Re: [PATCH v2 09/16] reset: starfive-jh7100: Add StarFive JH7100 reset driver

[Andy Shevchenko]

On Fri, Oct 22, 2021 at 5:25 PM Emil Renner Berthing <kernel@xxxxxxxx> wrote:
> On Fri, 22 Oct 2021 at 15:39, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote:
> > On Fri, Oct 22, 2021 at 4:35 PM Emil Renner Berthing <kernel@xxxxxxxx> wrote:
> > > On Fri, 22 Oct 2021 at 14:56, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote:
> > > > On Thu, Oct 21, 2021 at 8:43 PM Emil Renner Berthing <kernel@xxxxxxxx> wrote:

...

> > > > Why all these ugly % 32 against constants?
> > >
> > > Because the JH7100_RST_ values goes higher than 31. There is a
> > > BIT_MASK macro, but that does % BITS_PER_LONG and this is a 64bit
> > > machine.
> >
> > And? It's exactly what you have to use!
>
> So you want me to use an unsigned long array or DECLARE_BITMAP and
> juggle two different index and bit offsets?

What are the offsets of those status registers?
AFAICS they are sequential 4 32-bit registers.

So bitmap is exactly what is suitable here, you are right!
See gpio-xilinx and gpio-pca953x on how to use bitmaps in the GPIO drivers.

> Also is there a macro for handling that we'd then need 4 commas on
> 32bit COMPILE_TEST and 2 commas on 64bit?
> If you have some other way in mind you'll have to be a lot more explicit again.
>
> The point of the jh7100_reset_asserted array is that it exactly
> mirrors the values of the status registers when the lines are
> asserted. Maybe writing it like this would be more explicit:
>
> static const u32 jh7100_reset_asserted[4] = {
>         /* STATUS0 register */
>         BIT(JH7100_RST_U74 % 32) |
>         BIT(JH7100_RST_VP6_DRESET % 32) |
>         BIT(JH7100_RST_VP6_BRESET % 32),
>         /* STATUS1 register */
>         BIT(JH7100_RST_HIFI4_DRESET % 32) |
>         BIT(JH7100_RST_HIFI4_BRESET % 32),
>         /* STATUS2 register */
>         BIT(JH7100_RST_E24 % 32),
>         /* STATUS3 register */
>         0,
> };

--
With Best Regards,
Andy Shevchenko