Hi Andy,
On Sat, Jun 11, 2022 at 12:34:59PM +0200, Andy Shevchenko wrote:
> On Fri, Jun 10, 2022 at 7:57 PM Colin Foster
> <colin.foster@xxxxxxxxxxxxxxxx> wrote:
> >
> > There are a few Ocelot chips that contain the logic for this bus, but are
> > controlled externally. Specifically the VSC7511, 7512, 7513, and 7514. In
> > the externally controlled configurations these registers are not
> > memory-mapped.
> >
> > Add support for these non-memory-mapped configurations.
>
> ...
>
> > + ocelot_platform_init_regmap_from_resource(pdev, 0, &mii_regmap, NULL,
> > + &mscc_miim_regmap_config);
>
> This is a bit non-standard, why not to follow the previously used API
> design, i.e.
>
> mii_regmap.map = ...
>
> ?
I see your point. It looks like there's no reason to pass in &mii_regmap
and it can just be returned.
>
> ...
>
> > + ocelot_platform_init_regmap_from_resource(pdev, 1, &phy_regmap, &res,
> > + &mscc_miim_phy_regmap_config);
>
> Ditto.
>
> Also here is the question how '_from_' is aligned with '&res'. If
> it's _from_ a resource then the resource is already a pointer.
Yes, this is probably worth a second look. During v8 you noted that I
was repeating a lot of the same logic across several files, so I created
ocelot_platform_init_regmap_from_resource.
The "gotcha" is while most of those scenarios have a required resource,
the phy_regmap is optional - so a scenario where the resource doesn't
exist could be considered valid.
Would it make sense to make the init_regmap_from_resource function
return ERR_PTR(-ENOENT) if regs doesn't exist? That would clean up the
API quite a bit:
phy_regmap = ocelot_platform_init_regmap_from_resource(pdev, 1,
&map_config);
if (IS_ERR(phy_regmap) && phy_regmap != -ENOENT) {
dev_err(); ...
}
It looks like none of the two functions that would get returned
otherwise (devm_regmap_init or devm_regmap_init_mmio) would return that
value...
>
> ...
>
> > if (res) {
> > - phy_regs = devm_ioremap_resource(dev, res);
> > - if (IS_ERR(phy_regs)) {
> > - dev_err(dev, "Unable to map internal phy registers\n");
> > - return PTR_ERR(phy_regs);
> > - }
> > -
> > - phy_regmap = devm_regmap_init_mmio(dev, phy_regs,
> > - &mscc_miim_phy_regmap_config);
> > if (IS_ERR(phy_regmap)) {
> > dev_err(dev, "Unable to create phy register regmap\n");
> > return PTR_ERR(phy_regmap);
> > }
>
> This looks weird. You check an error here instead of the API you
> called. It's a weird design, the rationale of which is doubtful and
> has to be at least explained.
I agree. With the changes I'm suggesting above this block of code would
become:
if (IS_ERR(phy_regmap)) {
if (phy_regmap == -ENOENT) {
phy_regmap = NULL;
} else {
dev_err(dev, "...");
return PTR_ERR(phy_regmap);
}
}
That seems easier to follow than the if(res) block...
Thanks for the feedback!
>
> > + } else {
> > + phy_regmap = NULL;
> > }
>
> --
> With Best Regards,
> Andy Shevchenko
