diff --git a/arch/arm/src/samd/chip/sam_pm.h b/arch/arm/src/samd/chip/sam_pm.h
index 67f1d6b370d..226c9121c39 100644
--- a/arch/arm/src/samd/chip/sam_pm.h
+++ b/arch/arm/src/samd/chip/sam_pm.h
@@ -181,11 +181,12 @@
 
 #define PM_APBCMASK_PAC2          (1 << 0)  /* Bit 0:  PAC2 */
 #define PM_APBCMASK_EVSYS         (1 << 1)  /* Bit 1:  EVSYS */
-#define PM_APBCMASK_SERCOM0       (1 << 2)  /* Bit 2:  SERCOM0 */
-#define PM_APBCMASK_SERCOM1       (1 << 3)  /* Bit 3:  SERCOM1 */
-#define PM_APBCMASK_SERCOM2       (1 << 4)  /* Bit 4:  SERCOM2 */
-#define PM_APBCMASK_SERCOM3       (1 << 5)  /* Bit 5:  SERCOM3 */
-#define PM_APBCMASK_SERCOM4       (1 << 6)  /* Bit 6:  SERCOM4 */
+#define PM_APBCMASK_SERCOM(n)     (1 << ((n)+2))
+#  define PM_APBCMASK_SERCOM0     (1 << 2)  /* Bit 2:  SERCOM0 */
+#  define PM_APBCMASK_SERCOM1     (1 << 3)  /* Bit 3:  SERCOM1 */
+#  define PM_APBCMASK_SERCOM2     (1 << 4)  /* Bit 4:  SERCOM2 */
+#  define PM_APBCMASK_SERCOM3     (1 << 5)  /* Bit 5:  SERCOM3 */
+#  define PM_APBCMASK_SERCOM4     (1 << 6)  /* Bit 6:  SERCOM4 */
 #define PM_APBCMASK_SERCOM5       (1 << 7)  /* Bit 7:  SERCOM5 */
 #define PM_APBCMASK_TC0           (1 << 8)  /* Bit 8:  TC0 */
 #define PM_APBCMASK_TC1           (1 << 9)  /* Bit 9:  TC1 */
diff --git a/arch/arm/src/samd/sam_usart.c b/arch/arm/src/samd/sam_usart.c
index 2d3fe86b351..2d9180eb985 100644
--- a/arch/arm/src/samd/sam_usart.c
+++ b/arch/arm/src/samd/sam_usart.c
@@ -43,6 +43,7 @@
 #include <assert.h>
 
 #include "chip/sam_pinmap.h"
+#include "chip/sam_gclk.h"
 #include "chip/sam_usart.h"
 
 #include <arch/board/board.h>
@@ -64,6 +65,7 @@ const struct sam_usart_config_s g_usart0config =
   .parity    = CONFIG_USART0_PARITY,
   .bits      = CONFIG_USART0_BITS,
   .irq       = SAM_IRQ_SERCOM0,
+  .gclk      = (BOARD_SERCOM0_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART0_2STOP,
   .baud      = CONFIG_USART0_BAUD,
   .pad0      = BOARD_SERCOM0_PINMAP_PAD0,
@@ -82,6 +84,7 @@ const struct sam_usart_config_s g_usart1config =
   .parity    = CONFIG_USART1_PARITY,
   .bits      = CONFIG_USART1_BITS,
   .irq       = SAM_IRQ_SERCOM1,
+  .gclk      = (BOARD_SERCOM1_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART1_2STOP,
   .baud      = CONFIG_USART1_BAUD,
   .pad0      = BOARD_SERCOM1_PINMAP_PAD0,
@@ -100,6 +103,7 @@ const struct sam_usart_config_s g_usart2config =
   .parity    = CONFIG_USART2_PARITY,
   .bits      = CONFIG_USART2_BITS,
   .irq       = SAM_IRQ_SERCOM2,
+  .gclk      = (BOARD_SERCOM2_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART2_2STOP,
   .baud      = CONFIG_USART2_BAUD,
   .pad0      = BOARD_SERCOM2_PINMAP_PAD0,
@@ -118,6 +122,7 @@ const struct sam_usart_config_s g_usart3config =
   .parity    = CONFIG_USART3_PARITY,
   .bits      = CONFIG_USART3_BITS,
   .irq       = SAM_IRQ_SERCOM3,
+  .gclk      = (BOARD_SERCOM3_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART3_2STOP,
   .baud      = CONFIG_USART3_BAUD,
   .pad0      = BOARD_SERCOM3_PINMAP_PAD0,
@@ -136,6 +141,7 @@ const struct sam_usart_config_s g_usart4config =
   .parity    = CONFIG_USART4_PARITY,
   .bits      = CONFIG_USART4_BITS,
   .irq       = SAM_IRQ_SERCOM4,
+  .gclk      = (BOARD_SERCOM4_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART4_2STOP,
   .baud      = CONFIG_USART4_BAUD,
   .pad0      = BOARD_SERCOM4_PINMAP_PAD0,
@@ -154,6 +160,7 @@ const struct sam_usart_config_s g_usart5config =
   .parity    = CONFIG_USART5_PARITY,
   .bits      = CONFIG_USART5_BITS,
   .irq       = SAM_IRQ_SERCOM5,
+  .gclk      = (BOARD_SERCOM5_SRCGCLKGEN >> GCLK_CLKCTRL_GEN_SHIFT),
   .stopbits2 = CONFIG_USART5_2STOP,
   .baud      = CONFIG_USART5_BAUD,
   .pad0      = BOARD_SERCOM5_PINMAP_PAD0,
diff --git a/arch/arm/src/samd/sam_usart.h b/arch/arm/src/samd/sam_usart.h
index a8585ae2d2d..b61a45b46aa 100644
--- a/arch/arm/src/samd/sam_usart.h
+++ b/arch/arm/src/samd/sam_usart.h
@@ -82,6 +82,7 @@ struct sam_usart_config_s
   uint8_t parity;     /* 0=none, 1=odd, 2=even */
   uint8_t bits;       /* Number of bits (5-9) */
   uint8_t irq;        /* SERCOM IRQ number */
+  uint8_t gclk;       /* Source GCLK generator */
   bool isconsole;     /* True: The USART is the console device */
   bool stopbits2;     /* True: Configure with 2 stop bits instead of 1 */
   uint32_t baud;      /* Configured baud */