On Sun, May 06, 2012 at 10:08:27PM -0700, Mike Turquette wrote:
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 mturquette@linaro.org Reported-by: Sascha Hauers.hauer@pengutronix.de
I think a warning might be useful when a clk driver tries to change the parent rate even if it is not allowed to. This can be added in a later patch, so
Acked-by: Sascha Hauer s.hauer@pengutronix.de
Sascha
drivers/clk/clk.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 8149764..7ceca0e 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) { -- 1.7.5.4