diff mbox series

[v4] clk: renesas: rzg2l: Fix FOUTPOSTDIV clk

Message ID 20241024134236.315289-1-biju.das.jz@bp.renesas.com (mailing list archive)
State Under Review
Headers show
Series [v4] clk: renesas: rzg2l: Fix FOUTPOSTDIV clk | expand

Commit Message

Biju Das Oct. 24, 2024, 1:42 p.m. UTC 
While computing foutpostdiv_rate, the value of params->pl5_fracin
is discarded, which results in the wrong refresh rate. Fix the formula
for computing foutpostdiv_rate.

Fixes: 1561380ee72f ("clk: renesas: rzg2l: Add FOUTPOSTDIV clk support")
Signed-off-by: Hien Huynh <hien.huynh.px@renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
Changes in v4:
 * Used div_u64() helper as the division is a 64-by-32 division.
Changes in v3:
 * Used mul_u32_u32() for 32-bit multiplication.
Changes in v2:
 * Improved the precision by division of params->pl5_refdiv
   done after all multiplication.
---
 drivers/clk/renesas/rzg2l-cpg.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 88bf39e8c79c..b43b763dfe18 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -548,7 +548,7 @@  static unsigned long
 rzg2l_cpg_get_foutpostdiv_rate(struct rzg2l_pll5_param *params,
 			       unsigned long rate)
 {
-	unsigned long foutpostdiv_rate;
+	unsigned long foutpostdiv_rate, foutvco_rate;
 
 	params->pl5_intin = rate / MEGA;
 	params->pl5_fracin = div_u64(((u64)rate % MEGA) << 24, MEGA);
@@ -557,10 +557,11 @@  rzg2l_cpg_get_foutpostdiv_rate(struct rzg2l_pll5_param *params,
 	params->pl5_postdiv2 = 1;
 	params->pl5_spread = 0x16;
 
-	foutpostdiv_rate =
-		EXTAL_FREQ_IN_MEGA_HZ * MEGA / params->pl5_refdiv *
-		((((params->pl5_intin << 24) + params->pl5_fracin)) >> 24) /
-		(params->pl5_postdiv1 * params->pl5_postdiv2);
+	foutvco_rate = div_u64(mul_u32_u32(EXTAL_FREQ_IN_MEGA_HZ * MEGA,
+					   (params->pl5_intin << 24) + params->pl5_fracin),
+			       params->pl5_refdiv) >> 24;
+	foutpostdiv_rate = DIV_ROUND_CLOSEST_ULL(foutvco_rate,
+						 params->pl5_postdiv1 * params->pl5_postdiv2);
 
 	return foutpostdiv_rate;
 }