[PATCH v5 8/9] doc: rng: Add documentation for the rng command

[Sughosh Ganu]

Add a usage document for the 'rng' u-boot command.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
Reviewed-by: Simon Glass <sjg at chromium.org>
---

Changes since V4:

* Reflect the fact that a maximum of 64 bytes can be read on each
  invocation of the 'rng' command

 doc/usage/index.rst |  1 +
 doc/usage/rng.rst   | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 doc/usage/rng.rst

diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index 0aacf531b2..5712a924ae 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -45,6 +45,7 @@ Shell commands
    pstore
    qfw
    reset
+   rng
    sbi
    sf
    scp03
diff --git a/doc/usage/rng.rst b/doc/usage/rng.rst
new file mode 100644
index 0000000000..1a352da41a
--- /dev/null
+++ b/doc/usage/rng.rst
@@ -0,0 +1,26 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+rng command
+===========
+
+Synopsis
+--------
+
+::
+
+    rng [devnum [n]]
+
+Description
+-----------
+
+The *rng* command reads the random number generator(RNG) device and
+prints the random bytes read on the console. A maximum of 64 bytes can
+be read in one invocation of the command.
+
+devnum
+    The RNG device from which the random bytes are to be
+    read. Defaults to 0.
+
+n
+    Number of random bytes to be read and displayed on the
+    console. Default value is 0x40. Max value is 0x40.
-- 
2.25.1