boards: shields: Add nrf21540_ek shield

This commit provides the nRF21540 evaluation kit shield.

Signed-off-by: Kamil Gawor <[email protected]>

Author: Kamil Gawor

boards/shields/nrf21540_ek/Kconfig.shield

@@ -0,0 +1,8 @@
+#
+# Copyright (c) 2021 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+config SHIELD_NRF21540_EK
+	def_bool $(shields_list_contains,nrf21540_ek)

boards/shields/nrf21540_ek/nrf21540_ek.overlay

@@ -0,0 +1,29 @@
+/* Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/ {
+	nrf_radio_fem: nrf21540_fem {
+		compatible = "nordic,nrf21540-fem";
+		tx-en-gpios = <&arduino_header 11 GPIO_ACTIVE_HIGH>;   /* D5 */
+		rx-en-gpios = <&arduino_header 9 GPIO_ACTIVE_HIGH>;    /* D3 */
+		pdn-gpios = <&arduino_header 15 GPIO_ACTIVE_HIGH>;     /* D9 */
+		ant-sel-gpios = <&arduino_header 10 GPIO_ACTIVE_HIGH>; /* D4 */
+		mode-gpios = <&arduino_header 8 GPIO_ACTIVE_HIGH>;     /* D2 */
+		spi-if = <&nrf_radio_fem_spi>;
+	};
+};
+
+fem_spi: &arduino_spi {
+	status = "okay";
+	cs-gpios = <&arduino_header 16 0>; /* D10 */
+
+	nrf_radio_fem_spi: nrf21540_fem_spi@0 {
+		compatible = "nordic,nrf21540-fem-spi";
+		status = "okay";
+		reg = <0>;
+		label = "FEM_SPI_IF";
+		spi-max-frequency = <8000000>;
+	};
+};