[PATCH 5.15 1/3] Revert "can: m_can: remove support for custom bit timing"

[Matthias Schiffer <matthias.schiffer@ew.tq-group.com>]

commit ea768b2ffec6cc9c3e17c37ef75d0539b8f89ff5 upstream.

The timing limits specified by the Elkhart Lake CPU datasheets do not
match the defaults. Let's reintroduce the support for custom bit timings.

This reverts commit 0ddd83fbebbc5537f9d180d31f659db3564be708.

Link: https://lore.kernel.org/all/00c9e2596b1a548906921a574d4ef7a03c0dace0.1636967198.git.matthias.schiffer@ew.tq-group.com
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/m_can.c | 24 ++++++++++++++++++------
 drivers/net/can/m_can/m_can.h |  3 +++
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index e330b4c121bf..c2a8421e7845 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1494,20 +1494,32 @@ static int m_can_dev_setup(struct m_can_classdev *cdev)
 	case 30:
 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.0.x */
 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
-		cdev->can.bittiming_const = &m_can_bittiming_const_30X;
-		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_30X;
+		cdev->can.bittiming_const = cdev->bit_timing ?
+			cdev->bit_timing : &m_can_bittiming_const_30X;
+
+		cdev->can.data_bittiming_const = cdev->data_timing ?
+			cdev->data_timing :
+			&m_can_data_bittiming_const_30X;
 		break;
 	case 31:
 		/* CAN_CTRLMODE_FD_NON_ISO is fixed with M_CAN IP v3.1.x */
 		can_set_static_ctrlmode(dev, CAN_CTRLMODE_FD_NON_ISO);
-		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
-		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
+		cdev->can.bittiming_const = cdev->bit_timing ?
+			cdev->bit_timing : &m_can_bittiming_const_31X;
+
+		cdev->can.data_bittiming_const = cdev->data_timing ?
+			cdev->data_timing :
+			&m_can_data_bittiming_const_31X;
 		break;
 	case 32:
 	case 33:
 		/* Support both MCAN version v3.2.x and v3.3.0 */
-		cdev->can.bittiming_const = &m_can_bittiming_const_31X;
-		cdev->can.data_bittiming_const = &m_can_data_bittiming_const_31X;
+		cdev->can.bittiming_const = cdev->bit_timing ?
+			cdev->bit_timing : &m_can_bittiming_const_31X;
+
+		cdev->can.data_bittiming_const = cdev->data_timing ?
+			cdev->data_timing :
+			&m_can_data_bittiming_const_31X;
 
 		cdev->can.ctrlmode_supported |=
 			(m_can_niso_supported(cdev) ?
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index d18b515e6ccc..ad063b101411 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -85,6 +85,9 @@ struct m_can_classdev {
 	struct sk_buff *tx_skb;
 	struct phy *transceiver;
 
+	struct can_bittiming_const *bit_timing;
+	struct can_bittiming_const *data_timing;
+
 	struct m_can_ops *ops;
 
 	int version;
-- 
2.25.1