From 820a70242f443126b1dad2f94f6c89924321dcb4 Mon Sep 17 00:00:00 2001
From: cyliang tw <cyliang@nuvoton.com>
Date: Wed, 27 Mar 2024 12:09:55 +0800
Subject: [PATCH] drivers: spi: support for Nuvoton numaker m2l31x

Update m2l31x.dtsi for spi support and update spi_numaker.c
for dummy TX data.

Signed-off-by: cyliang tw <cyliang@nuvoton.com>
---
 drivers/spi/spi_numaker.c   | 10 +++++++++
 dts/arm/nuvoton/m2l31x.dtsi | 44 +++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/drivers/spi/spi_numaker.c b/drivers/spi/spi_numaker.c
index eda34014eb..104439e9a5 100644
--- a/drivers/spi/spi_numaker.c
+++ b/drivers/spi/spi_numaker.c
@@ -186,6 +186,16 @@ static int spi_numaker_txrx(const struct device *dev)
 		}
 
 		LOG_DBG("%s --> TX [0x%x] done", __func__, tx_frame);
+	} else {
+		/* Write dummy data to TX register */
+		SPI_WRITE_TX(dev_cfg->spi, 0x00U);
+		time_out_cnt = SystemCoreClock; /* 1 second time-out */
+		while (SPI_IS_BUSY(dev_cfg->spi)) {
+			if (--time_out_cnt == 0) {
+				LOG_ERR("Wait for SPI time-out");
+				return -EIO;
+			}
+		}
 	}
 
 	/* Read received data */
diff --git a/dts/arm/nuvoton/m2l31x.dtsi b/dts/arm/nuvoton/m2l31x.dtsi
index 00af64b124..51d38c3ee6 100644
--- a/dts/arm/nuvoton/m2l31x.dtsi
+++ b/dts/arm/nuvoton/m2l31x.dtsi
@@ -213,6 +213,50 @@
 			status = "disabled";
 			interrupts = <21 2>;
 		};
+
+		spi0: spi@40061000 {
+			compatible = "nuvoton,numaker-spi";
+			reg = <0x40061000 0x6c>;
+			interrupts = <23 0>;
+			resets = <&rst NUMAKER_SPI0_RST>;
+			clocks = <&pcc NUMAKER_SPI0_MODULE NUMAKER_CLK_CLKSEL2_SPI0SEL_HIRC 0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "disabled";
+		};
+
+		spi1: spi@40062000 {
+			compatible = "nuvoton,numaker-spi";
+			reg = <0x40062000 0x6c>;
+			interrupts = <51 0>;
+			resets = <&rst NUMAKER_SPI1_RST>;
+			clocks = <&pcc NUMAKER_SPI1_MODULE NUMAKER_CLK_CLKSEL2_SPI1SEL_HIRC 0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "disabled";
+		};
+
+		spi2: spi@40063000 {
+			compatible = "nuvoton,numaker-spi";
+			reg = <0x40063000 0x6c>;
+			interrupts = <52 0>;
+			resets = <&rst NUMAKER_SPI2_RST>;
+			clocks = <&pcc NUMAKER_SPI2_MODULE NUMAKER_CLK_CLKSEL3_SPI2SEL_HIRC 0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "disabled";
+		};
+
+		spi3: spi@40064000 {
+			compatible = "nuvoton,numaker-spi";
+			reg = <0x40064000 0x6c>;
+			interrupts = <62 0>;
+			resets = <&rst NUMAKER_SPI3_RST>;
+			clocks = <&pcc NUMAKER_SPI3_MODULE NUMAKER_CLK_CLKSEL3_SPI3SEL_HIRC 0>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			status = "disabled";
+		};
 	};
 };