[PATCH v3 04/11] binman: doc: Add documentation for fdt_add_pubkey bintool

[lukas.funke-oss at weidmueller.com]

From: Lukas Funke <lukas.funke at weidmueller.com>

Add documentation for btool which calls 'fdt_add_pubkey'

Signed-off-by: Lukas Funke <lukas.funke at weidmueller.com>
Reviewed-by: Simon Glass <sjg at chromium.org>

---

Changes in v3:
- Fix rst headline length

 tools/binman/bintools.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/binman/bintools.rst b/tools/binman/bintools.rst
index c30e7eb9ff..0c5d510886 100644
--- a/tools/binman/bintools.rst
+++ b/tools/binman/bintools.rst
@@ -183,3 +183,13 @@ Documentation is available via::
 
 
 
+Bintool: fdt_add_pubkey: Add public key to device tree
+------------------------------------------------------
+
+This bintool supports running `fdt_add_pubkey` in order to add a public
+key coming from a certificate to a device-tree.
+
+Normally signing is done using `mkimage` in context of `binman sign`. However,
+in this process the public key is not added to the stage before u-boot proper.
+Using `fdt_add_pubkey` the key can be injected to the SPL independent of
+`mkimage`
-- 
2.30.2