Support low-active hotplug detect signals by storing the GPIO flags
parsed from device tree.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Implement initial atomic state handling. Hook up the CRTCs, planes' and
connectors' ->atomic_destroy_state() callback to ensure that the atomic
state objects don't leak.

Furthermore the CRTC now implements the ->mode_set_nofb() callback that
is used by new helpers to implement ->mode_set() and ->mode_set_base().
These new helpers also make use of the new plane helper functions which
the driver now provides.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The tegra_output_exit() and tegra_output_remove() functions cannot fail,
so make them return void.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The tegra_output midlayer is now completely gone and output drivers use
it purely as a helper library.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Implement encoder and connector within the eDP driver itself using the
Tegra output helpers rather than using the Tegra output as midlayer. By
doing so one level of indirection is removed and output drivers become
more flexible while keeping the majority of the advantages provided by
the common output helpers.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Implement encoder and connector within the DSI driver itself using the
Tegra output helpers rather than using the Tegra output as midlayer. By
doing so one level of indirection is removed and output drivers become
more flexible while keeping the majority of the advantages provided by
the common output helpers.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Implement encoder and connector within the HDMI driver itself using the
Tegra output helpers rather than using the Tegra output as midlayer. By
doing so one level of indirection is removed and output drivers become
more flexible while keeping the majority of the advantages provided by
the common output helpers.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Implement encoder and connector within the RGB driver itself using the
Tegra output helpers rather than using the Tegra output as midlayer. By
doing so one level of indirection is removed and output drivers become
more flexible while keeping the majority of the advantages provided by
the common output helpers.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The output layer was initially designed to help reduce the amount of
code duplicated in output drivers. An unfortunate side-effect of that
was that it turned into a midlayer and it became difficult to make the
output drivers work without bending over backwards to fit into the
midlayer.

This commit starts to convert the midlayer into a helper library by
exporting most of the common functions so that they can be used by the
output drivers directly. Doing so will allow output drivers to reuse
common code paths but more easily override them where necessary.

Signed-off-by: Thierry Reding <treding@nvidia.com>

The DRM core now zeroes out the memory associated with CRTC, encoder and
connector objects upon cleanup, so there's no need to explicitly do that
in drivers anymore.

Signed-off-by: Thierry Reding <treding@nvidia.com>