On 10/20/21 1:03 PM, Chandrasekhar L wrote:
Thanks Lukasz for comment.
For any reason (ex: HW dependency, etc), if init_call level of cpufreq/devfreq driver changed
prior to fs_init call, we would land there right?
It's not the same triggering point, so we should be safe.
One of such example is, 'drivers/cpufreq/qcom-cpufreq-hw.c' uses postcore_initcall().
It uses the postcore_initcall to probe and register a driver into
the cpufreq framework. Then the cpufreq framework later constructs the
'policy' and calls your cpufreq_driver::init() function that your
driver provided during registration. Thus, these are two different
phases. It used to be true that if a driver required to use an
'advanced' EM registration with custom private 'em_data_callback',
we put the registration call into that .init() code [1] (old [2]).
Recently Viresh added a dedicated callback for this, which IMO
is good and avoids confusion where to put that custom registration
code.
In your driver code, there is also this callback but using a
generic function [3]. It's a 'simple' EM, which is based on OPP
framework helper. A few drivers use that option, if their platform
doesn't need the 'advanced' EM (but that's not in $subject).
Regards,
Lukasz
[1]
https://elixir.bootlin.com/linux/v5.15-rc1/source/drivers/cpufreq/scmi-cpufreq.c#L249
[2]
https://elixir.bootlin.com/linux/v5.14/source/drivers/cpufreq/scmi-cpufreq.c#L192
[3]
https://elixir.bootlin.com/linux/v5.15-rc6/source/drivers/cpufreq/qcom-cpufreq-hw.c#L561
