Basically check for both +ive and -ive deviation from target clock and
pick the one with minimal error. If we get a direct match, break from
loop to acheive some optimization.
Signed-off-by: Vijayakumar Balakrishnan <vijayakumar.balakrishnan@xxxxxxxxx>
Signed-off-by: Shobhit Kumar <shobhit.kumar@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dsi_pll.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
index 9f3e6b0..16bc6b2 100644
--- a/drivers/gpu/drm/i915/intel_dsi_pll.c
+++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
@@ -243,22 +243,32 @@ static int dsi_calc_mnp(u32 dsi_clk, struct dsi_mnp *dsi_mnp)
ref_clk = 25000;
target_dsi_clk = dsi_clk;
error = 0xFFFFFFFF;
+ tmp_error = 0xFFFFFFFF;
calc_m = 0;
calc_p = 0;
for (m = 62; m <= 92; m++) {
for (p = 2; p <= 6; p++) {
-
+ /* Find the optimal m and p divisors
+ with minimal error +/- the required clock */
calc_dsi_clk = (m * ref_clk) / p;
- if (calc_dsi_clk >= target_dsi_clk) {
- tmp_error = calc_dsi_clk - target_dsi_clk;
- if (tmp_error < error) {
- error = tmp_error;
- calc_m = m;
- calc_p = p;
- }
+ if (calc_dsi_clk == target_dsi_clk) {
+ calc_m = m;
+ calc_p = p;
+ error = 0;
+ break;
+ } else
+ tmp_error = abs(target_dsi_clk - calc_dsi_clk);
+
+ if (tmp_error < error) {
+ error = tmp_error;
+ calc_m = m;
+ calc_p = p;
}
}
+
+ if (error == 0)
+ break;
}
m_seed = lfsr_converts[calc_m - 62];
--
1.7.9.5
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