sjw << IFI_CANFD_TIME_SJW_OFF_7_9_8_8),
 	       priv->base + IFI_CANFD_FTIME);
+
+	/* Configure transmitter delay */
+	tdc = (dbt->brp * (dbt->phase_seg1 + 1)) & IFI_CANFD_TDELAY_MASK;
+	writel(IFI_CANFD_TDELAY_EN | IFI_CANFD_TDELAY_ABS | tdc,
+	       priv->base + IFI_CANFD_TDELAY);
 }
 
 static void ifi_canfd_set_filter(struct net_device *ndev, const u32 id,
-- 
2.9.3