diff --git a/include/libopencm3/stm32/can.h b/include/libopencm3/stm32/can.h
index 5d09da677f..81128f0741 100644
--- a/include/libopencm3/stm32/can.h
+++ b/include/libopencm3/stm32/can.h
@@ -649,18 +649,18 @@ int can_init(uint32_t canport, bool ttcm, bool abom, bool awum, bool nart,
 	     bool rflm, bool txfp, uint32_t sjw, uint32_t ts1, uint32_t ts2,
 	     uint32_t brp, bool loopback, bool silent);
 
-void can_filter_init(uint32_t canport, uint32_t nr, bool scale_32bit,
+void can_filter_init(uint32_t nr, bool scale_32bit,
 		     bool id_list_mode, uint32_t fr1, uint32_t fr2,
 		     uint32_t fifo, bool enable);
-void can_filter_id_mask_16bit_init(uint32_t canport, uint32_t nr, uint16_t id1,
+void can_filter_id_mask_16bit_init(uint32_t nr, uint16_t id1,
 				   uint16_t mask1, uint16_t id2,
 				   uint16_t mask2, uint32_t fifo, bool enable);
-void can_filter_id_mask_32bit_init(uint32_t canport, uint32_t nr, uint32_t id,
+void can_filter_id_mask_32bit_init(uint32_t nr, uint32_t id,
 				   uint32_t mask, uint32_t fifo, bool enable);
-void can_filter_id_list_16bit_init(uint32_t canport, uint32_t nr, uint16_t id1,
+void can_filter_id_list_16bit_init(uint32_t nr, uint16_t id1,
 				   uint16_t id2, uint16_t id3, uint16_t id4,
 				   uint32_t fifo, bool enable);
-void can_filter_id_list_32bit_init(uint32_t canport, uint32_t nr, uint32_t id1,
+void can_filter_id_list_32bit_init(uint32_t nr, uint32_t id1,
 				   uint32_t id2, uint32_t fifo, bool enable);
 
 void can_enable_irq(uint32_t canport, uint32_t irq);
diff --git a/lib/stm32/can.c b/lib/stm32/can.c
index a7ca00fd39..c9f16a1183 100644
--- a/lib/stm32/can.c
+++ b/lib/stm32/can.c
@@ -201,7 +201,6 @@ int can_init(uint32_t canport, bool ttcm, bool abom, bool awum, bool nart,
 
 Initialize incoming message filter and assign to FIFO.
 
-@param[in] canport Unsigned int32. CAN block register base @ref can_reg_base.
 @param[in] nr Unsigned int32. ID number of the filter.
 @param[in] scale_32bit bool. 32-bit scale for the filter?
 @param[in] id_list_mode bool. ID list filter mode?
@@ -210,59 +209,58 @@ Initialize incoming message filter and assign to FIFO.
 @param[in] fifo Unsigned int32. FIFO id.
 @param[in] enable bool. Enable filter?
  */
-void can_filter_init(uint32_t canport, uint32_t nr, bool scale_32bit,
+void can_filter_init(uint32_t nr, bool scale_32bit,
 		     bool id_list_mode, uint32_t fr1, uint32_t fr2,
 		     uint32_t fifo, bool enable)
 {
 	uint32_t filter_select_bit = 0x00000001 << nr;
 
 	/* Request initialization "enter". */
-	CAN_FMR(canport) |= CAN_FMR_FINIT;
+	CAN_FMR(CAN1) |= CAN_FMR_FINIT;
 
 	/* Deactivate the filter. */
-	CAN_FA1R(canport) &= ~filter_select_bit;
+	CAN_FA1R(CAN1) &= ~filter_select_bit;
 
 	if (scale_32bit) {
 		/* Set 32-bit scale for the filter. */
-		CAN_FS1R(canport) |= filter_select_bit;
+		CAN_FS1R(CAN1) |= filter_select_bit;
 	} else {
 		/* Set 16-bit scale for the filter. */
-		CAN_FS1R(canport) &= ~filter_select_bit;
+		CAN_FS1R(CAN1) &= ~filter_select_bit;
 	}
 
 	if (id_list_mode) {
 		/* Set filter mode to ID list mode. */
-		CAN_FM1R(canport) |= filter_select_bit;
+		CAN_FM1R(CAN1) |= filter_select_bit;
 	} else {
 		/* Set filter mode to id/mask mode. */
-		CAN_FM1R(canport) &= ~filter_select_bit;
+		CAN_FM1R(CAN1) &= ~filter_select_bit;
 	}
 
 	/* Set the first filter register. */
-	CAN_FiR1(canport, nr) = fr1;
+	CAN_FiR1(CAN1, nr) = fr1;
 
 	/* Set the second filter register. */
-	CAN_FiR2(canport, nr) = fr2;
+	CAN_FiR2(CAN1, nr) = fr2;
 
 	/* Select FIFO0 or FIFO1 as filter assignement. */
 	if (fifo) {
-		CAN_FFA1R(canport) |= filter_select_bit;  /* FIFO1 */
+		CAN_FFA1R(CAN1) |= filter_select_bit;  /* FIFO1 */
 	} else {
-		CAN_FFA1R(canport) &= ~filter_select_bit; /* FIFO0 */
+		CAN_FFA1R(CAN1) &= ~filter_select_bit; /* FIFO0 */
 	}
 
 	if (enable) {
-		CAN_FA1R(canport) |= filter_select_bit; /* Activate filter. */
+		CAN_FA1R(CAN1) |= filter_select_bit; /* Activate filter. */
 	}
 
 	/* Request initialization "leave". */
-	CAN_FMR(canport) &= ~CAN_FMR_FINIT;
+	CAN_FMR(CAN1) &= ~CAN_FMR_FINIT;
 }
 
 /*---------------------------------------------------------------------------*/
 /** @brief CAN Initialize a 16bit Message ID Mask Filter
 
-@param[in] canport Unsigned int32. CAN block register base @ref can_reg_base.
 @param[in] nr Unsigned int32. ID number of the filter.
 @param[in] id1 Unsigned int16. First message ID to filter.
 @param[in] mask1 Unsigned int16. First message ID bit mask.
@@ -271,11 +269,11 @@ void can_filter_init(uint32_t canport, uint32_t nr, bool scale_32bit,
 @param[in] fifo Unsigned int32. FIFO id.
 @param[in] enable bool. Enable filter?
  */
-void can_filter_id_mask_16bit_init(uint32_t canport, uint32_t nr, uint16_t id1,
+void can_filter_id_mask_16bit_init(uint32_t nr, uint16_t id1,
 				   uint16_t mask1, uint16_t id2,
 				   uint16_t mask2, uint32_t fifo, bool enable)
 {
-	can_filter_init(canport, nr, false, false,
+	can_filter_init(nr, false, false,
 			((uint32_t)id1 << 16) | (uint32_t)mask1,
 			((uint32_t)id2 << 16) | (uint32_t)mask2, fifo, enable);
 }
@@ -283,23 +281,21 @@ void can_filter_id_mask_16bit_init(uint32_t canport, uint32_t nr, uint16_t id1,
 /*---------------------------------------------------------------------------*/
 /** @brief CAN Initialize a 32bit Message ID Mask Filter
 
-@param[in] canport Unsigned int32. CAN block register base @ref can_reg_base.
 @param[in] nr Unsigned int32. ID number of the filter.
 @param[in] id Unsigned int32. Message ID to filter.
 @param[in] mask Unsigned int32. Message ID bit mask.
 @param[in] fifo Unsigned int32. FIFO id.
 @param[in] enable bool. Enable filter?
  */
-void can_filter_id_mask_32bit_init(uint32_t canport, uint32_t nr, uint32_t id,
+void can_filter_id_mask_32bit_init(uint32_t nr, uint32_t id,
 				   uint32_t mask, uint32_t fifo, bool enable)
 {
-	can_filter_init(canport, nr, true, false, id, mask, fifo, enable);
+	can_filter_init(nr, true, false, id, mask, fifo, enable);
 }
 
 /*---------------------------------------------------------------------------*/
 /** @brief CAN Initialize a 16bit Message ID List Filter
 
-@param[in] canport Unsigned int32. CAN block register base @ref can_reg_base.
 @param[in] nr Unsigned int32. ID number of the filter.
 @param[in] id1 Unsigned int16. First message ID to match.
 @param[in] id2 Unsigned int16. Second message ID to match.
@@ -308,12 +304,12 @@ void can_filter_id_mask_32bit_init(uint32_t canport, uint32_t nr, uint32_t id,
 @param[in] fifo Unsigned int32. FIFO id.
 @param[in] enable bool. Enable filter?
  */
-void can_filter_id_list_16bit_init(uint32_t canport, uint32_t nr,
+void can_filter_id_list_16bit_init(uint32_t nr,
 				   uint16_t id1, uint16_t id2,
 				   uint16_t id3, uint16_t id4,
 				   uint32_t fifo, bool enable)
 {
-	can_filter_init(canport, nr, false, true,
+	can_filter_init(nr, false, true,
 			((uint32_t)id1 << 16) | (uint32_t)id2,
 			((uint32_t)id3 << 16) | (uint32_t)id4, fifo, enable);
 }
@@ -321,18 +317,17 @@ void can_filter_id_list_16bit_init(uint32_t canport, uint32_t nr,
 /*---------------------------------------------------------------------------*/
 /** @brief CAN Initialize a 32bit Message ID List Filter
 
-@param[in] canport Unsigned int32. CAN block register base @ref can_reg_base.
 @param[in] nr Unsigned int32. ID number of the filter.
 @param[in] id1 Unsigned int32. First message ID to match.
 @param[in] id2 Unsigned int32. Second message ID to match.
 @param[in] fifo Unsigned int32. FIFO id.
 @param[in] enable bool. Enable filter?
  */
-void can_filter_id_list_32bit_init(uint32_t canport, uint32_t nr,
+void can_filter_id_list_32bit_init(uint32_t nr,
 				   uint32_t id1, uint32_t id2,
 				   uint32_t fifo, bool enable)
 {
-	can_filter_init(canport, nr, true, true, id1, id2, fifo, enable);
+	can_filter_init(nr, true, true, id1, id2, fifo, enable);
 }
 
 /*---------------------------------------------------------------------------*/