Re: [PATCH 08/13] clk: qcom: hfpll: CLK_IGNORE_UNUSED
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2019-01-17 10:08:14
Also in:
linux-arm-kernel, linux-clk, lkml
On 17-01-19, 09:38, Jorge Ramirez wrote:
quoted hunk ↗ jump to hunk
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