[PATCH] clk: shmobile: div6: Avoid division by zero in .round_rate()

[Geert Uytterhoeven <geert+renesas@glider.be>]

Anyone may call clk_round_rate() with a zero rate value, so we have to
protect against that.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This was triggered by the bad version of "clk: Add rate constraints to
clocks", but can happen regardless, cfr.
https://lkml.org/lkml/2015/1/29/560

 drivers/clk/shmobile/clk-div6.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/clk/shmobile/clk-div6.c b/drivers/clk/shmobile/clk-div6.c
index efbaf6c81b7530b8..036a692c72195db9 100644
--- a/drivers/clk/shmobile/clk-div6.c
+++ b/drivers/clk/shmobile/clk-div6.c
@@ -90,6 +90,9 @@ static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
 {
 	unsigned int div;
 
+	if (!rate)
+		rate = 1;
+
 	div = DIV_ROUND_CLOSEST(parent_rate, rate);
 	return clamp_t(unsigned int, div, 1, 64);
 }
-- 
1.9.1