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| author | Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> | 2025-04-08 16:54:25 +0300 |
|---|---|---|
| committer | Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com> | 2025-04-15 14:05:14 +0300 |
| commit | fec450ca15af63649e219060f37a8ec673333726 (patch) | |
| tree | f9d5988e63671cdf3b58833d3d054cfdb20b4cb9 /include/drm | |
| parent | f8cc87024d1a1261f71dd2413951b87875b3422f (diff) | |
| download | linux-fec450ca15af63649e219060f37a8ec673333726.tar.xz | |
drm/display: hdmi: provide central data authority for ACR params
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>
Diffstat (limited to 'include/drm')
| -rw-r--r-- | include/drm/display/drm_hdmi_helper.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/drm/display/drm_hdmi_helper.h b/include/drm/display/drm_hdmi_helper.h index 57e3b18c15ec..09145c9ee9fc 100644 --- a/include/drm/display/drm_hdmi_helper.h +++ b/include/drm/display/drm_hdmi_helper.h @@ -28,4 +28,10 @@ unsigned long long drm_hdmi_compute_mode_clock(const struct drm_display_mode *mode, unsigned int bpc, enum hdmi_colorspace fmt); +void +drm_hdmi_acr_get_n_cts(unsigned long long tmds_char_rate, + unsigned int sample_rate, + unsigned int *out_n, + unsigned int *out_cts); + #endif |