diff --git a/share/man/man4/man4.riscv64/Makefile b/share/man/man4/man4.riscv64/Makefile
index bca5ab0ae7f..9e7d0076c23 100644
--- a/share/man/man4/man4.riscv64/Makefile
+++ b/share/man/man4/man4.riscv64/Makefile
@@ -1,7 +1,8 @@
-#	$OpenBSD: Makefile,v 1.12 2025/12/02 20:03:19 kettenis Exp $
+#	$OpenBSD: Makefile,v 1.13 2026/04/04 14:12:50 kettenis Exp $
 
 MAN=	intro.4 mpfclock.4 mpfgpio.4 mpfiic.4 plic.4 \
 	sfcc.4 sfclock.4 sfgpio.4 sfuart.4 sgmsi.4 \
+	smtgpio.4 \
 	stfclock.4 stfpcie.4 stfpciephy.4 stfpinctrl.4 stfrng.4
 
 MANSUBDIR=riscv64
diff --git a/share/man/man4/man4.riscv64/smtgpio.4 b/share/man/man4/man4.riscv64/smtgpio.4
new file mode 100644
index 00000000000..a46d6452f4f
--- /dev/null
+++ b/share/man/man4/man4.riscv64/smtgpio.4
@@ -0,0 +1,43 @@
+.\"	$OpenBSD: smtgpio.4,v 1.1 2026/04/04 14:12:50 kettenis Exp $
+.\"
+.\" Copyright (c) 2026 Mark Kettenis <kettenis@openbsd.org>
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: April 4 2026 $
+.Dt SMTGPIO 4 riscv64
+.Os
+.Sh NAME
+.Nm smtgpio
+.Nd SpacemiT GPIO controller
+.Sh SYNOPSIS
+.Cd "smtgpio* at fdt?"
+.Sh DESCRIPTION
+The
+.Nm
+driver provides support for the GPIO controller found on SpacemiT SoCs.
+It does not provide direct device driver entry points but makes its
+functions available to other drivers.
+.Sh SEE ALSO
+.Xr intro 4
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Ox 7.9 .
+.Sh AUTHORS
+.An -nosplit
+The
+.Nm
+driver was written by
+.An Mark Kettenis Aq Mt kettenis@openbsd.org .