[PATCH 1/9] drm/i915: Add helper to compute link M/N ratio for reuse

[Ankit Nautiyal <ankit.k.nautiyal@intel.com>]

Introduce `intel_display_get_link_m_n()` to compute the link M/N ratio
based on pixel clock and link 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.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 456fc4b04cda..671491a2a3b6 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2506,13 +2506,24 @@ static void compute_m_n(u32 *ret_m, u32 *ret_n,
 	intel_reduce_m_n_ratio(ret_m, ret_n);
 }
 
+static
+void intel_display_get_link_m_n(u32 *link_m, u32 *link_n,
+				u32 pixel_clock,
+				u32 link_clock)
+{
+	u32 link_symbol_clock = intel_dp_link_symbol_clock(link_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);
@@ -2529,9 +2540,8 @@ 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_get_link_m_n(&m_n->link_m, &m_n->link_n,
+				   pixel_clock, link_clock);
 }
 
 void intel_panel_sanitize_ssc(struct intel_display *display)
-- 
2.45.2