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

Damian Kos
2018-09-24T11:40:03Z

Hi Heiko,

> 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.
>

I've changed it to:

config ROCKCHIP_CDN_DP
bool "Rockchip cdn DP"
depends on DRM_ROCKCHIP
select EXTCON if DRM_ROCKCHIP=y
select DRM_CDNS_MHDP
help...

and it seems that there are no issues. At least for me.

Please let me know if that's OK.

>
> > + 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?
>

I'll move the common header to include/drm/bridge/ in v5.

>
> Heiko

--
Damian