This patch adds support for decoding hex input, so
that binary attributes can be read through --json.

Example (using future wireguard.yaml):
 $ sudo ./tools/net/ynl/pyynl/cli.py --family wireguard \
   --do set-device --json '{"ifindex":3,
     "private-key":"2a ae 6c 35 c9 4f cf <... to 32 bytes>"}'

In order to somewhat mirror what is done in _formatted_string(),
then for non-binary attributes attempt to convert it to an int.

Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
---
 tools/net/ynl/pyynl/lib/ynl.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/net/ynl/pyynl/lib/ynl.py b/tools/net/ynl/pyynl/lib/ynl.py
index 9fd83f8b091f..707753e371e2 100644
--- a/tools/net/ynl/pyynl/lib/ynl.py
+++ b/tools/net/ynl/pyynl/lib/ynl.py
@@ -971,6 +971,11 @@ class YnlFamily(SpecFamily):
                 raw = ip.packed
             else:
                 raw = int(ip)
+        elif attr_spec.display_hint == 'hex':
+            if attr_spec['type'] == 'binary':
+                raw = bytes.fromhex(string)
+            else:
+                raw = int(string, 16)
         else:
             raise Exception(f"Display hint '{attr_spec.display_hint}' not implemented"
                             f" when parsing '{attr_spec['name']}'")
-- 
2.51.0