tests: drivers: spi: loopback: Add test for pico-spi-pio driver with DMA.

With the addition of a new overlay file that specifies DMA channels.

Signed-off-by: Terry Geng <[email protected]>

Author: TerryGeng

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

@@ -0,0 +1,14 @@
+#include <zephyr/dt-bindings/dma/rpi-pico-dma-rp2040.h>
+
+/* This file overrides pio0_spi0 configured in ./rpi_pico_pio.overlay
+ * and enables DMA.
+ */
+
+&dma {
+	status = "okay";
+};
+
+&pio0_spi0 {
+	dmas = <&dma 0 0 0>, <&dma 1 0 0>;
+	dma-names = "tx", "rx";
+};

tests/drivers/spi/spi_loopback/testcase.yaml

@@ -192,6 +192,14 @@ tests:
       - DTC_OVERLAY_FILE="boards/rpi_pico_pio.overlay"
       - EXTRA_CONF_FILE="overlay-rpi-pico-pio.conf"
     platform_allow: rpi_pico
+  drivers.spi.pio_spi_dma.loopback:
+    extra_args:
+      - DTC_OVERLAY_FILE="boards/rpi_pico_pio.overlay"
+      - EXTRA_DTC_OVERLAY_FILE="boards/rpi_pico_pio_dma.overlay"
+      - EXTRA_CONF_FILE="overlay-rpi-pico-pio.conf"
+    extra_configs:
+      - CONFIG_SPI_RPI_PICO_PIO_DMA=y
+    platform_allow: rpi_pico
   drivers.spi.flexio_spi.loopback:
     extra_args:
       - platform:mimxrt1170_evk/mimxrt1176/cm7:DTC_OVERLAY_FILE="boards/mimxrt1170_evk_mimxrt1176_cm7_flexio_spi.overlay"