On Tue, 27 Jun 2017, Dirk Behme wrote: > On 11.02.2016 01:43, Michael Turquette wrote: > > Quoting Lee Jones (2016-01-18 06:28:50) > > > Signed-off-by: Lee Jones <lee.jo...@linaro.org> > > > > Looks good to me. > > > > Regards, > > Mike > > > > > --- > > > drivers/clk/clk.c | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > > > index 835cb85..178b364 100644 > > > --- a/drivers/clk/clk.c > > > +++ b/drivers/clk/clk.c > > > @@ -575,6 +575,9 @@ static void clk_core_unprepare(struct clk_core *core) > > > if (WARN_ON(core->prepare_count == 0)) > > > return; > > > + if (WARN_ON(core->prepare_count == 1 && core->flags & > > > CLK_IS_CRITICAL)) > > > + return; > > > + > > > if (--core->prepare_count > 0) > > > return; > > > @@ -680,6 +683,9 @@ static void clk_core_disable(struct clk_core *core) > > > if (WARN_ON(core->enable_count == 0)) > > > return; > > > + if (WARN_ON(core->enable_count == 1 && core->flags & > > > CLK_IS_CRITICAL)) > > > + return; > > > + > > > if (--core->enable_count > 0) > > > return; > > > I have a question regarding this patch, which is mainline meanwhile [1]: > > Having the following clock configuration: > > |--> child clk '1' (crit) > clk source --> parent clk 'A' (crit) -->| > |--> child clk '2' > > > Clock '2' might be used, or not. It might be disabled or not. It doesn't > matter. Clock '1' is not allowed to be disabled. Therefore its marked as > critical. > > Parent clock 'A' is marked as critical because its not allowed to be > disabled, even if the enable_count of all child clocks is 0. To avoid that > by disabling parent clock 'A' the child clock '1' is disabled, too, whats > not allowed as its marked as critical. > > > Now, child clock '2' is used and enabled & disabled continuously by a (SPI) > driver. What is ok. But: > > Disabling child clock '2' results in the attempt to disable parent clock > 'A', too, which has correct enable_count 1 (from enabling the child '2'). > What results > > a) in the WARN_ON output > > and > > b) enable_count of 'A' never decreases to 0. Being off by one after the > WARN_ON > > > It sounds like both is wrong for a configuration like above.
Clock A still has one user, Clock 1. Why is that wrong? > Opinions or proposal how to fix/change this? > > > Best regards > > Dirk > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/clk/clk.c?id=2e20fbf592621b2c2aeddd82e0fa3dad053cce03 -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
