spi: Add support for Renesas CSI

The RZ/V2M SoC comes with the Clocked Serial Interface (CSI)
IP, which is a master/slave SPI controller.

This commit adds a driver to support CSI master mode.
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Link: https://lore.kernel.org/r/Message-Id: <20230622113341.657842-4-fabrizio.castro.jz@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -825,6 +825,12 @@ config SPI_RSPI
 	help
 	  SPI driver for Renesas RSPI and QSPI blocks.
 
+config SPI_RZV2M_CSI
+	tristate "Renesas RZV2M CSI controller"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	help
+	  SPI driver for Renesas RZ/V2M Clocked Serial Interface (CSI)
+
 config SPI_QCOM_QSPI
 	tristate "QTI QSPI controller"
 	depends on ARCH_QCOM || COMPILE_TEST

drivers/spi/Makefile

@@ -113,6 +113,7 @@ obj-$(CONFIG_SPI_RB4XX)			+= spi-rb4xx.o
 obj-$(CONFIG_MACH_REALTEK_RTL)		+= spi-realtek-rtl.o
 obj-$(CONFIG_SPI_RPCIF)			+= spi-rpc-if.o
 obj-$(CONFIG_SPI_RSPI)			+= spi-rspi.o
+obj-$(CONFIG_SPI_RZV2M_CSI)		+= spi-rzv2m-csi.o
 obj-$(CONFIG_SPI_S3C64XX)		+= spi-s3c64xx.o
 obj-$(CONFIG_SPI_SC18IS602)		+= spi-sc18is602.o
 obj-$(CONFIG_SPI_SH)			+= spi-sh.o