linux-kernel - Re: [PATCH] firmware: ti_sci: replace ifdeffery by pm_sleep

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Message-ID: <da18cd22-9f9e-4166-8a91-d5b19470c693@bootlin.com>
Date: Fri, 31 Oct 2025 09:33:17 +0100
From: Thomas Richard <thomas.richard@...tlin.com>
To: Nishanth Menon <nm@...com>
Cc: Tero Kristo <kristo@...nel.org>, Santosh Shilimkar <ssantosh@...nel.org>,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 Gregory CLEMENT <gregory.clement@...tlin.com>,
 Richard Genoud <richard.genoud@...tlin.com>, Udit Kumar <u-kumar1@...com>,
 Prasanth Mantena <p-mantena@...com>, Abhash Kumar <a-kumar2@...com>,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] firmware: ti_sci: replace ifdeffery by pm_sleep_ptr()
 macro

Hello Nishanth,

On 10/31/25 5:11 AM, Nishanth Menon wrote:
> On 10:35-20251014, Thomas Richard (TI.com) wrote:
>> Using pm_sleep_ptr() macro allows to remove ifdeffery and '__maybe_unused'
>> annotations.
>>
>> Signed-off-by: Thomas Richard (TI.com) <thomas.richard@...tlin.com>
>> ---
>>  drivers/firmware/ti_sci.c | 18 ++++++++----------
>>  1 file changed, 8 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
>> index 49fd2ae01055d0f425062147422471f0fd49e4bd..99a2e0e2960f463918950fef8829409ec365ce70 100644
>> --- a/drivers/firmware/ti_sci.c
>> +++ b/drivers/firmware/ti_sci.c
>> @@ -3706,7 +3706,7 @@ static int ti_sci_prepare_system_suspend(struct ti_sci_info *info)
>>  	}
>>  }
>>  
>> -static int __maybe_unused ti_sci_suspend(struct device *dev)
>> +static int ti_sci_suspend(struct device *dev)
>>  {
>>  	struct ti_sci_info *info = dev_get_drvdata(dev);
>>  	struct device *cpu_dev, *cpu_dev_max = NULL;
>> @@ -3746,7 +3746,7 @@ static int __maybe_unused ti_sci_suspend(struct device *dev)
>>  	return 0;
>>  }
>>  
>> -static int __maybe_unused ti_sci_suspend_noirq(struct device *dev)
>> +static int ti_sci_suspend_noirq(struct device *dev)
>>  {
>>  	struct ti_sci_info *info = dev_get_drvdata(dev);
>>  	int ret = 0;
>> @@ -3758,7 +3758,7 @@ static int __maybe_unused ti_sci_suspend_noirq(struct device *dev)
>>  	return 0;
>>  }
>>  
>> -static int __maybe_unused ti_sci_resume_noirq(struct device *dev)
>> +static int ti_sci_resume_noirq(struct device *dev)
>>  {
>>  	struct ti_sci_info *info = dev_get_drvdata(dev);
>>  	int ret = 0;
>> @@ -3780,7 +3780,7 @@ static int __maybe_unused ti_sci_resume_noirq(struct device *dev)
>>  	return 0;
>>  }
>>  
>> -static void __maybe_unused ti_sci_pm_complete(struct device *dev)
>> +static void ti_sci_pm_complete(struct device *dev)
> 
> PTR_IF when CONFIG_PM_SLEEP is disabled will result in these static
> functions unused, no? should we leave __maybe_unused as is?

PTR_IF is ((cond) ? ptr : NULL)

If CONFIG_PM_SLEEP is disabled, after preprocessor step you will have

	.suspend = 0 ? ti_sci_suspend : NULL,

So ti_sci_suspend() is still used. But as the condition is always false,
the compiler can do some optimization by removing ti_sci_suspend().

PTR_IF macro has a great documentation [1] which describes this use case.

[1]
https://elixir.bootlin.com/linux/v6.17.5/source/include/linux/util_macros.h#L85-L136

Best Regards,
Thomas