[PATCH v4 5/5] drm: bridge: add support for Cadence MHDP DPI/DP bridge

Heiko Stuebner
2018-09-21T08:41:59Z

Hi Damian,

Am Donnerstag, 20. September 2018, 16:54:40 CEST schrieb Damian Kos:
> From: Quentin Schulz <quentin.schulz@free-electrons.com>
>
> This adds basic support for Cadence MHDP DPI to DP bridge.
>
> Basically, it takes a DPI stream as input and output it encoded in DP
> format. It's missing proper HPD, HDCP and currently supports only
> SST mode.
>
> Changes made in the low level driver (cdn-dp-reg.*):
> - moved it to from drivers/gpu/drm/rockchip to
> drivers/gpu/drm/bridge/cdns-mhdp-common.*
> - functions for sending/receiving commands are now public
> - added functions for reading registers and link training
> adjustment
>
> Changes made in RK's driver (cdn-dp-core.*):
> - Moved audio_info and audio_pdev fields from cdn_dp_device to
> cdns_mhdp_device structure.
>
> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
> Signed-off-by: Damian Kos <dkos@cadence.com>

[...]

> diff --git a/drivers/gpu/drm/rockchip/Kconfig b/drivers/gpu/drm/rockchip/Kconfig
> index 0ccc76217ee4..129b0529f3e1 100644
> --- a/drivers/gpu/drm/rockchip/Kconfig
> +++ b/drivers/gpu/drm/rockchip/Kconfig
> @@ -27,7 +27,9 @@ config ROCKCHIP_ANALOGIX_DP
>
> config ROCKCHIP_CDN_DP
> bool "Rockchip cdn DP"
> - depends on EXTCON=y || (EXTCON=m && DRM_ROCKCHIP=m)
> + depends on DRM_ROCKCHIP=m

Sorry, I wasn't fast enough in my reply to you mail to catch that before
your v4, but I don't think this is necessary.
Instead I do guess, the select below should do the right thing by
making EXTCON=y if DRM_ROCKCHIP=y.

Somewhat clumsily verified by making EXTCON=m in my defconfig
and seeing get changed to y upon build, which I guess comes from
a different "select" in the config.

> + select EXTCON
> + select DRM_CDNS_MHDP
> help
> This selects support for Rockchip SoC specific extensions
> for the cdn DP driver. If you want to enable Dp on
> diff --git a/drivers/gpu/drm/rockchip/Makefile b/drivers/gpu/drm/rockchip/Makefile
> index a314e2109e76..16ba61ffca39 100644
> --- a/drivers/gpu/drm/rockchip/Makefile
> +++ b/drivers/gpu/drm/rockchip/Makefile
> @@ -3,13 +3,15 @@
> # Makefile for the drm device driver. This driver provides support for the
> # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
>
> +ccflags-y += -I$(src)/../bridge

hmm, instead of adding an include path, the shared header should probably
just live in /include/drm/bridge/... in the kernel source?

Heiko