diff options
authorClaudiu Beznea <>2020-01-17 13:36:46 +0200
committerGreg Kroah-Hartman <>2020-04-24 07:57:23 +0200
commita91ba793a685b58dc251cd98ff8812467c099b7a (patch)
parent8ecea3d27f7252d76953c1b968fa1af459545c56 (diff)
clk: at91: usb: continue if clk_hw_round_rate() return zero
[ Upstream commit b0ecf1c6c6e82da4847900fad0272abfd014666d ] clk_hw_round_rate() may call round rate function of its parents. In case of SAM9X60 two of USB parrents are PLLA and UPLL. These clocks are controlled by clk-sam9x60-pll.c driver. The round rate function for this driver is sam9x60_pll_round_rate() which call in turn sam9x60_pll_get_best_div_mul(). In case the requested rate is not in the proper range (rate < characteristics->output[0].min && rate > characteristics->output[0].max) the sam9x60_pll_round_rate() will return a negative number to its caller (called by clk_core_round_rate_nolock()). clk_hw_round_rate() will return zero in case a negative number is returned by clk_core_round_rate_nolock(). With this, the USB clock will continue its rate computation even caller of clk_hw_round_rate() returned an error. With this, the USB clock on SAM9X60 may not chose the best parent. I detected this after a suspend/resume cycle on SAM9X60. Signed-off-by: Claudiu Beznea <> Link: Signed-off-by: Stephen Boyd <> Signed-off-by: Sasha Levin <>
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
index 8ab8502778a2..55e09641b491 100644
--- a/drivers/clk/at91/clk-usb.c
+++ b/drivers/clk/at91/clk-usb.c
@@ -79,6 +79,9 @@ static int at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
tmp_parent_rate = req->rate * div;
tmp_parent_rate = clk_hw_round_rate(parent,
+ if (!tmp_parent_rate)
+ continue;
tmp_rate = DIV_ROUND_CLOSEST(tmp_parent_rate, div);
if (tmp_rate < req->rate)
tmp_diff = req->rate - tmp_rate;