[PATCH] rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

[PATCH] rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

[Anson Huang]

Use __maybe_unused for power management related functions
instead of #if CONFIG_PM_SLEEP to simply the code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 drivers/rtc/rtc-snvs.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index e0edd594..2a2b8da 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -360,9 +360,7 @@ static int snvs_rtc_probe(struct platform_device *pdev)
 	return ret;
 }
 
-#ifdef CONFIG_PM_SLEEP
-
-static int snvs_rtc_suspend_noirq(struct device *dev)
+static int __maybe_unused snvs_rtc_suspend_noirq(struct device *dev)
 {
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 
@@ -372,7 +370,7 @@ static int snvs_rtc_suspend_noirq(struct device *dev)
 	return 0;
 }
 
-static int snvs_rtc_resume_noirq(struct device *dev)
+static int __maybe_unused snvs_rtc_resume_noirq(struct device *dev)
 {
 	struct snvs_rtc_data *data = dev_get_drvdata(dev);
 
@@ -387,14 +385,6 @@ static const struct dev_pm_ops snvs_rtc_pm_ops = {
 	.resume_noirq = snvs_rtc_resume_noirq,
 };
 
-#define SNVS_RTC_PM_OPS	(&snvs_rtc_pm_ops)
-
-#else
-
-#define SNVS_RTC_PM_OPS	NULL
-
-#endif
-
 static const struct of_device_id snvs_dt_ids[] = {
 	{ .compatible = "fsl,sec-v4.0-mon-rtc-lp", },
 	{ /* sentinel */ }
@@ -404,7 +394,7 @@ MODULE_DEVICE_TABLE(of, snvs_dt_ids);
 static struct platform_driver snvs_rtc_driver = {
 	.driver = {
 		.name	= "snvs_rtc",
-		.pm	= SNVS_RTC_PM_OPS,
+		.pm	= &snvs_rtc_pm_ops,
 		.of_match_table = snvs_dt_ids,
 	},
 	.probe		= snvs_rtc_probe,
-- 
2.7.4

RE: [PATCH] rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

[Aisheng Dong]

> From: Anson Huang
> Sent: Monday, April 29, 2019 3:03 PM
> 
> Use __maybe_unused for power management related functions instead of #if
> CONFIG_PM_SLEEP to simply the code.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>

Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Regards
Dong Aisheng

Re: [PATCH] rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

[Trent Piepho]

On Mon, 2019-04-29 at 07:02 +0000, Anson Huang wrote:
> Use __maybe_unused for power management related functions
> instead of #if CONFIG_PM_SLEEP to simply the code.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>

This will result in the functions always being included, even if
PM_SLEEP is off...

>  
> @@ -387,14 +385,6 @@ static const struct dev_pm_ops snvs_rtc_pm_ops = {
>  	.resume_noirq = snvs_rtc_resume_noirq,
>  };

...because they will always be used by the definition of
snvs_rtc_pm_ops here.

In order for this to work, SIMPLE_DEV_PM_OPS() needs to be used,
so that the dev_pm_ops struct is empty when PM is off and the functions
don't get referenced. See: https://lkml.org/lkml/2019/1/17/376

RE: [PATCH] rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

[Anson Huang]

Hi, Trent

> -----Original Message-----
> From: Trent Piepho [mailto:tpiepho@impinj.com]
> Sent: Tuesday, April 30, 2019 1:13 AM
> To: linux-rtc@vger.kernel.org; Anson Huang <anson.huang@nxp.com>;
> a.zummo@towertech.it; linux-kernel@vger.kernel.org;
> alexandre.belloni@bootlin.com
> Cc: dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH] rtc: snvs: Use __maybe_unused instead of #if
> CONFIG_PM_SLEEP
> 
> On Mon, 2019-04-29 at 07:02 +0000, Anson Huang wrote:
> > Use __maybe_unused for power management related functions instead of
> > #if CONFIG_PM_SLEEP to simply the code.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> 
> This will result in the functions always being included, even if PM_SLEEP is
> off...
> 
> >
> > @@ -387,14 +385,6 @@ static const struct dev_pm_ops snvs_rtc_pm_ops
> = {
> >  	.resume_noirq = snvs_rtc_resume_noirq,  };
> 
> ...because they will always be used by the definition of snvs_rtc_pm_ops
> here.

You are right, I missed this part, have sent out V2 patch with 
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() used to define the ops, please help review.

Thanks,
Anson.

> 
> In order for this to work, SIMPLE_DEV_PM_OPS() needs to be used, so that
> the dev_pm_ops struct is empty when PM is off and the functions don't get
> referenced. See:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.o
> rg%2Flkml%2F2019%2F1%2F17%2F376&amp;data=02%7C01%7Canson.huan
> g%40nxp.com%7C5b5aea8d276d4a3e195008d6ccc5e1b5%7C686ea1d3bc2b4
> c6fa92cd99c5c301635%7C0%7C1%7C636921547599787617&amp;sdata=K8jv
> KXTCIPw4IDgx8aA2Nn%2Fs64FiSpmf7GVuzuXulbI%3D&amp;reserved=0