doc: subsystems: shell: Add documentation.

1. Remove old shell documentation.
2. Create documentation for new shell module.
3. Fix shell.h comments to be able to generate
   API documentation.

Signed-off-by: Jakub Rzeszutko <jakub.rzeszutko@nordicsemi.no>

doc/api/api.rst

@@ -27,3 +27,4 @@ The Zephyr APIs are used the same way on all SoCs and boards.
    display_api
    misc_api
    logger_api
+   shell_api

doc/api/shell_api.rst

@@ -0,0 +1,16 @@
+
+.. _shell_api:
+
+Shell system API
+#################
+
+.. contents::
+   :depth: 2
+   :local:
+   :backlinks: top
+
+Shell API
+**********
+
+.. doxygengroup:: shell_api
+   :project: Zephyr

doc/subsystems/shell.rst

@@ -1,182 +0,0 @@
-.. _shell:
-
-Shell
-######
-
-Overview
-********
-
-The Shell enables multiple subsystem to use and expose their shell interface
-simultaneously.
-
-Each subsystem can support shell functionality dynamically by its Kconfig file,
-which enables or disables the shell usage for the subsystem.
-
-Using shell commands
-********************
-
-Use one of the following formats:
-
-Help commands
-=============
-
-``help``
- Prints the list of available modules.
-
-``help MODULE_NAME``
- Prints the names of the available commands for the module.
-
-``help MODULE_NAME COMMAND``
- Prints help for the module's command (the help describes the available
- module commands and required parameters).
-
-
-Specific module's commands
-==========================
-
-A shell interface exposing subsystem features is a shell module, multiple
-modules can be available at the same time.
-
-``MODULE_NAME COMMAND``
- One of the available modules is "KERNEL", for `Kernel module commands`_.
- Information about registering a new module and its commands can be
- found in :c:macro:`SHELL_REGISTER` documentation.
-
-
-Select module commands
-======================
-
-``select MODULE_NAME``
- Use this command when using the shell only for one module. After entering this
- command, you will not need to enter the module name in further commands. If
- the selected module has set a default shell prompt during its initialization,
- the prompt will be changed to that one. Otherwise, the prompt will be
- changed to the selected module's name to reflect the current module in use.
-
-``select``
- Clears selected module. Restores prompt as well.
-
-
-Kernel module commands
-======================
-
-When enabled through option :option:`CONFIG_KERNEL_SHELL`, the Kernel
-shell module commands display useful kernel-specific information.
-
-You can issue these Kernel module shell commands by specifying
-the module and command::
-
-   shell> kernel version
-
-or by first selecting the kernel module, and then issuing the specific
-command::
-
-   shell> select kernel
-   kernel> version
-
-Here are the Kernel module shell commands:
-
-``version``
- Displays the kernel version number
-
-``uptime``
- Displays the system uptime in milliseconds
-
-``cycles``
- Displays the current time (in cycles), as measured by the system's hardware clock
-
-``threads``
- Displays information about the running threads (if
- :option:`CONFIG_OBJECT_TRACING` and :option:`CONFIG_THREAD_MONITOR` are
- enabled).
-
-``stacks``
- Displays size and use information about the main, idle, interrupt and system
- workqueue call stacks (if :option:`CONFIG_INIT_STACKS` is enabled)
-
-Other commands
-==============
-
-``noprompt``
- This command will disable the shell prompt. The shell will still be fully
- functional, but the prompt will not be printed each time the shell expects a
- new command.
-
-Shell configuration
-*******************
-There are two levels of configuration: Infrastructure level and Module level.
-
-Infrastructure level
-====================
-
-The option :option:`CONFIG_CONSOLE_SHELL` enables the shell subsystem and enable the
-default features of the shell subsystem.
-
-Module/Subsystem level
-======================
-Each subsystem using the shell service should add a unique flag in its Kconfig file.
-
-Example:
-
-CONFIG_NET_SHELL=y
-
-In the subsystem's code, the shell usage depends on this config parameter.
-This subsystem specific flag should also depend on :option:`CONFIG_CONSOLE_SHELL` flag.
-
-Configuration steps to add shell functionality to a module
-==========================================================
-
- #. Check that :option:`CONFIG_CONSOLE_SHELL` is set to yes.
- #. Add the subsystem unique flag to its Kconfig file.
-
-Writing a shell module
-**********************
-
-In order to support shell in your subsystem, the application must do the following:
-
-#. Module configuration flag: Declare a new flag in your subsystem Kconfig file.
-   It should depend on :option:`CONFIG_CONSOLE_SHELL` flag.
-
-#. Module registration to shell: Add your shell identifier and register its
-   callback functions in the shell database using :c:macro:`SHELL_REGISTER`.
-
-Optionally, you can use one of the following API functions to override default
-behavior and settings:
-
-* :c:func:`shell_register_default_module`
-
-* :c:func:`shell_register_prompt_handler`
-
-In case of a sample applications as well as the test environment, you can choose to
-set a default module in code level. In this case, the function
-:c:func:`shell_register_default_module` should be called after calling SHELL_REGISTER in
-application level.  If the function
-:c:func:`shell_register_prompt_handler` was called as
-well, the prompt will be changed to that one.  Otherwise, the prompt will be
-changed to the selected module's name, in order to reflect the current module in
-use.
-
-
-.. note::
-
-   Even if a default module was set in code level, it can be overwritten by
-   "select" shell command.
-
-You can use  :c:func:`shell_register_default_module` in the following cases:
-
-* Use this command in case of using the shell only for one module.
-  After entering this command, no need to enter module name in further
-  commands.
-
-* Use this function for shell backward compatibility.
-
-More details on those optional functions can be found in
-:ref:`shell_api_functions`.
-
-
-.. _shell_api_functions:
-
-Shell API Functions
-*******************
-.. doxygengroup:: _shell_api_functions
-   :project: Zephyr

doc/subsystems/shell/shell.rst

@@ -0,0 +1,510 @@
+.. _shell:
+
+Shell
+######
+
+Overview
+********
+
+This module allows you to create and handle a shell with a user-defined command
+set. You can use it in examples where more than simple button or LED user
+interaction is required. This module is a Unix-like shell with these features:
+
+* Support for multiple instances.
+* Advanced cooperation with the :ref:`logger`.
+* Support for static and dynamic commands.
+* Smart command completion with the :kbd:`Tab` key.
+* Built-in commands: :command:`clear`, :command:`shell`, :command:`colors`,
+  :command:`echo`, :command:`history` and :command:`resize`.
+* Viewing recently executed commands using keys: :kbd:`↑` :kbd:`↓`.
+* Text edition using keys: :kbd:`←`, :kbd:`→`, :kbd:`Backspace`,
+  :kbd:`Delete`, :kbd:`End`, :kbd:`Home`, :kbd:`Insert`.
+* Support for ANSI escape codes: ``VT100`` and ``ESC[n~`` for cursor control
+  and color printing.
+* Support for multiline commands.
+* Built-in handler to display help for the commands.
+* Support for wildcards: ``*`` and ``?``.
+* Support for meta keys.
+* Kconfig configuration to optimize memory usage.
+
+The module can be connected to any transport for command input and output.
+At this point, the following transport layers are implemented:
+
+* UART
+
+See the :ref:`shell_api` documentation for more information.
+
+Commands
+********
+
+Shell commands are organized in a tree structure and grouped into the following
+types:
+
+* Root command (level 0): Gathered and alphabetically sorted in a dedicated
+  memory section.
+* Static subcommand (level > 0): Number and syntax must be known during compile
+  time. Created in the software module.
+* Dynamic subcommand (level > 0): Number and syntax does not need to be known
+  during compile time. Created in the software module.
+
+Creating commands
+=================
+
+Use the following macros for adding shell commands:
+
+* :c:macro:`SHELL_CMD_REGISTER` - Create root command. All root commands must
+  have different name.
+* :c:macro:`SHELL_CMD` - Initialize a command.
+* :c:macro:`SHELL_CREATE_STATIC_SUBCMD_SET` - Create a static subcommands
+  array. Static subcommands must be added in alphabetical order to ensure
+  correct smart completion.
+* :c:macro:`SHELL_SUBCMD_SET_END` - shall be placed as last in
+  :c:macro:`SHELL_CREATE_STATIC_SUBCMD_SET` macro.
+* :c:macro:`SHELL_CREATE_DYNAMIC_CMD` - Create a dynamic subcommands array.
+  Dynamic subcommands must be returned in alphabetical order to ensure correct
+  smart completion.
+
+Commands can be created in any file in the system that includes
+:file:`include/shell/shell.h`. All created commands are available for all
+shell instances.
+
+Static commands
+---------------
+
+Example code demonstrating how to create a root command with static
+subcommands.
+
+.. image:: images/static_cmd.PNG
+      :align: center
+      :alt: Command tree with static commands.
+
+.. code-block:: c
+
+	/* Creating subcommands (level 1 command) array for command "demo".
+	 * Subcommands must be added in alphabetical order to ensure correct
+	 * command autocompletion.
+	 */
+	SHELL_CREATE_STATIC_SUBCMD_SET(sub_demo)
+	{
+		/* Alphabetically sorted. */
+		SHELL_CMD(params, NULL, "Print params command.",
+						       cmd_demo_params),
+		SHELL_CMD(ping,   NULL, "Ping command.", cmd_demo_ping),
+		SHELL_SUBCMD_SET_END /* Array terminated. */
+	};
+	/* Creating root (level 0) command "demo" */
+	SHELL_CMD_REGISTER(demo, &sub_demo, "Demo commands", NULL);
+
+Example implementation can be found under following location:
+:file:`samples/subsys/shell/shell_module/src/main.c`.
+
+Dynamic commands
+----------------
+
+Example code demonstrating how to create a root command with static and dynamic
+subcommands. At the beginning dynamic command list is empty. New commands
+can be added by typing:
+
+.. code-block:: none
+
+	dynamic add <new_dynamic_command>
+
+Newly added commands can be prompted or autocompleted with the :kbd:`Tab` key.
+
+.. image:: images/dynamic_cmd.PNG
+      :align: center
+      :alt: Command tree with static and dynamic commands.
+
+.. code-block:: c
+
+	/* Buffer for 10 dynamic commands */
+	static char dynamic_cmd_buffer[10][50];
+
+	/* commands counter */
+	static u8_t dynamic_cmd_cnt;
+
+	/* Function returning command dynamically created
+	 * in  dynamic_cmd_buffer.
+	 */
+	static void dynamic_cmd_get(size_t idx,
+				    struct shell_static_entry *entry)
+	{
+		if (idx < dynamic_cmd_cnt) {
+			/* m_dynamic_cmd_buffer must be sorted alphabetically
+			 * to ensure correct Shell autocompletion
+			 */
+			entry->syntax = dynamic_cmd_buffer[idx];
+			entry->handler  = NULL;
+			entry->subcmd = NULL;
+			entry->help = "Show dynamic command name.";
+		} else {
+			/* if there are no more dynamic commands available
+			 * syntax must be set to NULL.
+			 */
+			entry->syntax = NULL;
+		}
+	}
+
+	SHELL_CREATE_DYNAMIC_CMD(m_sub_dynamic_set, dynamic_cmd_get);
+	SHELL_CREATE_STATIC_SUBCMD_SET(m_sub_dynamic)
+	{
+		SHELL_CMD(add, NULL,"Add new command to dynamic_cmd_buffer and"
+			  " sort them alphabetically.",
+			  cmd_dynamic_add),
+		SHELL_CMD(execute, &m_sub_dynamic_set,
+			  "Execute a command.", cmd_dynamic_execute),
+		SHELL_CMD(remove, &m_sub_dynamic_set,
+			  "Remove a command from dynamic_cmd_buffer.",
+			  cmd_dynamic_remove),
+		SHELL_CMD(show, NULL,
+			  "Show all commands in dynamic_cmd_buffer.",
+			  cmd_dynamic_show),
+		SHELL_SUBCMD_SET_END
+	};
+	SHELL_CMD_REGISTER(dynamic, &m_sub_dynamic,
+		   "Demonstrate dynamic command usage.", cmd_dynamic);
+
+Example implementation can be found under following location:
+:file:`samples/subsys/shell/shell_module/src/dynamic_cmd.c`.
+
+Commands execution
+==================
+
+Each command or subcommand may have a handler. The shell executes the handler
+that is found deepest in the command tree and further subcommands (without a
+handler) are passed as arguments. Characters within parentheses are treated
+as one argument. If shell wont find a handler it will display an error message.
+
+Command handler
+----------------
+
+Simple command handler implementation:
+
+.. code-block:: c
+
+	static void cmd_handler(const struct shell *shell, size_t argc,
+				char **argv)
+	{
+		ARG_UNUSED(argc);
+		ARG_UNUSED(argv);
+
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "Print simple text.\r\n");
+
+		shell_fprintf(shell, SHELL_WARNING,
+			      "Print warning text.\r\n");
+
+		shell_fprintf(shell, SHELL_ERROR,
+			      "Print error text.\r\n");
+	}
+
+.. warning::
+	Do not use function :cpp:func:`shell_fprintf` outside of the command
+	handler because this might lead to incorrect text display on the
+	screen. If any text should be displayed outside of the command context,
+	then use the :ref:`logger`.
+
+Command help
+------------
+
+Every user-defined command, subcommand, or option can have its own help
+description. The help for commands and subcommands can be created with
+respective macros: :c:macro:`SHELL_CMD_REGISTER` and :c:macro:`SHELL_CMD`.
+In addition, you can define options for commands or subcommands using the
+macro :c:macro:`SHELL_OPT`. By default, each and every command or subcommand
+has these two options implemented: ``-h`` and ``--help``.
+
+In order to add help functionality to a command or subcommand, you must
+implement the help handler by either calling :cpp:func:`shell_cmd_precheck`
+or pair of functions :cpp:func:`shell_help_requested` and
+:cpp:func:`shell_help_print`. The former is more convenient as it also
+checks for valid arguments count.
+
+.. code-block:: c
+
+	static void cmd_dummy_1(const struct shell *shell, size_t argc,
+				char **argv)
+	{
+		ARG_UNUSED(argv);
+
+		/* Function shell_cmd_precheck will do one of below actions:
+		 * 1. print help if command called with -h or --help
+		 * 2. print error message if argc > 2
+		 *
+		 * Each of these actions can be deactivated in Kconfig.
+		 */
+		if (!shell_cmd_precheck(shell, (argc <= 2), NULL, 0) {
+			return;
+		}
+
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "Command called with no -h or --help option."
+			      "\r\n");
+	}
+
+	static void cmd_dummy_2(const struct shell *shell, size_t argc,
+				char **argv)
+	{
+		ARG_UNUSED(argc);
+		ARG_UNUSED(argv);
+
+		if (hell_help_requested(shell) {
+			shell_help_print(shell, NULL, 0);
+			return;
+		}
+
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "Command called with no -h or --help option."
+			      "\r\n");
+	}
+
+Command options
+---------------
+
+When possible, use subcommands instead of options.  Options apply mainly in the
+case when an argument with ``-`` or ``--`` is requested. The main benefit of
+using subcommands is that they can be prompted or completed with the :kbd:`Tab`
+key. In addition, subcommands can have their own handler, which limits the
+usage of ``if - else if`` statements combination with the ``strcmp`` function
+in command handler.
+
+
+.. code-block:: c
+
+	static void cmd_with_options(const struct shell *shell, size_t argc,
+				     char **argv)
+	{
+		/* Dummy options showing options usage */
+		static const struct shell_getopt_option opt[] = {
+			SHELL_OPT(
+				"--test",
+				"-t",
+				"test option help string"
+			),
+			SHELL_OPT(
+				"--dummy",
+				"-d",
+				"dummy option help string"
+			)
+		};
+
+		/* If command will be called with -h or --help option
+		 * all declared options will be listed in the help message
+		 */
+		if (!shell_cmd_precheck(shell, (argc <= 2), opt,
+					  sizeof(opt)/sizeof(opt[1]))) {
+			return;
+		}
+
+		/* checking if command was called with test option */
+		if (!strcmp(argv[1], "-t") || !strcmp(argv[1], "--test")) {
+		    shell_fprintf(shell, SHELL_NORMAL, "Command called with -t"
+				  " or --test option.\r\n");
+		    return;
+		}
+
+		/* checking if command was called with dummy option */
+		if (!strcmp(argv[1], "-d") || !strcmp(argv[1], "--dummy")) {
+		    shell_fprintf(shell, SHELL_NORMAL, "Command called with -d"
+				  " or --dummy option.\r\n");
+		    return;
+		}
+
+		shell_fprintf(shell, SHELL_WARNING,
+			      "Command called with no valid option.\r\n");
+	}
+
+Parent commands
+---------------
+
+In the subcommand handler, you can access both the parameters passed to
+commands or the parent commands, depending on how you index ``argv``.
+
+* When indexing ``argv`` with positive numbers, you can access the parameters.
+* When indexing ``argv`` with negative numbers, you can access the parent
+  commands.
+* The subcommand to which the handler belongs has the ``argv`` value of 0.
+
+.. code-block:: c
+
+	static void cmd_handler(const struct shell *shell, size_t argc,
+					char **argv)
+	{
+		ARG_UNUSED(argc);
+
+		/* If it is a subcommand handler parent command syntax
+		 * can be found using argv[-1].
+		 */
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "This command has a parent command: %s\r\n",
+			      argv[-1]);
+
+		/* Print this command syntax */
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "This command syntax is: %s\r\n",
+			      argv[0]);
+
+		/* Print first argument */
+		shell_fprintf(shell, SHELL_NORMAL,
+			      "This command has an argument: %s\r\n",
+			      argv[1]);
+	}
+
+Built-in commands
+=================
+
+* :command:`clear` - Clears the screen.
+* :command:`history` - Shows the recently entered commands.
+* :command:`resize` - Must be executed when terminal width is different than 80
+  characters or after each change of terminal width. It ensures proper
+  multiline text display and :kbd:`←`, :kbd:`→`, :kbd:`End`, :kbd:`Home` keys
+  handling. Currently this command works only with UART flow control switched
+  on. It can be also called with a subcommand:
+
+	* :command:`default` - Shell will send terminal width = 80 to the
+	  terminal and assume successful delivery.
+
+* :command:`shell` - Root command with useful shell-related subcommands like:
+
+	* :command:`echo` - Toggles shell echo.
+        * :command:`colors` - Toggles colored syntax. This might be helpful in
+          case of Bluetooth shell to limit the amount of transferred bytes.
+	* :command:`stats` - Shows shell statistics.
+
+Wildcards
+*********
+
+The shell module can handle wildcards. Wildcards are interpreted correctly
+when expanded command and its subcommands do not have a handler. For example,
+if you want to set logging level to ``err`` for the ``app`` and ``app_test``
+modules you can execute the following command:
+
+.. code-block:: none
+
+	log enable err a*
+
+.. image:: images/wildcard.png
+      :align: center
+      :alt: Wildcard usage example
+
+Meta keys
+*********
+
+The shell module supports the following meta keys:
+
+.. list-table:: Implemented meta keys
+   :widths: 10 40
+   :header-rows: 1
+
+   * - Meta keys
+     - Action
+   * - ctrl + a
+     - Moves the cursor to the beginning of the line.
+   * - ctrl + c
+     - Preserves the last command on the screen and starts a new command in
+       a new line.
+   * - ctrl + e
+     - Moves the cursor to the end of the line.
+   * - ctrl + l
+     - Clears the screen and leaves the currently typed command at the top of
+       the screen.
+   * - ctrl + u
+     - Clears the currently typed command.
+   * - ctrl + w
+     - Removes the word or part of the word to the left of the cursor. Words
+       separated by period instead of space are treated as one word.
+
+Usage
+*****
+
+Use the :c:macro:`SHELL_DEFINE` macro to create an instance of the shell.
+Pass the expected newline character to this macro: either ``\r`` or ``\n``,
+otherwise the shell will not respond correctly to the :kbd:`Enter` key.
+
+The following code shows a simple use case of this library:
+
+.. code-block:: c
+
+	/* Defining shell backend */
+	SHELL_UART_DEFINE(shell_transport_uart);
+
+	/* Creating shell instance */
+	SHELL_DEFINE(uart_shell, "uart:~$ ", &shell_transport_uart, '\r', 10);
+
+	void main(void)
+	{
+		(void)shell_init(&uart_shell, NULL, true, true, LOG_LEVEL_INF);
+	}
+
+	static void cmd_demo_ping(const struct shell *shell, size_t argc,
+				  char **argv)
+	{
+		ARG_UNUSED(argc);
+		ARG_UNUSED(argv);
+
+		shell_fprintf(shell, SHELL_NORMAL, "pong\r\n");
+	}
+
+	static void cmd_demo_params(const struct shell *shell, size_t argc,
+				    char **argv)
+	{
+		int cnt;
+
+		shell_fprintf(shell, SHELL_NORMAL, "argc = %d\r\n", argc);
+		for (cnt = 0; cnt < argc; cnt++) {
+			shell_fprintf(shell, SHELL_NORMAL,
+					"  argv[%d] = %s\r\n", cnt, argv[cnt]);
+		}
+	}
+
+	/* Creating subcommands (level 1 command) array for command "demo".
+	 * Subcommands must be added in alphabetical order
+	 */
+	SHELL_CREATE_STATIC_SUBCMD_SET(sub_demo)
+	{
+		/* Alphabetically sorted. */
+		SHELL_CMD(params, NULL, "Print params command.",
+						       cmd_demo_params),
+		SHELL_CMD(ping,   NULL, "Ping command.", cmd_demo_ping),
+		SHELL_SUBCMD_SET_END /* Array terminated. */
+	};
+	/* Creating root (level 0) command "demo" without a handler */
+	SHELL_CMD_REGISTER(demo, &sub_demo, "Demo commands", NULL);
+
+	/* Creating root (level 0) command "version" */
+	SHELL_CMD_REGISTER(version, NULL, "Show kernel version", cmd_version);
+
+
+Users may use the :kbd:`Tab` key to complete a command/subcommand or to see the
+available subcommands for the currently entered command level.
+For example, when the cursor is positioned at the beginning of the command
+line and the :kbd:`Tab` key is pressed, the user will see all root (level 0)
+commands:
+
+.. code-block:: none
+
+	  clear  demo  shell  history  log  resize  version
+
+
+.. note::
+	To view the subcommands that are available for a specific command, you
+	must first type a :kbd:`space` after this command and then hit
+	:kbd:`Tab`.
+
+These commands are registered by various modules, for example:
+
+* :command:`clear`, :command:`shell`, :command:`history`, and :command:`resize`
+  are built-in commands which have been registered by
+  :file:`subsys/shell/shell.c`
+* :command:`demo` and :command:`version` have been registered in example code
+  above by main.c
+* :command:`log` has been registered by :file:`subsys/logging/log_cmds.c`
+
+Then, if a user types a :command:`demo` command and presses the :kbd:`Tab` key,
+the shell will only print the subcommands registered for this command:
+
+.. code-block:: none
+
+	  params  ping
+
+

doc/subsystems/subsystems.rst

@@ -18,7 +18,7 @@ to applications.
    networking/networking.rst
    power_management.rst
    sensor
-   shell
+   shell/shell
    test/index
    usb/usb.rst
    settings/settings.rst

include/shell/shell.h

@@ -32,18 +32,16 @@ extern "C" {
 
 #define SHELL_CMD_ROOT_LVL		(0u)
 
-/*
+/**
- * @defgroup shell Shell
+ * @brief Shell API
- * @ingroup subsys
+ * @defgroup shell_api Shell API
- *
+ * @ingroup shell
- * @brief Module for providing shell.
- *
  * @{
  */
 
 struct shell_static_entry;
 
-/*
+/**
  * @brief Shell dynamic command descriptor.
  *
  * @details Function shall fill the received shell_static_entry structure
@@ -57,12 +55,12 @@ struct shell_static_entry;
 typedef void (*shell_dynamic_get)(size_t idx,
 				  struct shell_static_entry *entry);
 
-/*
+/**
  * @brief Shell command descriptor.
  */
 struct shell_cmd_entry {
 	bool is_dynamic;
-	union {
+	union union_cmd_entry {
 		/*!< Pointer to function returning dynamic commands.*/
 		shell_dynamic_get dynamic_get;
 
@@ -73,7 +71,7 @@ struct shell_cmd_entry {
 
 struct shell;
 
-/*
+/**
  * @brief Shell command handler prototype.
  */
 typedef void (*shell_cmd_handler)(const struct shell *shell,
@@ -89,8 +87,7 @@ struct shell_static_entry {
 	shell_cmd_handler handler; /*!< Command handler. */
 };
 
-#define SHELL_CMD_NAME(name) UTIL_CAT(shell_cmd_, name)
+/**
-/*
  * @brief Macro for defining and adding a root command (level 0).
  *
  * @note Each root command shall have unique syntax.
@@ -111,7 +108,7 @@ struct shell_static_entry {
 		.u.entry = &UTIL_CAT(shell_, syntax)			   \
 	}
 
-/*
+/**
  * @brief Macro for creating a subcommand set. It must be used outside of any
  * function body.
  *
@@ -125,13 +122,13 @@ struct shell_static_entry {
 	};							\
 	static const struct shell_static_entry shell_##name[] =
 
-/*
+/**
  * @brief Define ending subcommands set.
  *
  */
 #define SHELL_SUBCMD_SET_END {NULL}
 
-/*
+/**
  * @brief Macro for creating a dynamic entry.
  *
  * @param[in] name  Name of the dynamic entry.
@@ -143,7 +140,7 @@ struct shell_static_entry {
 		.u.dynamic_get = get			\
 	}
 
-/*
+/**
  * @brief Initializes a shell command.
  *
  * @param[in] _syntax  Command syntax (for example: history).
@@ -158,7 +155,7 @@ struct shell_static_entry {
 	.handler = _handler				\
 }
 
-/*
+/**
  * @internal @brief Internal shell state in response to data received from the
  * terminal.
  */
@@ -170,7 +167,7 @@ enum shell_receive_state {
 };
 
 
-/*
+/**
  * @internal @brief Internal shell state.
  */
 enum shell_state {
@@ -181,7 +178,7 @@ enum shell_state {
 	SHELL_STATE_PANIC_MODE_INACTIVE /*!< Panic requested, not supported.*/
 };
 
-/* @brief Shell transport event. */
+/** @brief Shell transport event. */
 enum shell_transport_evt {
 	SHELL_TRANSPORT_EVT_RX_RDY,
 	SHELL_TRANSPORT_EVT_TX_RDY
@@ -192,11 +189,11 @@ typedef void (*shell_transport_handler_t)(enum shell_transport_evt evt,
 
 struct shell_transport;
 
-/*
+/**
  * @brief Unified shell transport interface.
  */
 struct shell_transport_api {
-	/*
+	/**
 	 * @brief Function for initializing the shell transport interface.
 	 *
 	 * @param[in] transport   Pointer to the transfer instance.
@@ -212,7 +209,7 @@ struct shell_transport_api {
 		    shell_transport_handler_t evt_handler,
 		    void *context);
 
-	/*
+	/**
 	 * @brief Function for uninitializing the shell transport interface.
 	 *
 	 * @param[in] transport  Pointer to the transfer instance.
@@ -221,7 +218,7 @@ struct shell_transport_api {
 	 */
 	int (*uninit)(const struct shell_transport *transport);
 
-	/*
+	/**
 	 * @brief Function for reconfiguring the transport to work in blocking
 	 * mode.
 	 *
@@ -233,7 +230,7 @@ struct shell_transport_api {
 	 */
 	int (*enable)(const struct shell_transport *transport, bool blocking);
 
-	/*
+	/**
 	 * @brief Function for writing data to the transport interface.
 	 *
 	 * @param[in] transport  Pointer to the transfer instance.
@@ -246,7 +243,7 @@ struct shell_transport_api {
 	int (*write)(const struct shell_transport *transport,
 		     const void *data, size_t length, size_t *cnt);
 
-	/*
+	/**
 	 * @brief Function for reading data from the transport interface.
 	 *
 	 * @param[in] p_transport  Pointer to the transfer instance.
@@ -266,7 +263,9 @@ struct shell_transport {
 	void *ctx;
 };
 
-/** @brief Shell statistics structure. */
+/**
+ * @brief Shell statistics structure.
+ */
 struct shell_stats {
 	u32_t log_lost_cnt; /*!< Lost log counter.*/
 };
@@ -279,7 +278,7 @@ struct shell_stats {
 #define SHELL_STATS_PTR(_name) NULL
 #endif /* CONFIG_SHELL_STATS */
 
-/*
+/**
  * @internal @brief Flags for internal shell usage.
  */
 struct shell_flags {
@@ -292,9 +291,11 @@ struct shell_flags {
 	u32_t mode_delete :1; /*!< Operation mode of backspace key */
 };
 
-BUILD_ASSERT(sizeof(struct shell_flags) == sizeof(u32_t));
+BUILD_ASSERT_MSG((sizeof(struct shell_flags) == sizeof(u32_t)),
+		 "Structure must fit in 4 bytes");
 
-/*
+
+/**
  * @internal @brief Union for internal shell usage.
  */
 union shell_internal {
@@ -310,7 +311,7 @@ enum shell_signal {
 	SHELL_SIGNALS
 };
 
-/*
+/**
  * @brief Shell instance context.
  */
 struct shell_ctx {
@@ -345,7 +346,7 @@ struct shell_ctx {
 
 extern const struct log_backend_api log_backend_shell_api;
 
-/*
+/**
  * @brief Shell instance internals.
  */
 struct shell {
@@ -371,7 +372,7 @@ struct shell {
 	k_thread_stack_t *stack;
 };
 
-/*
+/**
  * @brief Macro for defining a shell instance.
  *
  * @param[in] _name             Instance name.
@@ -411,7 +412,7 @@ struct shell {
 		.stack = _name##_stack					     \
 	}
 
-/*
+/**
  * @brief Function for initializing a transport layer and internal shell state.
  *
  * @param[in] shell            Pointer to shell instance.
@@ -426,7 +427,7 @@ struct shell {
 int shell_init(const struct shell *shell, const void *transport_config,
 	       bool use_colors, bool log_backend, u32_t init_log_level);
 
-/*
+/**
  * @brief Uninitializes the transport layer and the internal shell state.
  *
  * @param shell Pointer to shell instance.
@@ -435,7 +436,7 @@ int shell_init(const struct shell *shell, const void *transport_config,
  */
 int shell_uninit(const struct shell *shell);
 
-/*
+/**
  * @brief Function for starting shell processing.
  *
  * @param shell Pointer to the shell instance.
@@ -444,7 +445,7 @@ int shell_uninit(const struct shell *shell);
  */
 int shell_start(const struct shell *shell);
 
-/*
+/**
  * @brief Function for stopping shell processing.
  *
  * @param shell Pointer to shell instance.
@@ -453,16 +454,32 @@ int shell_start(const struct shell *shell);
  */
 int shell_stop(const struct shell *shell);
 
-/*
+/**
- * @brief Shell colors for nrf_shell_fprintf function.
+ * @brief Terminal default text color for nrf_shell_fprintf function.
  */
 #define SHELL_NORMAL	SHELL_VT100_COLOR_DEFAULT
+
+/**
+ * @brief Green text color for nrf_shell_fprintf function.
+ */
 #define SHELL_INFO	SHELL_VT100_COLOR_GREEN
+
+/**
+ * @brief Cyan text color for nrf_shell_fprintf function.
+ */
 #define SHELL_OPTION	SHELL_VT100_COLOR_CYAN
+
+/**
+ * @brief Yellow text color for nrf_shell_fprintf function.
+ */
 #define SHELL_WARNING	SHELL_VT100_COLOR_YELLOW
+
+/**
+ * @brief Red text color for nrf_shell_fprintf function.
+ */
 #define SHELL_ERROR	SHELL_VT100_COLOR_RED
 
-/*
+/**
  * @brief Printf-like function which sends formatted data stream to the shell.
  *	  This function shall not be used outside of the shell command context.
  *
@@ -474,7 +491,7 @@ int shell_stop(const struct shell *shell);
 void shell_fprintf(const struct shell *shell, enum shell_vt100_color color,
 		   const char *p_fmt, ...);
 
-/*
+/**
  * @brief Process function, which should be executed when data is ready in the
  *	  transport interface. To be used if shell thread is disabled.
  *
@@ -482,7 +499,7 @@ void shell_fprintf(const struct shell *shell, enum shell_vt100_color color,
  */
 void shell_process(const struct shell *shell);
 
-/*
+/**
  * @brief Option descriptor.
  */
 struct shell_getopt_option {
@@ -491,7 +508,7 @@ struct shell_getopt_option {
 	const char *optname_help; /*!< Option help string.*/
 };
 
-/*
+/**
  * @brief Option structure initializer.
  *
  * @param[in] _optname    Option name long.
@@ -504,7 +521,7 @@ struct shell_getopt_option {
 	.optname_help = _help,				\
 	}
 
-/*
+/**
  * @brief Informs that a command has been called with -h or --help option.
  *
  * @param[in] shell Pointer to the shell instance.
@@ -516,7 +533,7 @@ static inline bool shell_help_requested(const struct shell *shell)
 	return shell->ctx->internal.flags.show_help;
 }
 
-/*
+/**
  * @brief Prints the current command help.
  *
  * Function will print a help string with: the currently entered command, its
@@ -529,7 +546,7 @@ static inline bool shell_help_requested(const struct shell *shell)
 void shell_help_print(const struct shell *shell,
 		      const struct shell_getopt_option *opt, size_t opt_len);
 
-/*
+/**
  * @brief Change displayed shell prompt.
  *
  * @param[in] shell	Pointer to the shell instance.
@@ -540,10 +557,9 @@ void shell_help_print(const struct shell *shell,
  */
 int shell_prompt_change(const struct shell *shell, char *prompt);
 
-/*
+/**
- * @brief Prints help if request and prints error message on wrong argument
+ * @brief Prints help if requested and prints error message on wrong argument
  *	  count.
- *
  *	  Optionally, printing help on wrong argument count can be enabled.
  *
  * @param[in] shell	  Pointer to the shell instance.
@@ -554,11 +570,11 @@ int shell_prompt_change(const struct shell *shell, char *prompt);
  * @return True if check passed, false otherwise or help was requested.
  */
 bool shell_cmd_precheck(const struct shell *shell,
-			bool arg_cnt_nok,
+			bool arg_cnt_ok,
 			const struct shell_getopt_option *opt,
 			size_t opt_len);
 
-/*
+/**
  * @internal @brief This function shall not be used directly, it is required by
  *		    the fprintf module.
  *
@@ -569,7 +585,9 @@ bool shell_cmd_precheck(const struct shell *shell,
 void shell_print_stream(const void *user_ctx, const char *data,
 			size_t data_len);
 
-/* @} */
+/**
+ * @}
+ */
 
 #ifdef __cplusplus
 }