Hi Geert,
> Subject: Re: [PATCH v2 4/5] mfd: Add Renesas PMIC RAA215300 RTC driver
>
> Hi Biju,
>
> On Tue, May 9, 2023 at 9:35 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > Subject: Re: [PATCH v2 4/5] mfd: Add Renesas PMIC RAA215300 RTC
> > > driver On Tue, May 9, 2023 at 9:06 AM Biju Das
> <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > > Subject: [PATCH v2 4/5] mfd: Add Renesas PMIC RAA215300 RTC
> > > > > driver
> > > > >
> > > > > Currently, it is not possible to instantiate the i2c client
> > > > > driver using MFD cell as it is not a platform driver. Add
> > > > > support for Renesas PMIC
> > > > > RAA215300 RTC platform driver, so that it can be instantiated by
> > > > > MFD
> > > API.
> > > > > The rtc device is created by using i2c_new_ancillary_device()
> > > > > and it register as the rtc device by the helper function
> > > > > provided by
> > > > > rtc-isl2108 driver.
> > > >
> > > > Not sure this platform driver has to be placed in RTC subsystem
> > > > rather than MFD subsystem as PMIC MFD driver, can instantiate it using
> MFD cell??
> > >
> > > Can't you just instantiate the i2c ancillary device from the PMIC
> > > driver, and drop the new mfd and platform rtc drivers?
> >
> > Yes, it is possible.
> >
> > The only reason MFD is used for future expansion like adding support
> > for
> >
> > 1) battery charger
> > Or
> > 2) regulator
>
> I'd just start with a skeleton regulator ("PMIC") driver...
>
> > In that case, we can share regmap to sub devices. But these drivers are
> not currently planned.
> >
> > Apart from that,
> >
> > 1) It avoids subsystem dependencies, ie, PMIC driver directly calling rtc
> driver
> > for registering RTC device.
>
> You mean the direct call into raa215300_rtc_probe_helper()?
Yes, indeed.
> I think that can be solved by enhancing i2c_new_ancillary_device() to take a
> proper device name, instead of using "dummy"?
Geert, Wolfram,
Any pointers for instantiating i2c_client device(for eg: rtc_isl1208.c)
by enhancing i2c_new_ancillary_device() api?
Apart for this, since a single compatible(the pmic one) is used,
In rtc device probe, How do we identify this PMIC RTC device and use the "TYPE_ISL1208" config
in RTC driver, once we instantiate RTC device?
>
> > 2) I guess, the current split will also give some modular design.
> > We have a control to enable or disable the driver.
> > ie, Enable the driver PMIC with RTC enabled and
> > disable the driver PMIC with RTC not enabled(ie, XIN/XOUT grounded) in
> the system design
> > by controlling the config "PMIC_RAA215300_RTC".
>
> You already have CONFIG_RTC_DRV_ISL1208, and look at "renesas,rtc-enabled"
> before activating the RTC?
I agree. this will take care. I just added this CONFIG, so that we can have
Built-in PMIC driver and RTC module driver??
Cheers,
Biju
>
> > These are the reasons for creating MFD driver and platform device.
> >
> > I may be totally wrong. Please correct me if that is the case.
