diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 2e8134059c87..6655d929a351 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -104,6 +104,7 @@ Code  Seq#    Include File                                           Comments
 '8'   all                                                            SNP8023 advanced NIC card
                                                                      <mailto:mcr@solidum.com>
 ';'   64-7F  linux/vfio.h
+'='   00-3f  uapi/linux/ptp_clock.h                                  <mailto:richardcochran@gmail.com>
 '@'   00-0F  linux/radeonfb.h                                        conflict!
 '@'   00-0F  drivers/video/aty/aty128fb.c                            conflict!
 'A'   00-1F  linux/apm_bios.h                                        conflict!