xtensa/esp32s2: Add SPI slave support

arch/xtensa/src/esp32s2/Kconfig

@@ -512,22 +512,44 @@ config ESP32S2_SPI_UDCS
 	---help---
 		Use user-defined CS.
 
+config ESP32S2_SPI2_SLAVE
+	bool "SPI2 Slave mode"
+	default n
+	depends on SPI_SLAVE && ESP32S2_SPI2
+	select ESP32S2_GPIO_IRQ
+	---help---
+		Configure SPI2 to operate in Slave mode.
+
 config ESP32S2_SPI2_DMA
 	bool "SPI2 use DMA"
 	default y
 	depends on ESP32S2_SPI2
 
+config ESP32S2_SPI3_SLAVE
+	bool "SPI3 Slave mode"
+	default n
+	depends on SPI_SLAVE && ESP32S2_SPI3
+	select ESP32S2_GPIO_IRQ
+	---help---
+		Configure SPI3 to operate in Slave mode.
+
 config ESP32S2_SPI3_DMA
 	bool "SPI3 use DMA"
 	default y
 	depends on ESP32S2_SPI3
 
-config SPI_DMADESC_NUM
-	int "SPI DMA maximum number of descriptors"
-	default 2
+config ESP32S2_SPI_DMA_BUFSIZE
+	int "SPI Master GDMA buffer size"
+	default 2048
+	depends on ESP32S2_SPI2_DMA || ESP32S2_SPI3_DMA
 	---help---
-		Configure the maximum number of out-link/in-link descriptors to
-		be chained for a SPI DMA transfer.
+		This is used to calculate and allocate DMA description buffer,
+		not really allocate TX/RX buffer.
+
+config ESP32S2_SPI_SLAVE_BUFSIZE
+	int "SPI Slave buffer size"
+	default 2048
+	depends on SPI_SLAVE
 
 config ESP32S2_SPI_DMATHRESHOLD
 	int "SPI DMA threshold"
@@ -559,6 +581,17 @@ config ESP32S2_SPI2_MISOPIN
 	default 13
 	range 0 48
 
+config ESP32S2_SPI2_IO2PIN
+	int "SPI2 IO2 Pin"
+	default 14
+	range 0 48
+	depends on ESP32S2_SPI_IO_QIO
+
+config ESP32S2_SPI2_IO3PIN
+	int "SPI2 IO3 Pin"
+	default 9
+	range 0 48
+	depends on ESP32S2_SPI_IO_QIO
 endif # ESP32S2_SPI2
 
 if ESP32S2_SPI3

arch/xtensa/src/esp32s2/Make.defs

@@ -69,6 +69,9 @@ endif
 
 ifeq ($(CONFIG_ESP32S2_SPI),y)
 CHIP_CSRCS += esp32s2_spi.c
+ifeq ($(CONFIG_SPI_SLAVE),y)
+CHIP_CSRCS += esp32s2_spi_slave.c
+endif
 endif
 
 #ifeq ($(CONFIG_ESP32S2_SPIFLASH),y)

arch/xtensa/src/esp32s2/esp32s2_spi.c

@@ -76,7 +76,11 @@
 
 /* SPI DMA RX/TX number of descriptors */
 
-#define SPI_DMA_DESC_NUM    (CONFIG_SPI_DMADESC_NUM)
+#  if (CONFIG_ESP32S2_SPI_DMA_BUFSIZE % ESP32S2_DMA_BUFLEN_MAX) > 0
+#    define SPI_DMA_DESC_NUM (CONFIG_ESP32S2_SPI_DMA_BUFSIZE / ESP32S2_DMA_BUFLEN_MAX + 1)
+#  else
+#    define SPI_DMA_DESC_NUM (CONFIG_ESP32S2_SPI_DMA_BUFSIZE / ESP32S2_DMA_BUFLEN_MAX)
+#  endif
 
 /* SPI DMA reset before exchange */
 

arch/xtensa/src/esp32s2/esp32s2_spi.h

@@ -46,6 +46,10 @@ extern "C"
 
 #include <nuttx/spi/spi.h>
 
+#ifdef CONFIG_SPI_SLAVE
+#  include <nuttx/spi/slave.h>
+#endif
+
 #ifdef CONFIG_ESP32S2_SPI2
 #  define ESP32S2_SPI2 2
 #endif
@@ -139,6 +143,39 @@ int esp32s2_spi3_cmddata(struct spi_dev_s *dev,
 
 int esp32s2_spibus_uninitialize(struct spi_dev_s *dev);
 
+/****************************************************************************
+ * Name: esp32s2_spislave_ctrlr_initialize
+ *
+ * Description:
+ *   Initialize the selected SPI Slave bus.
+ *
+ * Input Parameters:
+ *   port - Port number (for hardware that has multiple SPI Slave interfaces)
+ *
+ * Returned Value:
+ *   Valid SPI Slave controller structure reference on success;
+ *   NULL on failure.
+ *
+ ****************************************************************************/
+
+struct spi_slave_ctrlr_s *esp32s2_spislave_ctrlr_initialize(int port);
+
+/****************************************************************************
+ * Name: esp32s2_spislave_ctrlr_uninitialize
+ *
+ * Description:
+ *   Uninitialize an SPI Slave bus.
+ *
+ * Input Parameters:
+ *   ctrlr - SPI Slave controller interface instance
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success. Otherwise -1 (ERROR).
+ *
+ ****************************************************************************/
+
+int esp32s2_spislave_ctrlr_uninitialize(struct spi_slave_ctrlr_s *ctrlr);
+
 #endif /* CONFIG_ESP32S2_SPI */
 
 #ifdef __cplusplus