boards/nrf52840dongle: add I2C pin configuration

boards/nrf52840dongle/Kconfig

@@ -12,6 +12,7 @@ config BOARD_NRF52840DONGLE
     default y
     select BOARD_COMMON_NRF52
     select CPU_MODEL_NRF52840XXAA
+    select HAS_PERIPH_I2C
     select HAS_PERIPH_PWM
     select HAS_PERIPH_UART
     select HAS_PERIPH_SPI

boards/nrf52840dongle/Makefile.features

@@ -1,6 +1,7 @@
 CPU_MODEL = nrf52840xxaa
 
 # Put defined MCU peripherals here (in alphabetical order)
+FEATURES_PROVIDED += periph_i2c
 FEATURES_PROVIDED += periph_pwm
 FEATURES_PROVIDED += periph_uart
 FEATURES_PROVIDED += periph_usbdev

boards/nrf52840dongle/include/periph_conf.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2019 Christian Amsüss <chrysn@fsfe.org>
+ *               2021 Freie Universität Berlin
  *
  * This file is subject to the terms and conditions of the GNU Lesser
  * General Public License v2.1. See the file LICENSE in the top level
@@ -14,6 +15,7 @@
  * @brief       Peripheral configuration for the nRF52840-Dongle
  *
  * @author      Christian Amsüss <chrysn@fsfe.org>
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  *
  */
 
@@ -95,6 +97,21 @@ static const spi_conf_t spi_config[] = {
 #define SPI_NUMOF           ARRAY_SIZE(spi_config)
 /** @} */
 
+/**
+ * @name    I2C configuration
+ * @{
+ */
+static const i2c_conf_t i2c_config[] = {
+    {
+        .dev = NRF_TWIM1,
+        .scl = GPIO_PIN(0, 29),
+        .sda = GPIO_PIN(0, 31),
+        .speed = I2C_SPEED_NORMAL
+    }
+};
+#define I2C_NUMOF           ARRAY_SIZE(i2c_config)
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif