linux-kernel - Re: [PATCH v3] mfd: syscon: Add Spreadtrum physical regmap bus support

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Date:   Tue, 28 Apr 2020 08:14:47 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Baolin Wang <baolin.wang7@...il.com>
Cc:     Arnd Bergmann <arnd@...db.de>, Mark Brown <broonie@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] mfd: syscon: Add Spreadtrum physical regmap bus
 support

On Tue, 28 Apr 2020, Baolin Wang wrote:

> On Mon, Apr 27, 2020 at 5:05 PM Lee Jones <lee.jones@...aro.org> wrote:
> >
> > On Mon, 27 Apr 2020, Baolin Wang wrote:
> >
> > > Hi Arnd and Lee,
> > >
> > > On Tue, Apr 21, 2020 at 10:13 PM Baolin Wang <baolin.wang7@...il.com> wrote:
> > > >
> > > > Some platforms such as Spreadtrum platform, define a special method to
> > > > update bits of the registers instead of read-modify-write, which means
> > > > we should use a physical regmap bus to define the reg_update_bits()
> > > > operation instead of the MMIO regmap bus. Thus we can register a new
> > > > physical regmap bus into syscon core to support this.
> > > >
> > > > Signed-off-by: Baolin Wang <baolin.wang7@...il.com>
> > >
> > > Do you have any comments for this patch? Thanks.
> >
> > Yes.  I'm not accepting it, sorry.
> >
> > I'd rather you duplicate the things you need from of_syscon_register()
> > in your own driver than taint this one.
> 
> Thanks for your comments and I can understand your concern. But we
> still want to use the standard syscon APIs in syscon.c, which means we
> still need insert an callback or registration or other similar methods
> to support vendor specific regmap bus. Otherwise we should invent some
> similar syscon APIs in our vendor syscon driver, like
> sprd_syscon_regmap_lookup_by_phandle/sprd_syscon_regmap_lookup_by_compatible.

So long as the generic driver stays generic.  Providing a registration
function sounds cleaner than tainting the code with vendor specifics.

> Arnd, what do you think? Thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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