[PATCH 2/2] can: flexcan: add ISO CAN FD feature support

[Joakim Zhang <qiangqing.zhang@xxxxxxx>]

ISO CAN FD is introduced to increase the failture detection capability
than non-ISO CAN FD. The non-ISO CAN FD is still supported by FlexCAN so
that it can be used mainly during an intermediate phase, for evaluation
and development purposes.

Therefore, it is strongly recommended to configure FlexCAN to the ISO
CAN FD protocol by setting the ISOCANFDEN field in the CTRL2 register.

Test Command:
ISO FD MODE:
ip link set can0 type can bitrate 1000000 dbitrate 4000000 fd on
fd-non-iso off

non-ISO FD MODE:
ip link set can0 type can bitrate 1000000 dbitrate 4000000 fd on
fd-non-iso on

NOTE: if you only set "fd on", driver will use ISO FD MODE by default.

Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
---
 drivers/net/can/flexcan.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 4ba35f9eb515..25e077a68db9 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -91,6 +91,7 @@
 #define FLEXCAN_CTRL2_MRP		BIT(18)
 #define FLEXCAN_CTRL2_RRS		BIT(17)
 #define FLEXCAN_CTRL2_EACEN		BIT(16)
+#define FLEXCAN_CTRL2_ISOCANFDEN	BIT(12)
 
 /* FLEXCAN memory error control register (MECR) bits */
 #define FLEXCAN_MECR_ECRWRDIS		BIT(31)
@@ -1227,6 +1228,12 @@ static int flexcan_chip_start(struct net_device *dev)
 		priv->write(reg_fdctrl, &regs->fdctrl);
 		reg_mcr = priv->read(&regs->mcr);
 		priv->write(reg_mcr | FLEXCAN_MCR_FDEN, &regs->mcr);
+
+		reg_ctrl2 = flexcan_read(&regs->ctrl2);
+		if (!(priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO))
+			flexcan_write(reg_ctrl2 | FLEXCAN_CTRL2_ISOCANFDEN, &regs->ctrl2);
+		else
+			flexcan_write(reg_ctrl2 & ~FLEXCAN_CTRL2_ISOCANFDEN, &regs->ctrl2);
 	}
 
 	if ((priv->can.ctrlmode_supported & CAN_CTRLMODE_FD) &&
@@ -1729,7 +1736,7 @@ static int flexcan_probe(struct platform_device *pdev)
 	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD) {
 		if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
 			priv->offload.is_canfd = true;
-			priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
+			priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD | CAN_CTRLMODE_FD_NON_ISO;
 			priv->can.bittiming_const = &flexcan_fd_bittiming_const;
 			priv->can.data_bittiming_const = &flexcan_fd_data_bittiming_const;
 		} else {
-- 
2.17.1