Re: hwmon driver with misc interface

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Sun, 2018-07-08 at 23:37 -0700, Guenter Roeck wrote:
> On 07/08/2018 11:04 PM, Benjamin Herrenschmidt wrote:
> 
> > > Another option would be to handle it through regmap; That nowadays
> > > supports custom accesses implemented in the parent driver (see regmap_read
> > > and regmap_write in struct regmap_config). The child driver gets the
> > > regmap pointer and uses the regmap API. I don't see that as messy.
> > 
> > That works for purely MMIO based things, this isn't though.
> > 
> 
> Sorry, I meant reg_read and reg_write callbacks in struct regmap_config.
> I don't think those callbacks are limited to mmio; I find many other
> access types by browsing through code providing those callbacks.
> 
> Sure, one could consider regmap to be another bloat, but I find it to
> be a quite convenient abstraction layer.

It has been for some things. We use it in some of our drivers.

In the specific case of OCC, it's a bit more complex, we need to send
potentially fairly large "commands" to the SBE via the sbefifo driver
and receive the corresponding response in a buffer, so we have an API
between the drivers, which works well.

Cheers,
Ben.