From 84f8156605650fae653ce1402ad3857af5d2bf2f Mon Sep 17 00:00:00 2001
From: hanzhijian <hanzhijian@zepp.com>
Date: Tue, 26 May 2026 10:10:22 +0800
Subject: [PATCH] Documentation: document uniqueid command.

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
---
 .../applications/system/uniqueid/index.rst    | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/Documentation/applications/system/uniqueid/index.rst b/Documentation/applications/system/uniqueid/index.rst
index b3b204f59a7..f78d81b8f96 100644
--- a/Documentation/applications/system/uniqueid/index.rst
+++ b/Documentation/applications/system/uniqueid/index.rst
@@ -1,3 +1,80 @@
 ===============================
 ``uniqueid`` "uniqueid" command
 ===============================
+
+Overview
+========
+
+The ``uniqueid`` command prints the board unique ID returned by the
+``BOARDIOC_UNIQUEID`` ``boardctl()`` command.  It is useful for checking the
+identifier that board-specific logic exposes through ``board_uniqueid()`` and
+for formatting selected bytes of that identifier from NSH scripts.
+
+Configuration
+=============
+
+Enable the command with ``CONFIG_SYSTEM_UNIQUEID``.  This option depends on
+``CONFIG_BOARDCTL_UNIQUEID`` because the board must provide the
+``BOARDIOC_UNIQUEID`` implementation.  The number of bytes printed by default
+is controlled by ``CONFIG_BOARDCTL_UNIQUEID_SIZE``.
+
+Usage
+=====
+
+.. code-block:: console
+
+   uniqueid [-b <bytes>] [-d <delimiter>] [-f <format>] [-p <prefix>]
+
+When ``-b`` is omitted, ``uniqueid`` prints all
+``CONFIG_BOARDCTL_UNIQUEID_SIZE`` bytes.
+
+Options
+=======
+
+``-b <bytes>``
+  Select the bytes to print.  Byte positions are one-based and may be provided
+  as a comma-separated list, ranges, or a mix of both.  Ranges may be ascending
+  or descending, for example ``1,2,4-8`` or ``8-1``.
+
+``-d <delimiter>``
+  Print ``<delimiter>`` between selected bytes.
+
+``-f <format>``
+  Format each byte with the supplied ``printf`` conversion suffix.  The default
+  is ``02x``.  The command accepts integer and character conversions ending in
+  ``d``, ``i``, ``o``, ``u``, ``x``, ``X``, or ``c``.
+
+``-p <prefix>``
+  Print ``<prefix>`` before the first byte.
+
+Examples
+========
+
+Print the full unique ID as hexadecimal bytes without separators:
+
+.. code-block:: console
+
+   nsh> uniqueid
+   00112233445566778899aabbccddeeff
+
+Print the ID as colon-separated hexadecimal bytes:
+
+.. code-block:: console
+
+   nsh> uniqueid -d :
+   00:11:22:33:44:55:66:77:88:99:aa:bb:cc:dd:ee:ff
+
+Print only the first four bytes with a prefix:
+
+.. code-block:: console
+
+   nsh> uniqueid -b 1-4 -d : -p uid:
+   uid:00:11:22:33
+
+Notes
+=====
+
+The actual unique ID value and its stability across resets or boards are
+provided by the board-specific ``board_uniqueid()`` implementation.  If the
+board does not implement ``BOARDIOC_UNIQUEID``, the command reports an error
+from ``boardctl()``.