[PATCH] clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

From: Codrin.Ciubotariu
Date: Mon Jun 10 2019 - 11:24:36 EST


From: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>

In clk_generated_determine_rate(), if the divisor is greater than
GENERATED_MAX_DIV + 1, then the wrong best_rate will be returned.
If clk_generated_set_rate() will be called later with this wrong
rate, it will return -EINVAL, so the generated clock won't change
its value. Do no let the divisor be greater than GENERATED_MAX_DIV + 1.

Fixes: 8c7aa6328947 ("clk: at91: clk-generated: remove useless divisor loop")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>
---
drivers/clk/at91/clk-generated.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index 5f18847965c1..290cffe35deb 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c
@@ -146,6 +146,8 @@ static int clk_generated_determine_rate(struct clk_hw *hw,
continue;

div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
+ if (div > GENERATED_MAX_DIV + 1)
+ div = GENERATED_MAX_DIV + 1;

clk_generated_best_diff(req, parent, parent_rate, div,
&best_diff, &best_rate);
--
2.20.1