Re: [PATCH v2 2/3] mfd: lp873x: Add lp873x PMIC support

[Keerthy]

On Tuesday 17 May 2016 01:34 PM, Keerthy wrote:
> On Tuesday 17 May 2016 01:31 PM, Lee Jones wrote:
> > On Fri, 13 May 2016, Keerthy wrote:
> > > On Thursday 12 May 2016 06:48 PM, Lee Jones wrote:
> > > > On Tue, 10 May 2016, Keerthy wrote:
> > > >
> > > > > The LP873X chip is a power management IC for Portable Navigation
> > > > > Systems
> > > > >      and Tablet Computing devices. It contains the following
> > > > > components:
> > > > >
> > > > >       - Regulators.
> > > > >       - Configurable General Purpose Output Signals(GPO).
> > > > >
> > > > > PMIC interacts with the main processor through i2c. PMIC has
> > > > > couple of LDOs(Linear Regulators), couple of BUCKs (Step-Down DC-DC
> > > > > Converter Cores) and GPOs(General Purpose Output Signals). At this
> > > > > time only the regulator functionality is made available.
> > > > >
> > > > > Signed-off-by: Keerthy <j-keerthy@xxxxxx>
> > > > > ---
> > > > >
> > > > > Changes in v2:
> > > > >
> > > > >    * Used mfd_add_devices instead of of_pltaform_populate.
> > > >
> > > > Didn't see this conversation, but of_platform_populate () is usually
> > > > okay?
> > >
> > > https://lkml.org/lkml/2016/5/6/244.
> >
> > Did Mark tell you why you shouldn't be using it?
>
> "You shouldn't be using that, you should just have a table of subdevices
> in the MFD"
>
> I inferred not to use of_platform_populate and make use of
> mfd_add_devices instead.
>
> Please correct me if am wrong.

To answer why, Here is what Mark told:

https://lkml.org/lkml/2016/5/6/7


> > > > >   drivers/mfd/Kconfig        |  15 +++
> > > > >   drivers/mfd/Makefile       |   2 +
> > > > >   drivers/mfd/lp873x.c       |  98 +++++++++++++++++
> > > > >   include/linux/mfd/lp873x.h | 265
> > > > > +++++++++++++++++++++++++++++++++++++++++++++
> > > > >   4 files changed, 380 insertions(+)
> > > > >   create mode 100644 drivers/mfd/lp873x.c
> > > > >   create mode 100644 include/linux/mfd/lp873x.h
> >
> > [...]
> >
> > > > > +/**
> > > > > + * struct lp873x - state holder for the lp873x driver
> > > > > + * Device data may be used to access the LP873X chip
> > > > > + */
> > > > > +struct lp873x {
> > > > > +    struct device *dev;
> > > > > +    unsigned long id;
> > > > > +    u8 rev;
> > > > > +    struct mutex lp873_lock;    /* lock guarding the data
> > > > > structure */
> > > > > +    struct regmap *regmap;
> > > >
> > > > Are all of these used in >1 driver?
> > >
> > > Apart from id and rev all are used.
> >
> > Then why are id and rev in there?