drm: Add RP1 DPI driver

Add support for the RP1 DPI hardware.

Signed-off-by: Nick Hollinghurst <[email protected]>

drm/rp1: depends on, instead of select, MFD_RP1

According to kconfig-language.txt [1], select should be used only for
"non-visible symbols ... and for symbols with no dependencies". Since
MFD_RP1 both is visible and has a dependency, "select" should not be
used and "depends on" should be used instead.

In particular, this fixes the build of this kernel tree on NixOS, where
its kernel config system will try to answer 'M' to as many config as
possible.

[1] https://www.kernel.org/doc/html/latest/kbuild/kconfig-language.html

Signed-off-by: Ratchanan Srirattanamet <[email protected]>

drm: rp1: VEC and DPI drivers: Fix bug #5901

Rework probe() to use devm_drm_dev_alloc(), embedding the DRM
device in the DPI or VEC device as now seems to be recommended.

Change order of resource allocation and driver initialization.
This prevents it trying to write to an unmapped register during
clean-up, which previously could crash.

Signed-off-by: Nick Hollinghurst <[email protected]>

drivers/gpu/drm/rp1/rp1-dpi/Kconfig

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config DRM_RP1_DPI
+	tristate "DRM Support for RP1 DPI"
+	depends on DRM && MFD_RP1
+	select DRM_GEM_DMA_HELPER
+	select DRM_KMS_HELPER
+	select DRM_VRAM_HELPER
+	select DRM_TTM
+	select DRM_TTM_HELPER
+	help
+	  Choose this option to enable Video Out on RP1

drivers/gpu/drm/rp1/rp1-dpi/Makefile

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+drm-rp1-dpi-y := rp1_dpi.o rp1_dpi_hw.o rp1_dpi_cfg.o
+
+obj-$(CONFIG_DRM_RP1_DPI) += drm-rp1-dpi.o