devlink: Add usage help for eswitch subcommand

Add missing usage help for devlink dev eswitch subcommand.

Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
diff --git a/devlink/devlink.c b/devlink/devlink.c
index ccca0fb..673234f 100644
--- a/devlink/devlink.c
+++ b/devlink/devlink.c
@@ -963,6 +963,8 @@
 static void cmd_dev_help(void)
 {
 	pr_err("Usage: devlink dev show [ DEV ]\n");
+	pr_err("       devlink dev eswitch set DEV [ mode { legacy | switchdev } ]\n");
+	pr_err("       devlink dev eswitch show DEV\n");
 }
 
 static bool cmp_arr_last_handle(struct dl *dl, const char *bus_name,
@@ -1259,7 +1261,10 @@
 
 static int cmd_dev_eswitch(struct dl *dl)
 {
-	if (dl_argv_match(dl, "set")) {
+	if (dl_argv_match(dl, "help") || dl_no_arg(dl)) {
+		cmd_dev_help();
+		return 0;
+	} else if (dl_argv_match(dl, "set")) {
 		dl_arg_inc(dl);
 		return cmd_dev_eswitch_set(dl);
 	} else if (dl_argv_match(dl, "show")) {
diff --git a/man/man8/devlink-dev.8 b/man/man8/devlink-dev.8
index 9ce3193..931e334 100644
--- a/man/man8/devlink-dev.8
+++ b/man/man8/devlink-dev.8
@@ -54,7 +54,7 @@
 
 .TP
 .BR mode " { " legacy " | " switchdev " } "
-set eswitch mode
+Set eswitch mode
 
 .I legacy
 - Legacy SRIOV