vfio/platform: Cleanup Kconfig

Like vfio-pci, there's also a base module here where vfio-amba depends on
vfio-platform, when really it only needs vfio-platform-base.  Create a
sub-menu for platform drivers and a nested menu for reset drivers.  Cleanup
Makefile to make use of new CONFIG_VFIO_PLATFORM_BASE for building the
shared modules and traversing reset modules.
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20230614193948.477036-3-alex.williamson@redhat.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/Makefile

@@ -11,6 +11,6 @@ vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_PCI_CORE) += pci/
-obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += platform/
 obj-$(CONFIG_VFIO_MDEV) += mdev/
 obj-$(CONFIG_VFIO_FSL_MC) += fsl-mc/

drivers/vfio/platform/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
-config VFIO_PLATFORM
-	tristate "VFIO support for platform devices"
+menu "VFIO support for platform devices"
 	depends on ARM || ARM64 || COMPILE_TEST
+
+config VFIO_PLATFORM_BASE
+	tristate
 	select VFIO_VIRQFD
+
+config VFIO_PLATFORM
+	tristate "Generic VFIO support for any platform device"
+	select VFIO_PLATFORM_BASE
 	help
 	  Support for platform devices with VFIO. This is required to make
 	  use of platform devices present on the system using the VFIO
@@ -10,10 +16,10 @@ config VFIO_PLATFORM
 
 	  If you don't know what to do here, say N.
 
-if VFIO_PLATFORM
 config VFIO_AMBA
 	tristate "VFIO support for AMBA devices"
 	depends on ARM_AMBA || COMPILE_TEST
+	select VFIO_PLATFORM_BASE
 	help
 	  Support for ARM AMBA devices with VFIO. This is required to make
 	  use of ARM AMBA devices present on the system using the VFIO
@@ -21,5 +27,9 @@ config VFIO_AMBA
 
 	  If you don't know what to do here, say N.
 
+menu "VFIO platform reset drivers"
+	depends on VFIO_PLATFORM_BASE
+
 source "drivers/vfio/platform/reset/Kconfig"
-endif
+endmenu
+endmenu

drivers/vfio/platform/Makefile

 # SPDX-License-Identifier: GPL-2.0
 vfio-platform-base-y := vfio_platform_common.o vfio_platform_irq.o
-vfio-platform-y := vfio_platform.o
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += vfio-platform-base.o
+obj-$(CONFIG_VFIO_PLATFORM_BASE) += reset/
 
+vfio-platform-y := vfio_platform.o
 obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
-obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform-base.o
-obj-$(CONFIG_VFIO_PLATFORM) += reset/
 
 vfio-amba-y := vfio_amba.o
-
 obj-$(CONFIG_VFIO_AMBA) += vfio-amba.o
-obj-$(CONFIG_VFIO_AMBA) += vfio-platform-base.o
-obj-$(CONFIG_VFIO_AMBA) += reset/

drivers/vfio/platform/reset/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
+if VFIO_PLATFORM
 config VFIO_PLATFORM_CALXEDAXGMAC_RESET
 	tristate "VFIO support for calxeda xgmac reset"
 	help
@@ -21,3 +22,4 @@ config VFIO_PLATFORM_BCMFLEXRM_RESET
 	  Enables the VFIO platform driver to handle reset for Broadcom FlexRM
 
 	  If you don't know what to do here, say N.
+endif