drm: merge commit related to gamma [1/1]

drm: merge commit related to gamma [1/1]

PD#SWPL-11059

Problem:
gamma setting in DRM

Solution:
merge commit related to gamma

Author: Ao Xu <ao.xu@amlogic.com>
Date:   Tue Oct 30 19:18:21 2018 +0800

    drm: add meson private property gamma_lut

    When setting CTM, gamma is also set again.
    Setting gamma frequently will lead to visual glitches.
    Add a private value to record whether
    gamma_lut blob is changed.

    Bug: b/113682067
    Test: Ran on device and changed gamma to verify there are no glitches

Author: Fergus Simpson <afergs@google.com>
Date:   Fri Aug 10 13:18:36 2018 -0700

    [Estelle] Enable top/bottom color clamping

    Modifies amvecm's color clipping to allow either the lower or upper
    limit to be set. This sets clipping registers that hold the top and
    bottom 10-bit clipping values for each color channel.

    This does not cause the artifacts that we've been seeing while trying
    enable the gamma tables.

    Usage (set a clip of 32/255):
    echo 20080020 > /sys/class/amvecm/color_bottom

    Bug: 109942195
    Test: Flashed to device and tested with a internal changes that use the
          registers.

Author: Frank Chen <frank.chen@amlogic.com>
Date:   Wed Aug 8 15:21:17 2018 +0800

    remove gamma_enable in am_meson_crtc_create

Verify:
verify by u200

Change-Id: I4221b3b4671516e7afd4dea14ce3cd71b4b66433
Signed-off-by: Dezhi Kong <dezhi.kong@amlogic.com>