Re: [PATCH 4/4] iio: auxadc: mediatek: change to subsys_initcall

Chun-Hung Wu
2019-05-20T06:06:38Z

Hi Jonathan,

On Sat, 2019-05-18 at 11:36 +0100, Jonathan Cameron wrote:
> On Thu, 16 May 2019 16:10:47 +0800
> Chun-Hung Wu <chun-hung.wu@mediatek.com> wrote:
>
> > Move auxadc platform_driver_register() from module_init
> > to subsys_initcall because auxadc user drivers
> > are all moudle drivers, need to gurantee
> > auxadc driver ready before module_init.
> >
> Is it not possible to make them use deferred handling to come
> back later if this isn't yet available?
>
> subsys_initcall often ends up being a more fragile approach.

Agreed, I will ask auxadc driver users to add deferred handling
instead of moving auxadc platform_driver_register() from module_init
to subsys_initcall.

Thanks,
Chun-hung

>
> Thanks,
>
> Jonathan
>
> > Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
> > ---
> > drivers/iio/adc/mt6577_auxadc.c | 14 +++++++++++++-
> > 1 file changed, 13 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c
> > index 58d7cb2..cb8e3dd 100644
> > --- a/drivers/iio/adc/mt6577_auxadc.c
> > +++ b/drivers/iio/adc/mt6577_auxadc.c
> > @@ -350,7 +350,19 @@ static int mt6577_auxadc_remove(struct platform_device *pdev)
> > .probe = mt6577_auxadc_probe,
> > .remove = mt6577_auxadc_remove,
> > };
> > -module_platform_driver(mt6577_auxadc_driver);
> > +
> > +static int __init mt6577_auxadc_init(void)
> > +{
> > + return platform_driver_register(&mt6577_auxadc_driver);
> > +}
> > +
> > +static void __exit mt6577_auxadc_exit(void)
> > +{
> > + platform_driver_unregister(&mt6577_auxadc_driver);
> > +}
> > +
> > +subsys_initcall(mt6577_auxadc_init);
> > +module_exit(mt6577_auxadc_exit);
> >
> > MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao@mediatek.com>");
> > MODULE_DESCRIPTION("MTK AUXADC Device Driver");
>