can: tree-wide: advertise software timestamping capabilities

Currently, some CAN drivers support hardware timestamping, some do
not. But userland has no method to query which features are supported
(aside maybe of getting RX messages and observe whether or not
hardware timestamps stay at zero).

The canonical way for a network driver to advertised what kind of
timestamping it supports is to implement ethtool_ops::get_ts_info().

This patch only targets the CAN drivers which *do not* support
hardware timestamping.  For each of those CAN drivers, implement the
get_ts_info() using the generic ethtool_op_get_ts_info().

This way, userland can do:

| $ ethtool --show-time-stamping canX

to confirm the device timestamping capacities.

N.B. the drivers which support hardware timestamping will be migrated
in separate patches.

Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20220727101641.198847-6-mailhol.vincent@wanadoo.fr
[mkl: mscan: add missing mscan_ethtool_ops]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 29ed0d3cd171..3a2d109a3792 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -8,6 +8,7 @@
 
 #include <linux/clk.h>
 #include <linux/errno.h>
+#include <linux/ethtool.h>
 #include <linux/if_arp.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -1152,6 +1153,10 @@ static const struct net_device_ops at91_netdev_ops = {
 	.ndo_change_mtu = can_change_mtu,
 };
 
+static const struct ethtool_ops at91_ethtool_ops = {
+	.get_ts_info = ethtool_op_get_ts_info,
+};
+
 static ssize_t mb0_id_show(struct device *dev,
 			   struct device_attribute *attr, char *buf)
 {
@@ -1293,6 +1298,7 @@ static int at91_can_probe(struct platform_device *pdev)
 	}
 
 	dev->netdev_ops	= &at91_netdev_ops;
+	dev->ethtool_ops = &at91_ethtool_ops;
 	dev->irq = irq;
 	dev->flags |= IFF_ECHO;