Sachin Kamat reports that "component: add support for component match
array" broke Exynos DRM due to a NULL pointer deref.  Fix this.
Reported-by: NSachin Kamat <sachin.kamat@samsung.com>
Tested-by: NSachin Kamat <sachin.kamat@samsung.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add support for generating a set of component matches at master probe
time, and submitting them to the component layer.  This allows the
component layer to perform the matches internally without needing to
call into the master driver, and allows for further restructuring of
the component helper.
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Permit masters to call component_master_add_child() and match the same
child multiple times.  This may happen if there's multiple connections
to a single component device from other devices.  In such scenarios,
we should not return a failure, but instead ignore the attempt.
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In try_to_bring_up_master(), we tear down the master's component list
for each error case, except for devres group failure.  Fix this
oversight by making the code less prone to such mistakes.
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We weren't handling the devres issues for the master device failing a
bind, or being unbound properly.  Add a devres group to contain these,
and release the resources at the appropriate points.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Subsystems such as ALSA, DRM and others require a single card-level
device structure to represent a subsystem.  However, firmware tends to
describe the individual devices and the connections between them.

Therefore, we need a way to gather up the individual component devices
together, and indicate when we have all the component devices.

We do this in DT by providing a "superdevice" node which specifies
the components, eg:

	imx-drm {
		compatible = "fsl,drm";
		crtcs = <&ipu1>;
		connectors = <&hdmi>;
	};

The superdevice is declared into the component support, along with the
subcomponents.  The superdevice receives callbacks to locate the
subcomponents, and identify when all components are present.  At this
point, we bind the superdevice, which causes the appropriate subsystem
to be initialised in the conventional way.

When any of the components or superdevice are removed from the system,
we unbind the superdevice, thereby taking the subsystem down.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>