[U-Boot] [PATCH] regmap: Separate memory-based operations

[Alexey Brodkin]

Hi Simon,

On Fri, 2018-05-25 at 20:07 -0600, Simon Glass wrote:
> Hi Alexey,
> 
> On 25 May 2018 at 03:45, Alexey Brodkin <Alexey.Brodkin at synopsys.com> wrote:
> > Hi Simon,
> > 
> > On Thu, 2018-05-24 at 20:42 -0600, Simon Glass wrote:
> > > Hi Alexey,

[snip]

> > > When we want to use a particular I2C bus via regmap, we could bind the
> > > I2C -> regmap driver as a child of the I2C bus driver.
> > 
> > I guess that will require us to do corresponding changes in Device Tree
> > descriptions, right? And that will deviate those .dts-es from their kernel
> > counterparts [if they exist for a particular board].
> 
> Actually I don't think so. You can have a helper function that you
> call to bind the regmap to an I2C device, for example. That can be
> called from code, without needing any DT changes.

So this helper function will be regmap_init_i2c(), right?

> My objection is mostly to using function pointers to call what look
> like driver functions. The design of DM in U-Boot is supposed to
> support child drivers for exactly this purpose. So we should try to
> use it, unless we hit some terrible design flaw.

Ok that makes sense. As you proposed we'll have new UCLASS like
UCLASS_SIMPLE_REG and within that class we'll have drivers that access
registers via memory, i2c, spi etc... that's quite clear.

But what is not very obvious for me is that part about binding with
"master" devices. Could you please sketch something so I may get a better
picture?

-Alexey