dongle: set regout0 to provide 3.3V from USB (#361)

boards/ugl/uhk-80/CMakeLists.txt

@@ -0,0 +1,4 @@
+zephyr_library()
+if(CONFIG_DEVICE_ID) # don't add it to bootloader image as well
+    zephyr_library_sources(board.c)
+endif()

boards/ugl/uhk-80/board.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018 Nordic Semiconductor ASA.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/init.h>
+#include <hal/nrf_power.h>
+
+#ifdef CONFIG_BOARD_UHK_DONGLE_NRF52840
+static int board_uhk_dongle_nrf52840_init(void)
+{
+	/* if the nrf52840dongle_nrf52840 board is powered from USB
+	 * (high voltage mode), GPIO output voltage is set to 1.8 volts by
+	 * default and that is not enough to turn the green and blue LEDs on.
+	 * Increase GPIO voltage to 3.3 volts. */
+	if ((nrf_power_mainregstatus_get(NRF_POWER) ==
+	     NRF_POWER_MAINREGSTATUS_HIGH) &&
+	    ((NRF_UICR->REGOUT0 & UICR_REGOUT0_VOUT_Msk) ==
+	     (UICR_REGOUT0_VOUT_DEFAULT << UICR_REGOUT0_VOUT_Pos))) {
+
+		NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
+		while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
+			;
+		}
+
+		NRF_UICR->REGOUT0 =
+		    (NRF_UICR->REGOUT0 & ~((uint32_t)UICR_REGOUT0_VOUT_Msk)) |
+		    (UICR_REGOUT0_VOUT_3V3 << UICR_REGOUT0_VOUT_Pos);
+
+		NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
+		while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
+			;
+		}
+
+		/* a reset is required for changes to take effect */
+		NVIC_SystemReset();
+	}
+
+	return 0;
+}
+
+SYS_INIT(board_uhk_dongle_nrf52840_init, PRE_KERNEL_1,
+	 CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
+#endif