clk: renesas: rzg2l: Fix FOUTPOSTDIV clk

[ Upstream commit dabf72b85f298970e86891b5218459c17b57b26a ]

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>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20241024134236.315289-1-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 04b78064d4e01c3b70a67e52e0ff87bfd1bc21a3..640ab2cc28cfa435887d340f55e79b0183d9d681 100644 (file)
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -552,7 +552,7 @@ 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);
@@ -561,10 +561,11 @@ 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;
 }