[nrf fromlist] boards: nrf9160dk: Add DT node for I/O expander ...

... available in v0.14.0+

Upstream PR: zephyrproject-rtos/zephyr#31624

Add devicetree node representing the PCAL6408A I2C-based I/O expander
that is available in nRF9160 DK v0.14.0 or later.
Provide also .dtsi files that can be used in applications to simplify
switching to interfacing onboard LEDs and buttons through this expander
instead of SoC pins.

Signed-off-by: Andrzej Głąbek <[email protected]>

boards/arm/nrf9160dk_nrf52840/dts/nrf9160dk_buttons_on_io_expander.dtsi

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* NOTE: this feature is only available in nRF9160 DK v0.14.0 or later. */
+
+&switch1_pin_routing {
+	status = "disabled";
+};
+
+&switch2_pin_routing {
+	status = "disabled";
+};
+
+&button1_pin_routing {
+	status = "disabled";
+};
+
+&button2_pin_routing {
+	status = "disabled";
+};
+
+&io_expander_pins_routing {
+	status = "okay";
+};

boards/arm/nrf9160dk_nrf52840/dts/nrf9160dk_leds_on_io_expander.dtsi

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* NOTE: this feature is only available in nRF9160 DK v0.14.0 or later. */
+
+&led1_pin_routing {
+	status = "disabled";
+};
+
+&led2_pin_routing {
+	status = "disabled";
+};
+
+&led3_pin_routing {
+	status = "disabled";
+};
+
+&led4_pin_routing {
+	status = "disabled";
+};
+
+&io_expander_pins_routing {
+	status = "okay";
+};

boards/arm/nrf9160dk_nrf9160/Kconfig.defconfig

@@ -38,4 +38,10 @@ endif # BOARD_NRF9160DK_NRF9160NS
 config BT_WAIT_NOP
 	default BT && $(dt_nodelabel_enabled,nrf52840_reset)
 
+# Workaround for not being able to have commas in macro arguments
+DT_COMPAT_NXP_PCAL6408A := nxp,pcal6408a
+
+config I2C
+	default $(dt_compat_on_bus,$(DT_COMPAT_NXP_PCAL6408A),i2c)
+
 endif # BOARD_NRF9160DK_NRF9160 || BOARD_NRF9160DK_NRF9160NS

boards/arm/nrf9160dk_nrf9160/dts/nrf9160dk_buttons_on_io_expander.dtsi

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* NOTE: this feature is only available in nRF9160 DK v0.14.0 or later. */
+
+&pcal6408a {
+	status = "okay";
+};
+
+&button0 {
+	gpios = <&pcal6408a 2 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+};
+
+&button1 {
+	gpios = <&pcal6408a 3 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+};
+
+&button2 {
+	gpios = <&pcal6408a 0 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+};
+
+&button3 {
+	gpios = <&pcal6408a 1 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+};

boards/arm/nrf9160dk_nrf9160/dts/nrf9160dk_leds_on_io_expander.dtsi

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* NOTE: this feature is only available in nRF9160 DK v0.14.0 or later. */
+
+&pcal6408a {
+	status = "okay";
+};
+
+&led0 {
+	gpios = <&pcal6408a 4 GPIO_ACTIVE_HIGH>;
+};
+
+&led1 {
+	gpios = <&pcal6408a 5 GPIO_ACTIVE_HIGH>;
+};
+
+&led2 {
+	gpios = <&pcal6408a 6 GPIO_ACTIVE_HIGH>;
+};
+
+&led3 {
+	gpios = <&pcal6408a 7 GPIO_ACTIVE_HIGH>;
+};

boards/arm/nrf9160dk_nrf9160/nrf9160dk_nrf9160_common_0_14_0.dtsi

@@ -21,6 +21,24 @@
 	gpios = <&interface_to_nrf52840 9 GPIO_ACTIVE_LOW>;
 };
 
+&i2c2 {
+	status = "okay";
+	clock-frequency = <I2C_BITRATE_FAST>;
+	sda-pin = <30>;
+	scl-pin = <31>;
+
+	pcal6408a: pcal6408a@20 {
+		compatible = "nxp,pcal6408a";
+		status = "disabled";
+		reg = <0x20>;
+		label = "GPIO_P0";
+		gpio-controller;
+		#gpio-cells = <2>;
+		ngpios = <8>;
+		int-gpios = <&gpio0 6 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+	};
+};
+
 &spi3 {
 	status = "okay";
 	sck-pin = <13>;