drivers: spi: gd32: Add support DMA transfer

Add supporting DMA-based transfer for GD32 SPI.

Signed-off-by: TOKITA Hiroshi <[email protected]>

Author: soburi

drivers/spi/Kconfig.gd32

@@ -13,7 +13,16 @@ if SPI_GD32
 config SPI_GD32_INTERRUPT
 	bool "GD32 MCU SPI Interrupt Support"
 	default y if SPI_ASYNC
+	default y if SPI_GD32_DMA
 	help
 	  Enable the interrupt driven mode for SPI instances
 
+config SPI_GD32_DMA
+	bool "GD32 MCU SPI DMA Support"
+	select DMA
+	select SPI_GD32_INTERRUPT
+	help
+	  Use the DMA for SPI transfer
+	  that enable dma channels in their device tree node.
+
 endif # SPI_GD32