tests: drivers: spi loopback in async mode with or w/o DMA

Add the overlay and config to run the spi loopback test
transfer with DMA and also in async mode with DMA
on any stm32 platform.
New target disco_l475_iot1

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

tests/drivers/spi/spi_loopback/boards/disco_l475_iot1.overlay

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2023 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&spi1 {
+	dmas = <&dma1 1 3 STM32_DMA_PERIPH_TX
+		&dma1 1 2 STM32_DMA_PERIPH_RX>;
+	dma-names = "tx", "rx";
+	slow@0 {
+		compatible = "test-spi-loopback-slow";
+		reg = <0>;
+		spi-max-frequency = <500000>;
+	};
+	fast@0 {
+		compatible = "test-spi-loopback-fast";
+		reg = <0>;
+		spi-max-frequency = <16000000>;
+	};
+};

tests/drivers/spi/spi_loopback/testcase.yaml

@@ -33,9 +33,28 @@ tests:
     integration_platforms:
       - sam_e70_xplained
   drivers.spi.stm32_spi_dma.loopback:
-    extra_args: OVERLAY_CONFIG="overlay-stm32-spi-dma.conf"
+    extra_configs:
+      - CONFIG_SPI_STM32_DMA=y
+      - CONFIG_SPI_ASYNC=n
+    filter: CONFIG_SOC_FAMILY_STM32
+    platform_allow:
+      - disco_l475_iot1
+      - nucleo_g474re
+      - nucleo_f207zg
+      - nucleo_f429zi
+      - nucleo_f746zg
+      - nucleo_wb55rg
+      - nucleo_l152re
+      - nucleo_wl55jc
+      - nucleo_h743zi
+    integration_platforms:
+      - nucleo_g474re
+  drivers.spi.stm32_spi_async_dma.loopback:
+    extra_configs:
+      - CONFIG_SPI_STM32_DMA=y
     filter: CONFIG_SOC_FAMILY_STM32
     platform_allow:
+      - disco_l475_iot1
       - nucleo_g474re
       - nucleo_f207zg
       - nucleo_f429zi