On 1/17/19 11:08, Viresh Kumar wrote:

On 17-01-19, 09:38, Jorge Ramirez wrote:

quoted

COMMON_CLK_DISABLED_UNUSED relies on the enable_count reference counter
to disable the clocks that were enabled by the firwmare and not by the
drivers.

the cpufreq driver does not enable the cpu clock.

so when clk_change_rate is called, the enable_count counter is not
incremented and therefore it just remains null since this was enabled by
the firmware.

I tried doing:

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index e58bfcb..5a9f83e 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c

@@ -124,6 +124,10 @@ static int resources_available(void)
                return ret;
        }

+ ret = clk_prepare_enable(cpu_clk);
+ if (ret)
+         return ret;
+
        clk_put(cpu_clk);

        name = find_supply_name(cpu_dev);

and that removed the need for CLK_IGNORE_UNUSED. But I am not sure of
the system wide consequences of that change to cpufreq.

If the cpufreq driver enables it then it should disable it on exit as
well, right ? And in that case if you unload your driver's module, you
will hang the system as the clock will get disabled :)

ah, of course, sorry was over-thinking this thing :)

Every other platform must either be marking it with CLK_IGNORE_UNUSED
or they must be doing clk_enable from somewhere, maybe the CPU online
path, not sure though.

since this clock is enabled by the firmware, it seems to me that using
CLK_IGNORE_UNUSED remains the best option.


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