command_registration: add empty usage field to chained commands

Chained command require a subcommand as first argument. The usage
field for chained commands is not really important because the
"help" command will list all the subcommands with their respective
usage.

Add a empty usage field on all chained command.
The command "jlink config" can be either followed by a subcommand
or used alone, so use a dedicated usage string.

Change-Id: I43c3f8a766f96a9bdab4e709e3c90713be41fcef
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5017
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

src/flash/nand/mxc.c

@@ -193,7 +193,8 @@ static const struct command_registration mxc_nand_command_handler[] = {
 		.name = "mxc",
 		.mode = COMMAND_ANY,
 		.help = "MXC NAND flash controller commands",
-		.chain = mxc_sub_command_handlers
+		.chain = mxc_sub_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/flash/nor/faux.c

@@ -109,6 +109,7 @@ static const struct command_registration faux_command_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "faux flash command group",
 		.chain = hello_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/flash/nor/max32xxx.c

@@ -977,6 +977,7 @@ static const struct command_registration max32xxx_command_handlers[] = {
 		.mode = COMMAND_EXEC,
 		.help = "max32xxx flash command group",
 		.chain = max32xxx_exec_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/flash/nor/tcl.c

@@ -1260,6 +1260,7 @@ static const struct command_registration flash_command_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "NOR flash command group",
 		.chain = flash_config_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/hello.c

@@ -105,8 +105,8 @@ const struct command_registration hello_command_handlers[] = {
 		.name = "foo",
 		.mode = COMMAND_ANY,
 		.help = "example command handler skeleton",
-
 		.chain = foo_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/helper/command.c

@@ -1294,6 +1294,7 @@ static const struct command_registration command_builtin_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "core command group (introspection)",
 		.chain = command_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/jtag/drivers/dummy.c

@@ -136,8 +136,8 @@ static const struct command_registration dummy_command_handlers[] = {
 		.name = "dummy",
 		.mode = COMMAND_ANY,
 		.help = "dummy interface driver commands",
-
 		.chain = hello_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE,
 };

src/jtag/drivers/jlink.c

@@ -1849,12 +1849,14 @@ static const struct command_registration jlink_subcommand_handlers[] = {
 		.help = "access the device configuration. If no argument is given "
 			"this will show the device configuration",
 		.chain = jlink_config_subcommand_handlers,
+		.usage = "[<cmd>]",
 	},
 	{
 		.name = "emucom",
 		.mode = COMMAND_EXEC,
 		.help = "access EMUCOM channel",
-		.chain = jlink_emucom_subcommand_handlers
+		.chain = jlink_emucom_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };
@@ -1865,6 +1867,7 @@ static const struct command_registration jlink_command_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "perform jlink management",
 		.chain = jlink_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/arm_cti.c

@@ -576,6 +576,7 @@ static const struct command_registration cti_command_handlers[] = {
 		.mode = COMMAND_CONFIG,
 		.help = "CTI commands",
 		.chain = cti_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/arm_dap.c

@@ -373,6 +373,7 @@ static const struct command_registration dap_commands[] = {
 		.mode = COMMAND_CONFIG,
 		.help = "DAP commands",
 		.chain = dap_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/etb.c

@@ -441,6 +441,7 @@ static const struct command_registration etb_command_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "Embedded Trace Buffer command group",
 		.chain = etb_config_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/etm_dummy.c

@@ -66,6 +66,7 @@ static const struct command_registration etm_dummy_command_handlers[] = {
 		.mode = COMMAND_ANY,
 		.help = "Dummy ETM capture driver command group",
 		.chain = etm_dummy_config_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/target.c

@@ -6096,8 +6096,8 @@ static const struct command_registration target_command_handlers[] = {
 		.name = "target",
 		.mode = COMMAND_CONFIG,
 		.help = "configure target",
-
 		.chain = target_subcommand_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };

src/target/testee.c

@@ -30,8 +30,8 @@ static const struct command_registration testee_command_handlers[] = {
 		.name = "testee",
 		.mode = COMMAND_ANY,
 		.help = "testee target commands",
-
 		.chain = hello_command_handlers,
+		.usage = "",
 	},
 	COMMAND_REGISTRATION_DONE
 };