diff --git a/boards/msbiot/include/periph_conf.h b/boards/msbiot/include/periph_conf.h
index 46db99dae6..c302db7509 100644
--- a/boards/msbiot/include/periph_conf.h
+++ b/boards/msbiot/include/periph_conf.h
@@ -198,97 +198,97 @@ extern "C" {
 /* GPIO channel 0 config */
 #define GPIO_0_PORT         GPIOA                   /* User Button 2 */
 #define GPIO_0_PIN          0
-#define GPIO_0_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN)
+#define GPIO_0_CLK          0                       /* 0: PORT A, 1: B ... */
 #define GPIO_0_EXTI_CFG()   (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI0_PA)
 #define GPIO_0_IRQ          EXTI0_IRQn
 /* GPIO channel 1 config */
 #define GPIO_1_PORT         GPIOA
 #define GPIO_1_PIN          1
-#define GPIO_1_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN)
+#define GPIO_1_CLK          0
 #define GPIO_1_EXTI_CFG()   (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI1_PA)
 #define GPIO_1_IRQ          EXTI1_IRQn
 /* GPIO channel 2 config */
 #define GPIO_2_PORT         GPIOA                   /* CC1101 GDO1 */
 #define GPIO_2_PIN          6
-#define GPIO_2_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN)
+#define GPIO_2_CLK          0
 #define GPIO_2_EXTI_CFG()   (SYSCFG->EXTICR[1] |= SYSCFG_EXTICR2_EXTI6_PA)
 #define GPIO_2_IRQ          EXTI9_5_IRQn
 /* GPIO channel 3 config */
 #define GPIO_3_PORT         GPIOA                   /* CC3000 SPI_IRQ */
 #define GPIO_3_PIN          10
-#define GPIO_3_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN)
+#define GPIO_3_CLK          0
 #define GPIO_3_EXTI_CFG()   (SYSCFG->EXTICR[2] |= SYSCFG_EXTICR3_EXTI10_PA)
 #define GPIO_3_IRQ          EXTI15_10_IRQn
 /* GPIO channel 4 config */
 #define GPIO_4_PORT         GPIOB
 #define GPIO_4_PIN          0
-#define GPIO_4_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN)
+#define GPIO_4_CLK          1
 #define GPIO_4_EXTI_CFG()   (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI0_PB)
 #define GPIO_4_IRQ          EXTI0_IRQn
 /* GPIO channel 5 config */
 #define GPIO_5_PORT         GPIOB                   /* BEEPER Input */
 #define GPIO_5_PIN          9
-#define GPIO_5_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN)
+#define GPIO_5_CLK          1
 #define GPIO_5_EXTI_CFG()   (SYSCFG->EXTICR[2] |= SYSCFG_EXTICR3_EXTI9_PB)
 #define GPIO_5_IRQ          EXTI9_5_IRQn
 /* GPIO channel 6 config */
 #define GPIO_6_PORT         GPIOB                   /* IMU-9150 INT */
 #define GPIO_6_PIN          11
-#define GPIO_6_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN)
+#define GPIO_6_CLK          1
 #define GPIO_6_EXTI_CFG()   (SYSCFG->EXTICR[2] |= SYSCFG_EXTICR3_EXTI11_PB)
 #define GPIO_6_IRQ          EXTI15_10_IRQn
 /* GPIO channel 7 config */
 #define GPIO_7_PORT         GPIOB                   /* CC1101 CS */
 #define GPIO_7_PIN          12
-#define GPIO_7_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN)
+#define GPIO_7_CLK          1
 #define GPIO_7_EXTI_CFG()   (SYSCFG->EXTICR[3] |= SYSCFG_EXTICR4_EXTI12_PB)
 #define GPIO_7_IRQ          EXTI15_10_IRQn
 /* GPIO channel 8 config */
 #define GPIO_8_PORT         GPIOB                   /* User Button 1 */
 #define GPIO_8_PIN          13
-#define GPIO_8_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN)
+#define GPIO_8_CLK          1
 #define GPIO_8_EXTI_CFG()   (SYSCFG->EXTICR[3] |= SYSCFG_EXTICR4_EXTI13_PB)
 #define GPIO_8_IRQ          EXTI15_10_IRQn
 /* GPIO channel 9 config */
 #define GPIO_9_PORT         GPIOC                   /* TCA6416 Reset */
 #define GPIO_9_PIN          0
-#define GPIO_9_CLKEN()      (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_9_CLK          2
 #define GPIO_9_EXTI_CFG()   (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI0_PC)
 #define GPIO_9_IRQ          EXTI0_IRQn
 /* GPIO channel 10 config */
 #define GPIO_10_PORT        GPIOC                   /* CC3000 CS */
 #define GPIO_10_PIN         1
-#define GPIO_10_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_10_CLK         2
 #define GPIO_10_EXTI_CFG()  (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI1_PC)
 #define GPIO_10_IRQ         EXTI1_IRQn
 /* GPIO channel 11 config */
 #define GPIO_11_PORT        GPIOC                   /* CC1101 GDO 0 */
 #define GPIO_11_PIN         4
-#define GPIO_11_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_11_CLK         2
 #define GPIO_11_EXTI_CFG()  (SYSCFG->EXTICR[1] |= SYSCFG_EXTICR2_EXTI4_PC)
 #define GPIO_11_IRQ         EXTI4_IRQn
 /* GPIO channel 12 config */
 #define GPIO_12_PORT        GPIOC                   /* CC1101 GDO 2 */
 #define GPIO_12_PIN         5
-#define GPIO_12_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_12_CLK         2
 #define GPIO_12_EXTI_CFG()  (SYSCFG->EXTICR[1] |= SYSCFG_EXTICR2_EXTI5_PC)
 #define GPIO_12_IRQ         EXTI9_5_IRQn
 /* GPIO channel 13 config */
 #define GPIO_13_PORT        GPIOC                   /* TCA6416 INT */
 #define GPIO_13_PIN         8
-#define GPIO_13_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_13_CLK         2
 #define GPIO_13_EXTI_CFG()  (SYSCFG->EXTICR[2] |= SYSCFG_EXTICR3_EXTI8_PC)
 #define GPIO_13_IRQ         EXTI9_5_IRQn
 /* GPIO channel 14 config */
 #define GPIO_14_PORT        GPIOC                   /* CC3000 VBAT_SW_EN */
 #define GPIO_14_PIN         13
-#define GPIO_14_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN)
+#define GPIO_14_CLK         2
 #define GPIO_14_EXTI_CFG()  (SYSCFG->EXTICR[3] |= SYSCFG_EXTICR4_EXTI13_PC)
 #define GPIO_14_IRQ         EXTI15_10_IRQn
 /* GPIO channel 15 config */
 #define GPIO_15_PORT        GPIOD                   /* Micro SD Sockel CS */
 #define GPIO_15_PIN         2
-#define GPIO_15_CLKEN()     (RCC->AHB1ENR |= RCC_AHB1ENR_GPIODEN)
+#define GPIO_15_CLK         3
 #define GPIO_15_EXTI_CFG()  (SYSCFG->EXTICR[0] |= SYSCFG_EXTICR1_EXTI2_PD)
 #define GPIO_15_IRQ         EXTI2_IRQn
 /** @} */