esp32[c3|c6|h2]: Add SPI bitbang support

Documentation/platforms/risc-v/esp32c3/boards/esp32c3-generic/index.rst

@@ -244,6 +244,10 @@ This configuration enables the support for the SPI driver.
 You can test it by connecting MOSI and MISO pins which are GPIO7 and GPIO2
 by default to each other and running the ``spi`` example::
 
+If SPI peripherals are already in use you can also use bitbang driver which is a
+software implemented SPI peripheral by enabling `CONFIG_ESPRESSIF_SPI_BITBANG`
+option.
+
     nsh> spi exch -b 2 "AB"
     Sending:	AB
     Received:	AB

Documentation/platforms/risc-v/esp32c6/boards/esp32c6-devkitc/index.rst

@@ -256,6 +256,10 @@ This configuration enables the support for the SPI driver.
 You can test it by connecting MOSI and MISO pins which are GPIO7 and GPIO2
 by default to each other and running the ``spi`` example::
 
+If SPI peripherals are already in use you can also use bitbang driver which is a
+software implemented SPI peripheral by enabling `CONFIG_ESPRESSIF_SPI_BITBANG`
+option.
+
     nsh> spi exch -b 2 "AB"
     Sending:	AB
     Received:	AB

Documentation/platforms/risc-v/esp32c6/boards/esp32c6-devkitm/index.rst

@@ -218,6 +218,10 @@ This configuration enables the support for the SPI driver.
 You can test it by connecting MOSI and MISO pins which are GPIO7 and GPIO2
 by default to each other and running the ``spi`` example::
 
+If SPI peripherals are already in use you can also use bitbang driver which is a
+software implemented SPI peripheral by enabling `CONFIG_ESPRESSIF_SPI_BITBANG`
+option.
+
     nsh> spi exch -b 2 "AB"
     Sending:	AB
     Received:	AB

Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst

@@ -217,6 +217,10 @@ This configuration enables the support for the SPI driver.
 You can test it by connecting MOSI and MISO pins which are GPIO5 and GPIO0
 by default to each other and running the ``spi`` example::
 
+If SPI peripherals are already in use you can also use bitbang driver which is a
+software implemented SPI peripheral by enabling `CONFIG_ESPRESSIF_SPI_BITBANG`
+option.
+
     nsh> spi exch -b 2 "AB"
     Sending:	AB
     Received:	AB

arch/risc-v/src/common/espressif/Kconfig

@@ -337,11 +337,26 @@ config ESPRESSIF_SPI
 	bool
 	default n
 
+config ESPRESSIF_SPI_PERIPH
+	bool
+	depends on ESPRESSIF_SPI2
+	default n
+
 config ESPRESSIF_SPI2
 	bool "SPI 2"
 	default n
 	select ESPRESSIF_SPI
 	select SPI
+	select ESPRESSIF_SPI_PERIPH
+
+config ESPRESSIF_SPI_BITBANG
+	bool "SPI Bitbang"
+	default n
+	select ESPRESSIF_SPI
+	select SPI
+	select SPI_BITBANG
+	---help---
+		Software implemented SPI peripheral with GPIOs. Suggested to use if SPI peripheral is already in use.
 
 config ESPRESSIF_SPIFLASH
 	bool "SPI Flash"
@@ -1150,6 +1165,7 @@ menu "SPI configuration"
 
 config ESPRESSIF_SPI_SWCS
 	bool "SPI software CS"
+	depends on ESPRESSIF_SPI_PERIPH
 	default n
 	---help---
 		Use SPI software CS.
@@ -1158,6 +1174,7 @@ config ESPRESSIF_SPI_UDCS
 	bool "User defined CS"
 	default n
 	depends on ESPRESSIF_SPI_SWCS
+	depends on ESPRESSIF_SPI_PERIPH
 	---help---
 		Use user-defined CS.
 
@@ -1228,10 +1245,53 @@ config ESPRESSIF_SPI2_MISOPIN
 
 endif # ESPRESSIF_SPI2
 
+if ESPRESSIF_SPI_BITBANG
+
+config ESPRESSIF_SPI_BITBANG_CSPIN
+	int "SPI Bitbang CS Pin"
+	default 0
+	range 0 21
+
+config ESPRESSIF_SPI_BITBANG_CLKPIN
+	int "SPI Bitbang CLK Pin"
+	default 1
+	range 0 21
+
+config ESPRESSIF_SPI_BITBANG_MOSIPIN
+	int "SPI Bitbang MOSI Pin"
+	default 2
+	range 0 21
+
+config ESPRESSIF_SPI_BITBANG_MISOPIN
+	int "SPI Bitbang MISO Pin"
+	default 3
+	range 0 21
+
+choice ESPRESSIF_SPI_BITBANG_MODE
+	prompt "SPI Bitbang mode"
+	default ESPRESSIF_SPI_BITBANG_MODE0
+
+config ESPRESSIF_SPI_BITBANG_MODE0
+	bool "SPI MODE0"
+
+config ESPRESSIF_SPI_BITBANG_MODE1
+	bool "SPI MODE1"
+
+config ESPRESSIF_SPI_BITBANG_MODE2
+	bool "SPI MODE2"
+
+config ESPRESSIF_SPI_BITBANG_MODE3
+	bool "SPI MODE3"
+
+endchoice # ESPRESSIF_SPI_BITBANG_MODE
+
+endif # ESPRESSIF_SPI_BITBANG
+
 config ESPRESSIF_SPI_TEST_MODE
 	bool "SPI driver loopback test mode (for testing only)"
 	default n
 	depends on SYSTEM_SPITOOL
+	depends on ESPRESSIF_SPI_PERIPH
 	---help---
 		This enables a loopback test mode that attaches the transmitter
 		to the receiver internally, being able to test the SPI

arch/risc-v/src/common/espressif/Make.defs

@@ -103,10 +103,15 @@ ifeq ($(CONFIG_ESPRESSIF_I2C),y)
 endif
 
 ifeq ($(CONFIG_ESPRESSIF_SPI),y)
-	CHIP_CSRCS += esp_spi.c
+	ifeq ($(CONFIG_ESPRESSIF_SPI_PERIPH),y)
+		CHIP_CSRCS += esp_spi.c
+	endif
 	ifeq ($(CONFIG_SPI_SLAVE),y)
 		CHIP_CSRCS += esp_spi_slave.c
 	endif
+	ifeq ($(CONFIG_ESPRESSIF_SPI_BITBANG),y)
+		CHIP_CSRCS += esp_spi_bitbang.c
+	endif
 endif
 
 ifeq ($(CONFIG_ESPRESSIF_SPIFLASH),y)

arch/risc-v/src/common/espressif/esp_spi.c

@@ -24,7 +24,7 @@
 
 #include <nuttx/config.h>
 
-#ifdef CONFIG_ESPRESSIF_SPI
+#ifdef CONFIG_ESPRESSIF_SPI_PERIPH
 
 #include <assert.h>
 #include <debug.h>
@@ -1283,4 +1283,4 @@ int esp_spibus_uninitialize(struct spi_dev_s *dev)
   return OK;
 }
 
-#endif /* CONFIG_ESPRESSIF_SPI */
+#endif /* CONFIG_ESPRESSIF_SPI_PERIPH */

arch/risc-v/src/common/espressif/esp_spi.h

@@ -42,13 +42,11 @@ extern "C"
 #define EXTERN extern
 #endif
 
-#ifdef CONFIG_ESPRESSIF_SPI
+#ifdef CONFIG_ESPRESSIF_SPI_PERIPH
 
 #include <nuttx/spi/spi.h>
 
-#ifdef CONFIG_ESPRESSIF_SPI2
-#  define ESPRESSIF_SPI2 2
-#endif
+#define ESPRESSIF_SPI2 2
 
 /****************************************************************************
  * Public Function Prototypes
@@ -159,7 +157,7 @@ struct spi_slave_ctrlr_s *esp_spislave_ctrlr_initialize(int port);
 
 int esp_spislave_ctrlr_uninitialize(struct spi_slave_ctrlr_s *ctrlr);
 
-#endif /* CONFIG_ESPRESSIF_SPI */
+#endif /* CONFIG_ESPRESSIF_SPI_PERIPH */
 
 #ifdef __cplusplus
 }