fsl-ftm-alarm driver can be built out of tree, so change the
macro device_initcall() to module_init() for standard usage.

fsl-ftm-alarm registers a platform driver in module_init function,
however there is no module_exit function to unregister it, and it will
occur resource leak, so add ftm_alarm_exit() function for module_exit.

Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com>
---
v3:
- add semicolon after module_init and module_exit to keep the format
consistent
v2:
- modify the commit message for more accurate description
---
 drivers/rtc/rtc-fsl-ftm-alarm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-fsl-ftm-alarm.c b/drivers/rtc/rtc-fsl-ftm-alarm.c
index c0df49fb978c..7fabfc098299 100644
--- a/drivers/rtc/rtc-fsl-ftm-alarm.c
+++ b/drivers/rtc/rtc-fsl-ftm-alarm.c
@@ -332,7 +332,13 @@ static int __init ftm_alarm_init(void)
 	return platform_driver_register(&ftm_rtc_driver);
 }
 
-device_initcall(ftm_alarm_init);
+static void __exit ftm_alarm_exit(void)
+{
+	platform_driver_unregister(&ftm_rtc_driver);
+}
+
+module_init(ftm_alarm_init);
+module_exit(ftm_alarm_exit);
 
 MODULE_DESCRIPTION("NXP/Freescale FlexTimer alarm driver");
 MODULE_AUTHOR("Biwen Li <biwen.li@nxp.com>");
-- 
2.31.0

On 05/09/2022 08.26, Zhang Jianhua wrote:
> fsl-ftm-alarm driver can be built out of tree, so change the
> macro device_initcall() to module_init() for standard usage.

"out of tree" usually refers to modules that are not part of the
mainline kernel.

"can be built as a module" is more accurate and less confusing.

> fsl-ftm-alarm registers a platform driver in module_init function,
> however there is no module_exit function to unregister it, and it will
> occur resource leak, so add ftm_alarm_exit() function for module_exit.

It seems that you can avoid a lot of boilerplate using the
module_platform_driver macro. The single line

module_platform_driver(ftm_rtc_driver);

should/could replace the ftm_alarm_init/ftm_alarm_exit functions and the
explicit module_init()/module_exit() lines.

Rasmus

This is a good idea, thanks.

在 2022/9/5 21:17, Rasmus Villemoes 写道:
> On 05/09/2022 08.26, Zhang Jianhua wrote:
>> fsl-ftm-alarm driver can be built out of tree, so change the
>> macro device_initcall() to module_init() for standard usage.
> "out of tree" usually refers to modules that are not part of the
> mainline kernel.
>
> "can be built as a module" is more accurate and less confusing.
>
>> fsl-ftm-alarm registers a platform driver in module_init function,
>> however there is no module_exit function to unregister it, and it will
>> occur resource leak, so add ftm_alarm_exit() function for module_exit.
> It seems that you can avoid a lot of boilerplate using the
> module_platform_driver macro. The single line
>
> module_platform_driver(ftm_rtc_driver);
>
> should/could replace the ftm_alarm_init/ftm_alarm_exit functions and the
> explicit module_init()/module_exit() lines.
>
> Rasmus