drm/display: hdmi: provide central data authority for ACR params

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HDMI standard defines recommended N and CTS values for Audio Clock
Regeneration. Currently each driver implements those, frequently in
somewhat unique way. Provide a generic helper for getting those values
to be used by the HDMI drivers.

The helper is added to drm_hdmi_helper.c rather than drm_hdmi_audio.c
since HDMI drivers can be using this helper function even without
switching to DRM HDMI Audio helpers.

Note: currently this only handles the values per HDMI 1.4b Section 7.2
and HDMI 2.0 Section 9.2.1. Later the table can be expanded to
accommodate for Deep Color TMDS char rates per HDMI 1.4 Appendix D
and/or HDMI 2.0 / 2.1 Appendix C).

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250408-drm-hdmi-acr-v2-1-dee7298ab1af@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

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Dmitry Baryshkov 2025-04-08 16:54:25 +03:00

parent f8cc87024d

commit fec450ca15

2 changed files with 174 additions and 0 deletions

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168

drivers/gpu/drm/display/drm_hdmi_helper.c

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6

include/drm/display/drm_hdmi_helper.h

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