Panel rotation patches

Hello!

This series adds support for display panel's DT rotation property. It's a continuation of the work that was initially started by Derek Basehore for the panel driver that is used by some Mediatek device [1]. I picked up the Derek's patches and added my t-b and r-b tags to them, I also added rotation support to the panel-lvds and panel-simple drivers.

We need the rotation support for the Nexus 7 tablet device which is now supported by the upstream kernel, the device has display panel mounted upside-down and it uses panel-lvds [2].

[1] https://lkml.org/lkml/2020/3/5/1119
[2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm/boot/dts/tegra30-asus-nexus7-grouper-common.dtsi?#n1036

Changelog:

v12: - No code changes. The v11 missed v5.9 release, re-sending patches
for the v5.10 kernel. Please review and apply patches to linux-next, thanks in advance!

v11: - This series is factored out from this patchset [3] because these
patches do not have hard dependency on the Tegra DRM patches and it should be nicer to review and apply the properly grouped patches.

- Initially [3] only touched the panel-lvds driver and Emil Velikov suggested that it will be better to support more panels in the review comments to [3]. So I included the Derek's patch for the BOE panel and added rotation support to the panel-simple driver. I tested that panel-lvds and panel-simple work properly with the rotated panel using the Opentegra Xorg driver [4] and Wayland Weston [5].

- The panel-lvds driver now prints a error message if rotation property fails to be parsed.

[3] https://lore.kernel.org/lkml/[email protected]/
[4] https://github.com/grate-driver/xf86-video-opentegra/commit/28eb20a3959bbe5bc3a3b67e55977093fd5114ca
[5] https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/315

Derek Basehore (2):
drm/panel: Add helper for reading DT rotation drm/panel: Read panel orientation for BOE TV101WUM-NL6

Dmitry Osipenko (2):
drm/panel: lvds: Read panel orientation
drm/panel-simple: Read panel orientation

 drivers/gpu/drm/drm_panel.c                   | 43 +++++++++++++++++++
 .../gpu/drm/panel/panel-boe-tv101wum-nl6.c    |  6 +++
 drivers/gpu/drm/panel/panel-lvds.c            | 10 +++++
 drivers/gpu/drm/panel/panel-simple.c          | 11 +++++
 include/drm/drm_panel.h                       |  9 ++++
 5 files changed, 79 insertions(+)

2.27.0