linux-kernel - Re: [PATCH 2/3] pinctrl: cy8c95x0: Use regmap ranges

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Message-ID: <CALNFmy38aq915Oj7x4q27OWbiympDU=Vjo=7anTYx7w3E=F2UA@mail.gmail.com>
Date: Tue, 20 Aug 2024 10:30:04 +0200
From: Patrick Rudolph <patrick.rudolph@...ements.com>
To: Andy Shevchenko <andy@...ck.fi.intel.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, naresh.solanki@...ements.com, 
	andy.shevchenko@...il.com, broonie@...nel.org, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] pinctrl: cy8c95x0: Use regmap ranges

On Fri, Aug 9, 2024 at 2:13 PM Andy Shevchenko <andy@...ck.fi.intel.com> wrote:
>
> On Tue, May 21, 2024 at 05:25:58PM +0200, Patrick Rudolph wrote:
> > Instead of implementing a custom register paging mechanism in
> > the driver use the existing regmap ranges feature.
>
> ...
>
> > +#define MUXED_STRIDE         (CY8C95X0_DRV_HIZ - CY8C95X0_INTMASK)
>
> > +#define CY8C95X0_MUX_REGMAP_TO_OFFSET(x, p) \
> > +     (CY8C95X0_VIRTUAL + (x) - CY8C95X0_INTMASK + (p) * MUXED_STRIDE)
>
> > +static const struct regmap_range_cfg cy8c95x0_ranges[] = {
> > +     {
> > +             .range_min = CY8C95X0_VIRTUAL,
> > +             .range_max = 0,         /* Updated at runtime */
> > +             .selector_reg = CY8C95X0_PORTSEL,
> > +             .selector_mask = 0x07,
> > +             .selector_shift = 0x0,
> > +             .window_start = CY8C95X0_INTMASK,
> > +             .window_len = MUXED_STRIDE,
>
> Looking at this again, are you sure you have no off-by-one error in
> MUXED_STRIDE value?
You are right. I tried to save some memory here. Will send out a fix.

>
> Also a comment in the regmap core suggests that we may include selector
> in each of the window.
>
> With this, we probably should simply use PORTSEL as window start with a
> fixed window len of 16, having a few more (reserved) registers in the
> dump seems not a big deal to me, but it will be much easier to decipher
> a port number based on (virtual) offset.
>
That's true.

> Besides above, why virtual start is not well aligned? I would expect not
> 0x31, but 0x40 or alike. It might explain some bugs with cache you have
> seen.
>
I didn't find any rules on this, so I used the next free index.

> P.S. It might still be bugs in regmap core, if it is the case, they
> need to be addressed.
>
> > +     }
> >  };
>
> --
> With Best Regards,
> Andy Shevchenko
>
>