[PATCH can-next v2 12/15] can: kvaser_usb: leaf: Add hardware timestamp support to usbcan devices

[Jimmy Assarsson <extja@kvaser.com>]

Add hardware timestamp support for all usbcan based devices (M16C).
The usbcan firmware is slightly different compared to the other Kvaser USB
interfaces:
  - The timestamp is provided by a 32-bit counter, with 10us resolution.
    Hence, the hardware timestamp will wrap after less than 12 hours.
  - Each Rx CAN or Tx ACK command only contains the 16-bits LSB of the
    timestamp counter.
  - The 16-bits MSB are sent in an asynchronous event (command), if any
    change occurred in the MSB since the last event.

Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
---
Changes in v2:
  - Add new helper function kvaser_usb_usbcan_timestamp_to_ktime()

 drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c |  3 ++-
 drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
index b5d762d38d5d..576ddf932f47 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -100,7 +100,8 @@ static const struct kvaser_usb_driver_info kvaser_usb_driver_info_hydra = {
 
 static const struct kvaser_usb_driver_info kvaser_usb_driver_info_usbcan = {
 	.quirks = KVASER_USB_QUIRK_HAS_TXRX_ERRORS |
-		  KVASER_USB_QUIRK_HAS_SILENT_MODE,
+		  KVASER_USB_QUIRK_HAS_SILENT_MODE |
+		  KVASER_USB_QUIRK_HAS_HARDWARE_TIMESTAMP,
 	.family = KVASER_USBCAN,
 	.ops = &kvaser_usb_leaf_dev_ops,
 };
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
index 465707174f2e..6b9122ab1464 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -121,6 +121,7 @@
 
 /* USBCanII timestamp */
 #define KVASER_USB_USBCAN_CLK_OVERFLOW_MASK GENMASK(31, 16)
+#define KVASER_USB_USBCAN_TIMESTAMP_FACTOR 10
 
 struct kvaser_cmd_simple {
 	u8 tid;
@@ -536,6 +537,15 @@ static const struct kvaser_usb_dev_cfg kvaser_usb_leaf_imx_dev_cfg_32mhz = {
 	.bittiming_const = &kvaser_usb_flexc_bittiming_const,
 };
 
+static inline ktime_t kvaser_usb_usbcan_timestamp_to_ktime(const struct kvaser_usb *dev,
+							   __le16 timestamp)
+{
+	u64 ticks = le16_to_cpu(timestamp) |
+		    dev->card_data.usbcan_timestamp_msb;
+
+	return kvaser_usb_ticks_to_ktime(dev->cfg, ticks * KVASER_USB_USBCAN_TIMESTAMP_FACTOR);
+}
+
 static int kvaser_usb_leaf_verify_size(const struct kvaser_usb *dev,
 				       const struct kvaser_cmd *cmd)
 {
@@ -978,6 +988,7 @@ static void kvaser_usb_leaf_tx_acknowledge(const struct kvaser_usb *dev,
 		hwtstamp = kvaser_usb_timestamp48_to_ktime(dev->cfg, cmd->u.leaf.tx_ack.time);
 		break;
 	case KVASER_USBCAN:
+		hwtstamp = kvaser_usb_usbcan_timestamp_to_ktime(dev, cmd->u.usbcan.tx_ack.time);
 		break;
 	}
 
@@ -1398,6 +1409,7 @@ static void kvaser_usb_leaf_rx_can_msg(const struct kvaser_usb *dev,
 		break;
 	case KVASER_USBCAN:
 		rx_data = cmd->u.usbcan.rx_can.data;
+		hwtstamp = kvaser_usb_usbcan_timestamp_to_ktime(dev, cmd->u.usbcan.rx_can.time);
 		break;
 	}
 
-- 
2.45.2