[nrf fromtree] tests: modem: backends: uart: boards: add hw-flow-control

Update the board overlays to support hardware flow control for
testing.

Signed-off-by: Bjarki Arge Andreasen <[email protected]>
(cherry picked from commit 525d3d6)

Author: bjarki-andreasen

tests/subsys/modem/backends/uart/boards/b_u585i_iot02a.conf

@@ -0,0 +1,2 @@
+CONFIG_GPIO=y
+CONFIG_GPIO_HOGS=y

tests/subsys/modem/backends/uart/boards/b_u585i_iot02a.overlay

@@ -1,11 +1,31 @@
 /* SPDX-License-Identifier: Apache-2.0 */
 
 /*
- * The Arduino D0 and D1 must be connected to each other to loopback RX/TX.
+ * The following bridges must be applied:
+ *
+ *   CN2 pin 2 <-> CN2 pin 3
+ *   CN2 pin 1 <-> CN2 pin 4
+ *
  */
 
+&gpioh {
+	status = "okay";
+
+	stmod_alternate_uart {
+		gpio-hog;
+		gpios = <15 GPIO_ACTIVE_HIGH>;
+		output-high;
+	};
+};
+
 dut: &usart3 {
+	pinctrl-0 = <&usart3_tx_pd8
+		     &usart3_rx_pd9
+		     &usart3_rts_pd12
+		     &usart3_cts_pd11>;
+	pinctrl-names = "default";
 	dmas = <&gpdma1 0 29 STM32_DMA_PERIPH_TX
 		&gpdma1 1 28 STM32_DMA_PERIPH_RX>;
 	dma-names = "tx", "rx";
+	hw-flow-control;
 };

tests/subsys/modem/backends/uart/boards/nrf5340dk_nrf5340_cpuapp.overlay

@@ -2,20 +2,25 @@
 
 /*
  * Pins P0.4 and P0.5 must be connected to each other to loopback RX/TX.
+ * Pins P0.6 and P0.7 must be connected to each other to loopback RTC/CTS.
  */
 
 &pinctrl {
 	uart1_default_alt: uart1_default_alt {
 		group1 {
 			psels = <NRF_PSEL(UART_TX, 0, 4)>,
-				<NRF_PSEL(UART_RX, 0, 5)>;
+				<NRF_PSEL(UART_RX, 0, 5)>,
+				<NRF_PSEL(UART_RTS, 0, 6)>,
+				<NRF_PSEL(UART_CTS, 0, 7)>;
 		};
 	};
 
 	uart1_sleep_alt: uart1_sleep_alt {
 		group1 {
 			psels = <NRF_PSEL(UART_TX, 0, 4)>,
-				<NRF_PSEL(UART_RX, 0, 5)>;
+				<NRF_PSEL(UART_RX, 0, 5)>,
+				<NRF_PSEL(UART_RTS, 0, 6)>,
+				<NRF_PSEL(UART_CTS, 0, 7)>;
 			low-power-enable;
 		};
 	};
@@ -24,6 +29,7 @@
 dut: &uart1 {
 	compatible = "nordic,nrf-uarte";
 	current-speed = <115200>;
+	hw-flow-control;
 	status = "okay";
 	pinctrl-0 = <&uart1_default_alt>;
 	pinctrl-1 = <&uart1_sleep_alt>;