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In-Reply-To: <b369e6d44b01e0ccc653e333bc2def556b17bbb3.camel@intel.com>
From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 8 Nov 2022 14:09:07 +0100
Message-ID: <CAJZ5v0gavPhs5wqhE0VOrhydbqVgC4BSRxN-aGPmAP2a2k_WhA@mail.gmail.com>
Subject: Re: [PATCH v1 1/5] rtc: rtc-cmos: Call cmos_wake_setup() from cmos_do_probe()
To:     Zhang Rui <rui.zhang@intel.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        linux-rtc@vger.kernel.org, Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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Precedence: bulk

On Tue, Nov 8, 2022 at 3:31 AM Zhang Rui <rui.zhang@intel.com> wrote:
>
> On Mon, 2022-11-07 at 20:59 +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Notice that cmos_wake_setup() is the only user of acpi_rtc_info and
> > it
> > can operate on the cmos_rtc variable directly, so it need not set the
> > platform_data pointer before cmos_do_probe() is called.  Instead, it
> > can be called by cmos_do_probe() in the case when the platform_data
> > pointer is not set to implement the default behavior (which is to use
> > the FADT information as long as ACPI support is enabled).
> >
>
> ...
>
> >
> > @@ -827,19 +829,27 @@ cmos_do_probe(struct device *dev, struct
> >               if (info->address_space)
> >                       address_space = info->address_space;
> >
> > -             if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
> > -                     cmos_rtc.day_alrm = info->rtc_day_alarm;
> > -             if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
> > -                     cmos_rtc.mon_alrm = info->rtc_mon_alarm;
> > -             if (info->rtc_century && info->rtc_century < 128)
> > -                     cmos_rtc.century = info->rtc_century;
> > +             cmos_rtc.day_alrm = info->rtc_day_alarm;
> > +             cmos_rtc.mon_alrm = info->rtc_mon_alarm;
> > +             cmos_rtc.century = info->rtc_century;
> >
> >               if (info->wake_on && info->wake_off) {
> >                       cmos_rtc.wake_on = info->wake_on;
> >                       cmos_rtc.wake_off = info->wake_off;
> >               }
> > +     } else {
> > +             cmos_wake_setup(dev);
> >       }
> >
> >
>
> Previously, before commit a474aaedac99 ("rtc-cmos: move wake setup from
> ACPI glue into RTC driver"), dev->platform_data is set in
> drivers/acpi/glue.c, and the above commit moves it to cmos_wake_setup()
> in this file.
>
> Now, with this patch, my understanding is that dev->platform_data is
> never set, thus we can remove the 'info' variable and the
>         if (info)
> check above.

There are other users of this driver which can be found by grepping
for cmos_rtc_board_info.

They create platform device objects with platform_data set which are
then bound to by this driver.