drm: Add a new helper drm_color_ctm_s31_32_to_qm_n()
authorjames qian wang (Arm Technology China) <james.qian.wang@arm.com>
Tue, 12 Nov 2019 11:09:59 +0000 (11:09 +0000)
committerjames qian wang (Arm Technology China) <james.qian.wang@arm.com>
Thu, 14 Nov 2019 02:29:18 +0000 (10:29 +0800)
commit7ca7fcef13f494acd6d9c880ee7fb8134ed7d116
treea78acfb5008cc2651a49746baee416350d6f00df
parent4773483568f75e650c05dc6d5086f382b9538081
drm: Add a new helper drm_color_ctm_s31_32_to_qm_n()

Add a new helper function drm_color_ctm_s31_32_to_qm_n() for driver to
convert S31.32 sign-magnitude to Qm.n 2's complement that supported by
hardware.

V4: Address Mihai, Daniel and Ilia's review comments.
V5: Includes the sign bit in the value of m (Qm.n).
V6: Allows m = 0 according to Mihail's comments.
V7: Address Mihail's comments.
V8: Use type 'u32' to replace 'uint32_t'
V9: Rebase.

Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@arm.com>
Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191112110927.20931-2-james.qian.wang@arm.com
drivers/gpu/drm/drm_color_mgmt.c
include/drm/drm_color_mgmt.h