From: Paul Cercueil <paul@crapouillou.net>
To: Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>
Cc: od@zcrc.me, linux-clk@vger.kernel.org,
linux-kernel@vger.kernel.org,
Paul Cercueil <paul@crapouillou.net>,
stable@vger.kernel.org
Subject: [PATCH] clk: ingenic: Fix divider calculation with div tables
Date: Sat, 12 Dec 2020 13:57:33 +0000 [thread overview]
Message-ID: <20201212135733.38050-1-paul@crapouillou.net> (raw)
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@vger.kernel.org> # 5.2
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
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
next reply other threads:[~2020-12-12 13:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-12 13:57 Paul Cercueil [this message]
2020-12-20 0:05 ` [PATCH] clk: ingenic: Fix divider calculation with div tables Stephen Boyd
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