Most bridge drivers create a DRM connector to model the connector at the
output of the bridge. This model is historical and has worked pretty
well so far, but causes several issues:

- It prevents supporting more complex display pipelines where DRM
connector operations are split over multiple components. For instance a
pipeline with a bridge connected to the DDC signals to read EDID data,
and another one connected to the HPD signal to detect connection and
disconnection, will not be possible to support through this model.

- It requires every bridge driver to implement similar connector
handling code, resulting in code duplication.

- It assumes that a bridge will either be wired to a connector or to
another bridge, but doesn't support bridges that can be used in both
positions very well (although there is some ad-hoc support for this in
the analogix_dp bridge driver).

In order to solve these issues, ownership of the connector should be
moved to the display controller driver (where it can be implemented
using helpers provided by the core).

Extend the bridge API to allow disabling connector creation in bridge
drivers as a first step towards the new model. The new flags argument to
the bridge .attach() operation allows instructing the bridge driver to
skip creating a connector. Unconditionally set the new flags argument to
0 for now to keep the existing behaviour, and modify all existing bridge
drivers to return an error when connector creation is not requested as
they don't support this feature yet.

The change is based on the following semantic patch, with manual review
and edits.

@ rule1 @
identifier funcs;
identifier fn;
@@
 struct drm_bridge_funcs funcs = {
 	...,
 	.attach = fn
 };

@ depends on rule1 @
identifier rule1.fn;
identifier bridge;
statement S, S1;
@@
 int fn(
 	struct drm_bridge *bridge
+	, enum drm_bridge_attach_flags flags
 )
 {
 	... when != S
+	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+		DRM_ERROR("Fix bridge driver to make connector optional!");
+		return -EINVAL;
+	}
+
 	S1
 	...
 }

@ depends on rule1 @
identifier rule1.fn;
identifier bridge, flags;
expression E1, E2, E3;
@@
 int fn(
 	struct drm_bridge *bridge,
 	enum drm_bridge_attach_flags flags
 ) {
 <...
 drm_bridge_attach(E1, E2, E3
+	, flags
 )
 ...>
 }

@@
expression E1, E2, E3;
@@
 drm_bridge_attach(E1, E2, E3
+	, 0
 )

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226112514.12455-10-laurent.pinchart@ideasonboard.com

Use the new cec_notifier_conn_(un)register() functions to
(un)register the notifier for the HDMI connector.

Signed-off-by: Dariusz Marcinkiewicz <darekm@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017072842.16793-2-hverkuil-cisco@xs4all.nl

It is possible for one HDMI connector to have multiple CEC adapters. The
typical real-world scenario is that where one adapter is used when the
device is in standby, and one that's better/smarter when the device is
powered up.

The cec-notifier changes were made with that in mind, but I missed that in
order to support this you need to tell cec_notifier_cec_adap_unregister()
which adapter you are unregistering from the notifier.

Add this additional argument. It is currently unused, but once all drivers
use this, the CEC core will be adapted for these use-cases.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/e9fc8740-6be6-43a7-beee-ce2d7b54936e@xs4all.nl

Allow better abstraction of the drm_debug global variable in the
future. No functional changes.

Cc: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f6f65ca7e27e949533e8cd1f43c61ecac73c658e.1569329774.git.jani.nikula@intel.com

Use the new cec_notifier_cec_adap_(un)register() functions to
(un)register the notifier for the CEC adapter.

Signed-off-by: Dariusz Marcinkiewicz <darekm@google.com>
Tested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20190814104520.6001-5-darekm@google.com

We are about to add a drm_bridge_state that inherits from
drm_private_state which is defined in drm_atomic.h. Problem is,
drm_atomic.h includes drm_crtc.h which in turn includes drm_bridge.h,
leading to "drm_private_state has incomplete type" error.

Let's force all users of the drm_bridge API to explicitly include
drm_bridge.h.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190826152649.13820-2-boris.brezillon@collabora.com

Drop use of the deprecated drmP.h header file.
Fix fallout.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190804094132.29463-2-sam@ravnborg.org

Noralf needs some SPI patches in 5.3 to merge some work on tinydrm.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

Drop use of the deprecated drmP.h header file.
Fix fallout.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Francisco Jerez <currojerez@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190716064220.18157-17-sam@ravnborg.org

Drop using the deprecated drmP.h header file.
Fix fallout.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190716064220.18157-16-sam@ravnborg.org