drm/display: Introduce a DRM display-helper module

Replace the DP-helper module with a display-helper module. The
support for DisplayPort becomes an internal option that drivers
have to select. Update all related Kconfig and Makefile rules.

Besides the existing code for DisplayPort, the new module will
contain helpers for other video-output standards, such as HDMI.
Drivers will have to select their required video-output helpers.

Linking all display-related code into a single module avoids the
proliferation of small kernel modules.

The module parameters drm_dp_cec_unregister_delay, dp_aux_i2c_speed_khz,
and dp_aux_i2c_transfer_size are moving from the drm_dp_helper namespace
to drm_display_helper.

v2:
	* mention module parameters in commit message (Javier)
	* distiguish between display module and DP support in Kconfig
	* update Makefile rules for DP helpers
	* move Kconfig rules into separate file under display/
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220421073108.19226-4-tzimmermann@suse.de

drivers/gpu/drm/Kconfig

@@ -36,19 +36,6 @@ config DRM_MIPI_DSI
 	bool
 	depends on DRM
 
-config DRM_DP_AUX_BUS
-	tristate
-	depends on DRM
-	depends on OF
-
-config DRM_DP_AUX_CHARDEV
-	bool "DRM DP AUX Interface"
-	depends on DRM
-	help
-	  Choose this option to enable a /dev/drm_dp_auxN node that allows to
-	  read and write values to arbitrary DPCD registers on the DP aux
-	  channel.
-
 config DRM_DEBUG_MM
 	bool "Insert extra checks and debug info into the DRM range managers"
 	default n
@@ -68,7 +55,8 @@ config DRM_DEBUG_SELFTEST
 	depends on DRM
 	depends on DEBUG_KERNEL
 	select PRIME_NUMBERS
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_LIB_RANDOM
 	select DRM_KMS_HELPER
 	select DRM_BUDDY
@@ -82,12 +70,6 @@ config DRM_DEBUG_SELFTEST
 
 	  If in doubt, say "N".
 
-config DRM_DP_HELPER
-	tristate
-	depends on DRM
-	help
-	  DRM helpers for DisplayPort.
-
 config DRM_KMS_HELPER
 	tristate
 	depends on DRM
@@ -187,16 +169,7 @@ config DRM_LOAD_EDID_FIRMWARE
 	  default case is N. Details and instructions how to build your own
 	  EDID data are given in Documentation/admin-guide/edid.rst.
 
-config DRM_DP_CEC
-	bool "Enable DisplayPort CEC-Tunneling-over-AUX HDMI support"
-	depends on DRM
-	select CEC_CORE
-	help
-	  Choose this option if you want to enable HDMI CEC support for
-	  DisplayPort/USB-C to HDMI adapters.
-
-	  Note: not all adapters support this feature, and even for those
-	  that do support this they often do not hook up the CEC pin.
+source "drivers/gpu/drm/display/Kconfig"
 
 config DRM_TTM
 	tristate
@@ -250,7 +223,8 @@ config DRM_RADEON
 	depends on DRM && PCI && MMU
 	depends on AGP || !AGP
 	select FW_LOADER
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
         select DRM_KMS_HELPER
         select DRM_TTM
 	select DRM_TTM_HELPER
@@ -271,7 +245,8 @@ config DRM_AMDGPU
 	tristate "AMD GPU"
 	depends on DRM && PCI && MMU
 	select FW_LOADER
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select DRM_SCHED
 	select DRM_TTM

drivers/gpu/drm/bridge/Kconfig

@@ -78,8 +78,9 @@ config DRM_DISPLAY_CONNECTOR
 config DRM_ITE_IT6505
         tristate "ITE IT6505 DisplayPort bridge"
         depends on OF
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
         select DRM_DP_AUX_BUS
-	select DRM_DP_HELPER
         select DRM_KMS_HELPER
         select EXTCON
         help
@@ -206,8 +207,9 @@ config DRM_PARADE_PS8622
 config DRM_PARADE_PS8640
 	tristate "Parade PS8640 MIPI DSI to eDP Converter"
 	depends on OF
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_DP_AUX_BUS
-	select DRM_DP_HELPER
 	select DRM_KMS_HELPER
 	select DRM_MIPI_DSI
 	select DRM_PANEL
@@ -278,7 +280,8 @@ config DRM_TOSHIBA_TC358764
 config DRM_TOSHIBA_TC358767
 	tristate "Toshiba TC358767 eDP bridge"
 	depends on OF
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	select DRM_MIPI_DSI
@@ -299,7 +302,8 @@ config DRM_TOSHIBA_TC358768
 config DRM_TOSHIBA_TC358775
 	tristate "Toshiba TC358775 DSI/LVDS bridge"
 	depends on OF
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	select DRM_PANEL
@@ -327,7 +331,8 @@ config DRM_TI_SN65DSI83
 config DRM_TI_SN65DSI86
 	tristate "TI SN65DSI86 DSI to eDP bridge"
 	depends on OF
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	select DRM_PANEL

drivers/gpu/drm/bridge/analogix/Kconfig

@@ -3,7 +3,8 @@ config DRM_ANALOGIX_ANX6345
 	tristate "Analogix ANX6345 bridge"
 	depends on OF
 	select DRM_ANALOGIX_DP
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	help
@@ -15,7 +16,8 @@ config DRM_ANALOGIX_ANX6345
 config DRM_ANALOGIX_ANX78XX
 	tristate "Analogix ANX78XX bridge"
 	select DRM_ANALOGIX_DP
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	help
@@ -32,8 +34,9 @@ config DRM_ANALOGIX_ANX7625
 	tristate "Analogix Anx7625 MIPI to DP interface support"
 	depends on DRM
 	depends on OF
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_DP_AUX_BUS
-	select DRM_DP_HELPER
 	select DRM_MIPI_DSI
 	help
 	  ANX7625 is an ultra-low power 4K mobile HD transmitter

drivers/gpu/drm/bridge/cadence/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 config DRM_CDNS_MHDP8546
 	tristate "Cadence DPI/DP bridge"
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select DRM_PANEL_BRIDGE
 	depends on OF

drivers/gpu/drm/display/Kconfig

+# SPDX-License-Identifier: MIT
+
+config DRM_DP_AUX_BUS
+	tristate
+	depends on DRM
+	depends on OF
+
+config DRM_DISPLAY_HELPER
+	tristate
+	depends on DRM
+	help
+	  DRM helpers for display adapters.
+
+config DRM_DISPLAY_DP_HELPER
+	bool
+	depends on DRM_DISPLAY_HELPER
+	help
+	  DRM display helpers for DisplayPort.
+
+config DRM_DP_AUX_CHARDEV
+	bool "DRM DP AUX Interface"
+	depends on DRM
+	help
+	  Choose this option to enable a /dev/drm_dp_auxN node that allows to
+	  read and write values to arbitrary DPCD registers on the DP aux
+	  channel.
+
+config DRM_DP_CEC
+	bool "Enable DisplayPort CEC-Tunneling-over-AUX HDMI support"
+	depends on DRM
+	select CEC_CORE
+	help
+	  Choose this option if you want to enable HDMI CEC support for
+	  DisplayPort/USB-C to HDMI adapters.
+
+	  Note: not all adapters support this feature, and even for those
+	  that do support this they often do not hook up the CEC pin.

drivers/gpu/drm/display/Makefile

@@ -2,8 +2,11 @@
 
 obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o
 
-drm_dp_helper-y := drm_dp.o drm_dp_dual_mode_helper.o drm_dp_helper_mod.o drm_dp_mst_topology.o
-drm_dp_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
-drm_dp_helper-$(CONFIG_DRM_DP_CEC) += drm_dp_cec.o
+drm_display_helper-y := drm_display_helper_mod.o
+drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_HELPER) += drm_dp_dual_mode_helper.o \
+						      drm_dp_helper.o \
+						      drm_dp_mst_topology.o
+drm_display_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
+drm_display_helper-$(CONFIG_DRM_DP_CEC) += drm_dp_cec.o
 
-obj-$(CONFIG_DRM_DP_HELPER) += drm_dp_helper.o
+obj-$(CONFIG_DRM_DISPLAY_HELPER) += drm_display_helper.o

drivers/gpu/drm/display/drm_dp_helper_mod.c → drivers/gpu/drm/display/drm_display_helper_mod.c

@@ -4,19 +4,19 @@
 
 #include "drm_dp_helper_internal.h"
 
-MODULE_DESCRIPTION("DRM DisplayPort helper");
+MODULE_DESCRIPTION("DRM display adapter helper");
 MODULE_LICENSE("GPL and additional rights");
 
-static int __init drm_dp_helper_module_init(void)
+static int __init drm_display_helper_module_init(void)
 {
 	return drm_dp_aux_dev_init();
 }
 
-static void __exit drm_dp_helper_module_exit(void)
+static void __exit drm_display_helper_module_exit(void)
 {
 	/* Call exit functions from specific dp helpers here */
 	drm_dp_aux_dev_exit();
 }
 
-module_init(drm_dp_helper_module_init);
-module_exit(drm_dp_helper_module_exit);
+module_init(drm_display_helper_module_init);
+module_exit(drm_display_helper_module_exit);

drivers/gpu/drm/exynos/Kconfig

@@ -4,6 +4,7 @@ config DRM_EXYNOS
 	depends on OF && DRM && COMMON_CLK
 	depends on ARCH_S3C64XX || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_MULTIPLATFORM || COMPILE_TEST
 	depends on MMU
+	select DRM_DISPLAY_HELPER if DRM_EXYNOS_DP
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
 	select SND_SOC_HDMI_CODEC if SND_SOC
@@ -66,7 +67,7 @@ config DRM_EXYNOS_DP
 	bool "Exynos specific extensions for Analogix DP driver"
 	depends on DRM_EXYNOS_FIMD || DRM_EXYNOS7_DECON
 	select DRM_ANALOGIX_DP
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
 	default DRM_EXYNOS
 	select DRM_PANEL
 	help

drivers/gpu/drm/i915/Kconfig

@@ -10,7 +10,8 @@ config DRM_I915
 	# the shmem_readpage() which depends upon tmpfs
 	select SHMEM
 	select TMPFS
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select DRM_PANEL
 	select DRM_MIPI_DSI

drivers/gpu/drm/msm/Kconfig

@@ -12,7 +12,8 @@ config DRM_MSM
 	select IOMMU_IO_PGTABLE
 	select QCOM_MDT_LOADER if ARCH_QCOM
 	select REGULATOR
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select DRM_PANEL
 	select DRM_BRIDGE

drivers/gpu/drm/nouveau/Kconfig

@@ -4,7 +4,8 @@ config DRM_NOUVEAU
 	depends on DRM && PCI && MMU
 	select IOMMU_API
 	select FW_LOADER
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_KMS_HELPER
 	select DRM_TTM
 	select DRM_TTM_HELPER

drivers/gpu/drm/panel/Kconfig

@@ -105,8 +105,9 @@ config DRM_PANEL_EDP
 	depends on BACKLIGHT_CLASS_DEVICE
 	depends on PM
 	select VIDEOMODE_HELPERS
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_DP_AUX_BUS
-	select DRM_DP_HELPER
 	select DRM_KMS_HELPER
 	help
 	  DRM panel driver for dumb eDP panels that need at most a regulator and

drivers/gpu/drm/rockchip/Kconfig

@@ -2,13 +2,12 @@
 config DRM_ROCKCHIP
 	tristate "DRM Support for Rockchip"
 	depends on DRM && ROCKCHIP_IOMMU
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_HELPER if ROCKCHIP_ANALOGIX_DP
 	select DRM_GEM_CMA_HELPER
 	select DRM_KMS_HELPER
 	select DRM_PANEL
 	select VIDEOMODE_HELPERS
 	select DRM_ANALOGIX_DP if ROCKCHIP_ANALOGIX_DP
-	select DRM_DP_HELPER if ROCKCHIP_ANALOGIX_DP
 	select DRM_DW_HDMI if ROCKCHIP_DW_HDMI
 	select DRM_DW_MIPI_DSI if ROCKCHIP_DW_MIPI_DSI
 	select GENERIC_PHY if ROCKCHIP_DW_MIPI_DSI
@@ -25,6 +24,7 @@ if DRM_ROCKCHIP
 
 config ROCKCHIP_ANALOGIX_DP
 	bool "Rockchip specific extensions for Analogix DP driver"
+	select DRM_DISPLAY_DP_HELPER
 	help
 	  This selects support for Rockchip SoC specific extensions
 	  for the Analogix Core DP driver. If you want to enable DP

drivers/gpu/drm/tegra/Kconfig

@@ -5,8 +5,9 @@ config DRM_TEGRA
 	depends on COMMON_CLK
 	depends on DRM
 	depends on OF
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_DP_AUX_BUS
-	select DRM_DP_HELPER
 	select DRM_KMS_HELPER
 	select DRM_MIPI_DSI
 	select DRM_PANEL

drivers/gpu/drm/xlnx/Kconfig

@@ -6,7 +6,8 @@ config DRM_ZYNQMP_DPSUB
 	depends on PHY_XILINX_ZYNQMP
 	depends on XILINX_ZYNQMP_DPDMA
 	select DMA_ENGINE
-	select DRM_DP_HELPER
+	select DRM_DISPLAY_DP_HELPER
+	select DRM_DISPLAY_HELPER
 	select DRM_GEM_CMA_HELPER
 	select DRM_KMS_HELPER
 	select GENERIC_PHY