diff --git a/include/libopencm3/stm32/common/dmamux_common_all.h b/include/libopencm3/stm32/common/dmamux_common_all.h
index c3bd0bf7..f8b1a528 100644
--- a/include/libopencm3/stm32/common/dmamux_common_all.h
+++ b/include/libopencm3/stm32/common/dmamux_common_all.h
@@ -25,11 +25,7 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-/** @cond */
-#if defined(LIBOPENCM3_DMAMUX_H)
-/** @endcond */
-#ifndef LIBOPENCM3_DMAMUX_COMMON_ALL_H
-#define LIBOPENCM3_DMAMUX_COMMON_ALL_H
+#pragma once
 
 /**@{*/
 
@@ -205,10 +201,3 @@ void dmamux_clear_request_generator_trigger_overrun_interrupt(uint32_t dmamux, u
 END_DECLS
 
 /**@}*/
-
-#endif
-/** @cond */
-#else
-#warning "dmamux_common_all.h should not be included explicitly, only via dmamux.h"
-#endif
-/** @endcond */
diff --git a/include/libopencm3/stm32/common/timer_common_all.h b/include/libopencm3/stm32/common/timer_common_all.h
index c3b8c048..08939d90 100644
--- a/include/libopencm3/stm32/common/timer_common_all.h
+++ b/include/libopencm3/stm32/common/timer_common_all.h
@@ -28,12 +28,7 @@
 The order of header inclusion is important. timer.h includes the device
 specific memorymap.h header before including this header file.*/
 
-/** @cond */
-#if defined(LIBOPENCM3_TIMER_H)
-/** @endcond */
-#ifndef LIBOPENCM3_TIMER_COMMON_H
-#define LIBOPENCM3_TIMER_COMMON_H
-
+#pragma once
 /* --- Convenience macros -------------------------------------------------- */
 
 /* Timer register base addresses (for convenience) */
@@ -1241,10 +1236,4 @@ void timer_slave_set_trigger(uint32_t timer, uint8_t trigger);
 
 END_DECLS
 
-#endif
-/** @cond */
-#else
-#warning "timer_common_all.h should not be included directly, only via timer.h"
-#endif
-/** @endcond */
 /**@}*/
diff --git a/include/libopencm3/stm32/common/timer_common_f24.h b/include/libopencm3/stm32/common/timer_common_f24.h
index 6f483d86..2d9c98ad 100644
--- a/include/libopencm3/stm32/common/timer_common_f24.h
+++ b/include/libopencm3/stm32/common/timer_common_f24.h
@@ -27,12 +27,7 @@
 The order of header inclusion is important. timer.h includes the device
 specific memorymap.h header before including this header file.*/
 
-/** @cond */
-#ifdef LIBOPENCM3_TIMER_H
-/** @endcond */
-#ifndef LIBOPENCM3_TIMER_COMMON_F24_H
-#define LIBOPENCM3_TIMER_COMMON_F24_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
 
 /*
@@ -104,11 +99,3 @@ void timer_ic_set_polarity(uint32_t timer, enum tim_ic_id ic,
 			   enum tim_ic_pol pol);
 
 END_DECLS
-
-#endif
-/** @cond */
-#else
-#warning "timer_common_f24.h should not be included directly, only via timer.h"
-#endif
-/** @endcond */
-
diff --git a/include/libopencm3/stm32/f0/timer.h b/include/libopencm3/stm32/f0/timer.h
index 5f59816c..2f5aea27 100644
--- a/include/libopencm3/stm32/f0/timer.h
+++ b/include/libopencm3/stm32/f0/timer.h
@@ -29,9 +29,6 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
+#pragma once
 
 #include <libopencm3/stm32/common/timer_common_f24.h>
-
-#endif
diff --git a/include/libopencm3/stm32/f1/timer.h b/include/libopencm3/stm32/f1/timer.h
index 6046d792..018c9c2e 100644
--- a/include/libopencm3/stm32/f1/timer.h
+++ b/include/libopencm3/stm32/f1/timer.h
@@ -32,8 +32,7 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
+#pragma once
 
 #include <libopencm3/stm32/common/timer_common_all.h>
 
@@ -52,5 +51,3 @@ void timer_ic_set_polarity(uint32_t timer,
 			   enum tim_ic_pol pol);
 
 END_DECLS
-
-#endif
diff --git a/include/libopencm3/stm32/f2/timer.h b/include/libopencm3/stm32/f2/timer.h
index 7dc6d326..ad88dcff 100644
--- a/include/libopencm3/stm32/f2/timer.h
+++ b/include/libopencm3/stm32/f2/timer.h
@@ -31,9 +31,5 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_f24.h>
-
-#endif
diff --git a/include/libopencm3/stm32/f3/timer.h b/include/libopencm3/stm32/f3/timer.h
index f9284c7e..1201ec83 100644
--- a/include/libopencm3/stm32/f3/timer.h
+++ b/include/libopencm3/stm32/f3/timer.h
@@ -31,9 +31,5 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_f24.h>
-
-#endif
diff --git a/include/libopencm3/stm32/f4/timer.h b/include/libopencm3/stm32/f4/timer.h
index 604a83f3..1155e8ed 100644
--- a/include/libopencm3/stm32/f4/timer.h
+++ b/include/libopencm3/stm32/f4/timer.h
@@ -31,9 +31,5 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_f24.h>
-
-#endif
diff --git a/include/libopencm3/stm32/f7/timer.h b/include/libopencm3/stm32/f7/timer.h
index da890943..0ebd4a4b 100644
--- a/include/libopencm3/stm32/f7/timer.h
+++ b/include/libopencm3/stm32/f7/timer.h
@@ -30,13 +30,5 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
-
-BEGIN_DECLS
-
-END_DECLS
-
-#endif
diff --git a/include/libopencm3/stm32/g0/dmamux.h b/include/libopencm3/stm32/g0/dmamux.h
index 27775344..6306d656 100644
--- a/include/libopencm3/stm32/g0/dmamux.h
+++ b/include/libopencm3/stm32/g0/dmamux.h
@@ -29,8 +29,7 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_DMAMUX_H
-#define LIBOPENCM3_DMAMUX_H
+#pragma once
 /**@{*/
 
 #include <libopencm3/stm32/common/dmamux_common_all.h>
@@ -169,4 +168,3 @@
 /**@}*/
 
 /**@}*/
-#endif
diff --git a/include/libopencm3/stm32/g0/timer.h b/include/libopencm3/stm32/g0/timer.h
index 1f102ba8..0b4dd226 100644
--- a/include/libopencm3/stm32/g0/timer.h
+++ b/include/libopencm3/stm32/g0/timer.h
@@ -27,9 +27,7 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
 
 /**@{*/
@@ -70,5 +68,3 @@ BEGIN_DECLS
 END_DECLS
 
 /**@}*/
-
-#endif
diff --git a/include/libopencm3/stm32/g4/timer.h b/include/libopencm3/stm32/g4/timer.h
index 06a661c7..3cf831f6 100644
--- a/include/libopencm3/stm32/g4/timer.h
+++ b/include/libopencm3/stm32/g4/timer.h
@@ -27,9 +27,5 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_f24.h>
-
-#endif
diff --git a/include/libopencm3/stm32/h7/timer.h b/include/libopencm3/stm32/h7/timer.h
index 62a636a4..049cb49c 100644
--- a/include/libopencm3/stm32/h7/timer.h
+++ b/include/libopencm3/stm32/h7/timer.h
@@ -21,13 +21,5 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
-
-BEGIN_DECLS
-
-END_DECLS
-
-#endif
diff --git a/include/libopencm3/stm32/l0/timer.h b/include/libopencm3/stm32/l0/timer.h
index 1c6eb524..5e77059d 100644
--- a/include/libopencm3/stm32/l0/timer.h
+++ b/include/libopencm3/stm32/l0/timer.h
@@ -33,7 +33,6 @@ LGPL License Terms @ref lgpl_license
  */
 
 #pragma once
-
 #include <libopencm3/stm32/common/timer_common_all.h>
 
 /**@{*/
@@ -96,4 +95,3 @@ LGPL License Terms @ref lgpl_license
 #define TIM22_OR_TI1_RMP_COMP1_OUT	(2 << TIM22_OR_TI1_RMP_SHIFT)
 
 /**@}*/
-
diff --git a/include/libopencm3/stm32/l1/timer.h b/include/libopencm3/stm32/l1/timer.h
index faef4346..fe1c0893 100644
--- a/include/libopencm3/stm32/l1/timer.h
+++ b/include/libopencm3/stm32/l1/timer.h
@@ -32,9 +32,7 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
 
 /**@{*/
@@ -84,5 +82,3 @@ void timer_set_option(uint32_t timer_peripheral, uint32_t option);
 END_DECLS
 
 /**@}*/
-
-#endif
diff --git a/include/libopencm3/stm32/l4/timer.h b/include/libopencm3/stm32/l4/timer.h
index 355c1ca1..2486172b 100644
--- a/include/libopencm3/stm32/l4/timer.h
+++ b/include/libopencm3/stm32/l4/timer.h
@@ -32,13 +32,5 @@ LGPL License Terms @ref lgpl_license
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef LIBOPENCM3_TIMER_H
-#define LIBOPENCM3_TIMER_H
-
+#pragma once
 #include <libopencm3/stm32/common/timer_common_all.h>
-
-BEGIN_DECLS
-
-END_DECLS
-
-#endif