drm/tilcdc: Remove obsolete crtc_mode_valid() hack

Earlier there were no mode_valid() helper for crtc and tilcdc had a
hack to over come this limitation. But now the mode_valid() helper is
there (has been since v4.13), so it is about time to get rid of that
hack.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ <5c4dcb5b1e7975bd2b7ca86f7addf219cd0f9a06.1564750248.git.jsarha@ti.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 503 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drm/tilcdc: Add drm bridge support for attaching drm bridge drivers

Adds drm bride support for attaching drm bridge drivers to tilcdc. The
decision whether a video port leads to an external encoder or bridge
is made simply based on remote device's compatible string. The code
has been tested with BeagleBone-Black with and without BeagleBone
DVI-D Cape Rev A3 using ti-tfp410 driver.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drm/tilcdc: Choose console BPP that supports RGB

Choose console BPP that supports RGB and remove the old fbdev bpp
selection code. LCDC on AM335x has red and blue wires switched between
24 bit and 16 bit colors. If 24 format is wired for RGB colors, the 16
bit format is wired for BGR. drm_fbdev_cma_init() does not currently
like anything else but RGB formats, so we must choose such bytes per
pixel value that supports RGB.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drm/tilcdc: Add support for external tda998x encoder

Add support for an external compontised DRM encoder. The external
encoder can be connected to tilcdc trough device tree graph binding.
The binding document for tilcdc has been updated. The current
implementation supports only tda998x encoder.

To be able to filter out the unsupported video modes the tilcdc driver
needs to hijack the external connectors helper functions. The tilcdc
installes new helper functions that are otherwise identical to
orignals, but the mode_valid() call-back check the mode first localy,
before calling the original call-back. The tilcdc dirver restores the
original helper functions before it is unbound from the external
device.

I got the idea and some lines of code from Jean-Francois Moine's
"drm/tilcdc: Change the interface with the tda998x driver"-patch.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>