Re: [PATCH 08/13] clk: qcom: hfpll: CLK_IGNORE_UNUSED

[Viresh Kumar]

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

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.

-- 
viresh