[PATCH] clk: ingenic: Fix divider calculation with div tables

From: Paul Cercueil
Date: Sat Dec 12 2020 - 08:58:41 EST


The previous code assumed that a higher hardware value always resulted
in a bigger divider, which is correct for the regular clocks, but is
an invalid assumption when a divider table is provided for the clock.

Perfect example of this is the PLL0_HALF clock, which applies a /2
divider with the hardware value 0, and a /1 divider otherwise.

Fixes: a9fa2893fcc6 ("clk: ingenic: Add support for divider tables")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.2
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
drivers/clk/ingenic/cgu.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/ingenic/cgu.c b/drivers/clk/ingenic/cgu.c
index dac6edc670cc..c8e9cb6c8e39 100644
--- a/drivers/clk/ingenic/cgu.c
+++ b/drivers/clk/ingenic/cgu.c
@@ -392,15 +392,21 @@ static unsigned int
ingenic_clk_calc_hw_div(const struct ingenic_cgu_clk_info *clk_info,
unsigned int div)
{
- unsigned int i;
+ unsigned int i, best_i = 0, best = (unsigned int)-1;

for (i = 0; i < (1 << clk_info->div.bits)
&& clk_info->div.div_table[i]; i++) {
- if (clk_info->div.div_table[i] >= div)
- return i;
+ if (clk_info->div.div_table[i] >= div &&
+ clk_info->div.div_table[i] < best) {
+ best = clk_info->div.div_table[i];
+ best_i = i;
+
+ if (div == best)
+ break;
+ }
}

- return i - 1;
+ return best_i;
}

static unsigned
--
2.29.2