spi: microchip: pci1xxxx: Add driver for SPI controller of PCI1XXXX PCIe switch

Microchip pci1xxxx is a PCIe switch with a multi-function endpoint on one of its
downstream ports. SPI is one of the functions in the multi-function endpoint. This
function has 2 SPI masters, operates at a maximum frequency of 30 MHz and supports
7 client devices per master. This patch adds complete functionality to the SPI
function except for suspend and resume.
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Link: https://lore.kernel.org/r/20221006050514.115564-2-tharunkumar.pasumarthi@microchip.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -710,6 +710,15 @@ config SPI_ORION
 	  This enables using the SPI master controller on the Orion
 	  and MVEBU chips.
 
+config SPI_PCI1XXXX
+	tristate "PCI1XXXX SPI Bus support"
+	depends on PCI
+	help
+	  Say "yes" to Enable the SPI Bus support for the PCI1xxxx card
+	  This is a PCI to SPI Bus driver
+	  This driver can be built as module. If so, the module will be
+	  called as spi-pci1xxxx.
+
 config SPI_PIC32
 	tristate "Microchip PIC32 series SPI"
 	depends on MACH_PIC32 || COMPILE_TEST

drivers/spi/Makefile

@@ -94,6 +94,7 @@ obj-$(CONFIG_SPI_OMAP_100K)		+= spi-omap-100k.o
 obj-$(CONFIG_SPI_OMAP24XX)		+= spi-omap2-mcspi.o
 obj-$(CONFIG_SPI_TI_QSPI)		+= spi-ti-qspi.o
 obj-$(CONFIG_SPI_ORION)			+= spi-orion.o
+obj-$(CONFIG_SPI_PCI1XXXX)		+= spi-pci1xxxx.o
 obj-$(CONFIG_SPI_PIC32)			+= spi-pic32.o
 obj-$(CONFIG_SPI_PIC32_SQI)		+= spi-pic32-sqi.o
 obj-$(CONFIG_SPI_PL022)			+= spi-pl022.o