[RFC v8 net-next 08/16] mfd: ocelot: add support for the vsc7512 chip via spi

[Vladimir Oltean]

On Mon, May 09, 2022 at 04:49:22PM -0700, Colin Foster wrote:
> > > +struct regmap *ocelot_init_regmap_from_resource(struct device *child,
> > > +						const struct resource *res)
> > > +{
> > > +	struct device *dev = child->parent;
> > > +
> > > +	return ocelot_spi_devm_init_regmap(dev, child, res);
> > 
> > So much for being bus-agnostic :-/
> > Maybe get the struct ocelot_ddata and call ocelot_spi_devm_init_regmap()
> > via a function pointer which is populated by ocelot-spi.c? If you do
> > that don't forget to clean up drivers/mfd/ocelot.h of SPI specific stuff.
> 
> That was my initial design. "core" was calling into "spi" exclusively
> via function pointers.
> 
> The request was "Please find a clearer way to do this without function
> pointers"
> 
> https://lore.kernel.org/netdev/Ydwju35sN9QJqJ%2FP@google.com/

Yeah, I'm not sure what Lee was looking for, either. In any case I agree
with the comment that you aren't configuring a bus. In this context it
seems more appropriate to call this function pointer "init_regmap", with
different implementations per transport.

Or alternatively you could leave the "core"/"spi" pseudo-separation up
to the next person who needs to add support for some other register I/O
method.