linux-kernel - Re: [PATCH 2/4] MFD: intel

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Message-ID: <YN2vwT+7sVRvz8iS@dell>
Date:   Thu, 1 Jul 2021 13:06:25 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        "david.e.box@...ux.intel.com" <david.e.box@...ux.intel.com>,
        "mgross@...ux.intel.com" <mgross@...ux.intel.com>,
        "bhelgaas@...gle.com" <bhelgaas@...gle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [PATCH 2/4] MFD: intel_pmt: Remove OOBMSM device

On Thu, 01 Jul 2021, Andy Shevchenko wrote:

> On Thursday, July 1, 2021, Lee Jones <lee.jones@...aro.org> wrote:
> 
> > On Thu, 01 Jul 2021, Hans de Goede wrote:
> >
> > > Hi,
> > >
> > > On 6/30/21 11:11 PM, David E. Box wrote:
> > > > On Wed, 2021-06-30 at 11:15 +0100, Lee Jones wrote:
> > > >> On Thu, 17 Jun 2021, David E. Box wrote:
> > > >>
> > > >>> Unlike the other devices in intel_pmt, the Out of Band Management
> > > >>> Services
> > > >>> Module (OOBMSM) is actually not a PMT dedicated device. It can also
> > > >>> be used
> > > >>> to describe non-PMT capabilities. Like PMT, these capabilities are
> > > >>> also
> > > >>> enumerated using PCIe Vendor Specific registers in config space. In
> > > >>> order
> > > >>> to better support these devices without the confusion of a
> > > >>> dependency on
> > > >>> MFD_INTEL_PMT, remove the OOBMSM device from intel_pmt so that it
> > > >>> can be
> > > >>> later placed in its own driver. Since much of the same code will be
> > > >>> used by
> > > >>> intel_pmt and the new driver, create a new file with symbols to be
> > > >>> used by
> > > >>> both.
> > > >>>
> > > >>> While performing this split we need to also handle the creation of
> > > >>> platform
> > > >>> devices for the non-PMT capabilities. Currently PMT devices are
> > > >>> named by
> > > >>> their capability (e.g. pmt_telemetry). Instead, generically name
> > > >>> them by
> > > >>> their capability ID (e.g. intel_extnd_cap_2). This allows the IDs
> > > >>> to be
> > > >>> created automatically.  However, to ensure that unsupported devices
> > > >>> aren't
> > > >>> created, use an allow list to specify supported capabilities.
> > > >>>
> > > >>> Signed-off-by: David E. Box <david.e.box@...ux.intel.com>
> > > >>> ---
> > > >>>  MAINTAINERS                                |   1 +
> > > >>>  drivers/mfd/Kconfig                        |   4 +
> > > >>>  drivers/mfd/Makefile                       |   1 +
> > > >>>  drivers/mfd/intel_extended_caps.c          | 208
> > > >>> +++++++++++++++++++++
> > > >>
> > > >> Please consider moving this <whatever this is> out to either
> > > >> drivers/pci or drivers/platform/x86.
> > > >
> > > > None of the cell drivers are in MFD, only the PCI drivers from which
> > > > the cells are created. I understood that these should be in MFD. But
> > > > moving it to drivers/platform/x86 would be fine with me. That keeps the
> > > > code together in the same subsystem. Comment from Hans or Andy?
> > >
> > > I'm fine with moving everything to drivers/platform/x86, but AFAIK
> > > usually the actual code which has the MFD cells and creates the
> > > child devices usually lives under drivers/mfd
> >
> > Correct.  It must.
> 
> It’s definitely not the first time you are talking about, but it may be the
> first time I asked why it’s not enforced overall. Last time I have checked
> it was like 5-7 MFD uses outside the MFD folder. Are you going to fix that?

Because I can't NACK patches that weren't sent to me. :)

I'll probably look into 'fixing' it when I get some free time.

> > No MFD API users outside of drivers/mfd please.

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