[PATCH 07/13] opp: Allow _generic_set_opp_clk_only() to work for non-freq devices

[Dmitry Osipenko]

22.01.2021 07:35, Viresh Kumar пишет:
> On 21-01-21, 23:26, Dmitry Osipenko wrote:
>> 21.01.2021 14:17, Viresh Kumar пишет:
>>> In order to avoid conditional statements at the caller site, this patch
>>> updates _generic_set_opp_clk_only() to work for devices that don't
>>> change frequency (like power domains, etc.). Return 0 if the clk pointer
>>> passed to this routine is not valid.
>>>
>>> Signed-off-by: Viresh Kumar <viresh.kumar at linaro.org>
>>> ---
>> ...
>>
>> Hello Viresh,
>>
>> Thank you very much for yours effort! I gave a quick test to this series
>> and instantly found one small issue in this patch.
>>
>>> +	/* We may reach here for devices which don't change frequency */
>>> +	if (unlikely(!clk))
>>
>> I replaced dev_pm_opp_set_voltage() with dev_pm_opp_set_opp() in the
>> Tegra PD driver and got a crash, which happens because the above line
>> should be:
>>
>> 	if (IS_ERR(clk))
> 
> Fixed, thanks.
> 

Please remove unlikely() around IS_ERR(), it already has the unlikely().

https://elixir.bootlin.com/linux/v5.11-rc4/source/include/linux/err.h#L22

I'd also recommend to remove all the unlikely() from OPP code since it
doesn't bring any value if not used in a very performance-critical code
path. OPP core doesn't have such code paths. The [un]likely() only make
code less readable and may result in a worse assembly.