[PATCH v3 01/10] drm/i915/display: Add helper to compute link M/N ratio for reuse

[Suraj Kandpal <suraj.kandpal@intel.com>]

From: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

Introduce intel_display_compute_link_m_n() to compute the link M/N ratio
from the pixel clock and the link symbol clock. This logic was
previously embedded within intel_link_compute_m_n().

The new helper allows reuse of link M/N computation in other contexts
without requiring the full data M/N calculation.

No functional changes intended.

v2:
- Rename function (Jani)
- The link symbol clock is passed in rather than derived here, so that the
DP specific conversion from the link rate stays with the caller. (Jani)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 9151ea6c15ab..f04a6f97e05a 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2641,13 +2641,20 @@ static void compute_m_n(u32 *ret_m, u32 *ret_n,
 	intel_reduce_m_n_ratio(ret_m, ret_n);
 }
 
+static void intel_display_compute_link_m_n(u32 *link_m, u32 *link_n,
+					   int pixel_clock, int link_symbol_clock)
+{
+	compute_m_n(link_m, link_n,
+		    pixel_clock, link_symbol_clock,
+		    0x80000);
+}
+
 void
 intel_link_compute_m_n(u16 bits_per_pixel_x16, int nlanes,
 		       int pixel_clock, int link_clock,
 		       int bw_overhead,
 		       struct intel_link_m_n *m_n)
 {
-	u32 link_symbol_clock = intel_dp_link_symbol_clock(link_clock);
 	u32 data_m = intel_dp_effective_data_rate(pixel_clock, bits_per_pixel_x16,
 						  bw_overhead);
 	u32 data_n = drm_dp_max_dprx_data_rate(link_clock, nlanes);
@@ -2664,9 +2671,9 @@ intel_link_compute_m_n(u16 bits_per_pixel_x16, int nlanes,
 		    data_m, data_n,
 		    0x8000000);
 
-	compute_m_n(&m_n->link_m, &m_n->link_n,
-		    pixel_clock, link_symbol_clock,
-		    0x80000);
+	intel_display_compute_link_m_n(&m_n->link_m, &m_n->link_n,
+				       pixel_clock,
+				       intel_dp_link_symbol_clock(link_clock));
 }
 
 void intel_panel_sanitize_ssc(struct intel_display *display)
-- 
2.34.1