drm/i915/ddi: add helper to compute DDI clock frequency

Add intel_ddi_link_symbol_clock() to return the DDI clock frequency for
a given port clock:
  DP 8b/10b : rate
  DP 128b/132b (UHBR) : (10 / 32) * rate
  HDMI FRL  : (10 / 18) * rate
  HDMI TMDS : rate

The DP case reuses intel_dp_link_symbol_clock().
This will help in upcoming commits to decide value to be written
in DDI_CLK_VALFREQ.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260811175844.2613721-2-suraj.kandpal@intel.com
This commit is contained in:
Suraj Kandpal 2026-08-11 23:28:42 +05:30
commit 5abc20e39d
2 changed files with 12 additions and 0 deletions