Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver

[Lee Jones]

On Wed, 29 Apr 2020, Tim Harvey wrote:

> On Tue, Apr 28, 2020 at 11:33 PM Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> >
> > On Tue, 28 Apr 2020, Tim Harvey wrote:
> >
> > > On Tue, Apr 28, 2020 at 2:44 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> > > >
> > > <snip>
> > > > > +
> > > > > +static int gsc_probe(struct i2c_client *client)
> > > > > +{
> > > > > +     struct device *dev = &client->dev;
> > > > > +     struct gsc_dev *gsc;
> > > > > +     int ret;
> > > > > +     unsigned int reg;
> > > > > +
> > > > > +     gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
> > > > > +     if (!gsc)
> > > > > +             return -ENOMEM;
> > > > > +
> > > > > +     gsc->dev = &client->dev;
> > > > > +     gsc->i2c = client;
> > > > > +     i2c_set_clientdata(client, gsc);
> > > > > +
> > > > > +     gsc->bus.reg_write = gsc_regmap_regwrite;
> > > > > +     gsc->bus.reg_read = gsc_regmap_regread;
> > > >
> > > > Why do you need to store these in ddata?
> > >
> > > Lee,
> > >
> > > Thanks for the review!
> > >
> > > I need the remap_bus* for devm_regmap_init() in the hwmon sub-module driver:
> > >
> > > hwmon->regmap = devm_regmap_init(dev, &gsc->bus, gsc->i2c_hwmon,
> > > &gsc_hwmon_regmap_config);
> > >
> > > Is there something easier I'm missing?
> >
> > This is an odd setup.  I haven't seen one driver registering another
> > driver's Regmap call-backs before, related or otherwise.  Normally the
> > Regmap is setup (initialised) in the parent driver and child drivers
> > just make use of it.  Here it looks like you are registering 2
> > separate Regmaps, but using the same call-backs for both, which seems
> > wrong to me.
> >
> 
> Lee,
> 
> It is perhaps an odd setup. The hwmon sub-device is at a different i2c
> slave address than the other sub-devices. The same callbacks are used
> for reg read/write to take advantage of the retries due to the errata
> resulting in occasional NAK'd register reads.

Then I suggest putting them somewhere shared or exporting them.

Passing pointers to the via ddata sounds a bit batty.

-- 
Lee Jones [æçæ]
Linaro Services Technical Lead
Linaro.org â Open source software for ARM SoCs
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