From 63f5c3b2b18dcaca0fc8983b52a3f5d4d70a0590 Mon Sep 17 00:00:00 2001 From: Mike Turquette Date: Wed, 2 May 2012 16:23:43 -0700 Subject: [PATCH] clk: prevent spurious parent rate propagation Patch 'clk: always pass parent_rate into .round_rate' made a subtle change to the semantics of .round_rate. It is now expected for the parent's rate to always be passed in, simplifying the implemenation of various .round_rate callback definitions. However the patch also introduced a bug in clk_calc_new_rates whereby a clock without the CLK_SET_RATE_PARENT flag set could still propagate a rate change up to a parent clock if the the .round_rate callback modified the &best_parent_rate value in any way. This patch fixes the issue at the framework level (in clk_calc_new_rates) by specifically handling the case where the CLK_SET_RATE_PARENT flag is not set. Signed-off-by: Mike Turquette Acked-by: Sascha Hauer --- drivers/clk/clk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8149764f8438..7ceca0e8645a 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -774,12 +774,18 @@ static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) if (IS_ERR_OR_NULL(clk)) return NULL; + /* save parent rate, if it exists */ + if (clk->parent) + best_parent_rate = clk->parent->rate; + /* never propagate up to the parent */ if (!(clk->flags & CLK_SET_RATE_PARENT)) { if (!clk->ops->round_rate) { clk->new_rate = clk->rate; return NULL; } + new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); + goto out; } /* need clk->parent from here on out */ @@ -795,7 +801,6 @@ static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) goto out; } - best_parent_rate = clk->parent->rate; new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); if (best_parent_rate != clk->parent->rate) { -- 2.30.2