From: Lee Jones <lee.jones@linaro.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>,
Greg KH <gregkh@linuxfoundation.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Dan Williams <dan.j.williams@intel.com>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
alsa-devel@alsa-project.org, Kiran Patil <kiran.patil@intel.com>,
linux-rdma <linux-rdma@vger.kernel.org>,
Shiraz Saleem <shiraz.saleem@intel.com>,
Martin Habets <mhabets@solarflare.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
Fred Oh <fred.oh@linux.intel.com>,
Dave Ertman <david.m.ertman@intel.com>,
Jakub Kicinski <kuba@kernel.org>, Netdev <netdev@vger.kernel.org>,
Leon Romanovsky <leonro@nvidia.com>,
David Miller <davem@davemloft.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Parav Pandit <parav@mellanox.com>
Subject: Re: [resend/standalone PATCH v4] Add auxiliary bus support
Date: Fri, 18 Dec 2020 19:09:11 +0000 [thread overview]
Message-ID: <20201218190911.GT207743@dell> (raw)
In-Reply-To: <20201218184150.GY552508@nvidia.com>
On Fri, 18 Dec 2020, Jason Gunthorpe wrote:
> On Fri, Dec 18, 2020 at 06:03:10PM +0000, Mark Brown wrote:
> > On Fri, Dec 18, 2020 at 12:28:17PM -0400, Jason Gunthorpe wrote:
> > > On Fri, Dec 18, 2020 at 03:52:04PM +0000, Mark Brown wrote:
> > > > On Fri, Dec 18, 2020 at 10:08:54AM -0400, Jason Gunthorpe wrote:
> >
> > > > > I thought the recent LWN article summed it up nicely, auxillary bus is
> > > > > for gluing to subsystems together using a driver specific software API
> > > > > to connect to the HW, MFD is for splitting a physical HW into disjoint
> > > > > regions of HW.
> >
> > > > This conflicts with the statements from Greg about not using the
> > > > platform bus for things that aren't memory mapped or "direct firmware",
> > > > a large proportion of MFD subfunctions are neither at least in so far as
> > > > I can understand what direct firmware means.
> >
> > > I assume MFD will keep existing and it will somehow stop using
> > > platform device for the children it builds.
> >
> > If it's not supposed to use platform devices so I'm assuming that the
> > intention is that it should use aux devices, otherwise presumably it'd
> > be making some new clone of the platform bus but I've not seen anyone
> > suggesting this.
>
> I wouldn't assume that, I certainly don't want to see all the HW
> related items in platform_device cloned roughly into aux device.
>
> I've understood the bus type should be basically related to the thing
> that is creating the device. In a clean view platform code creates
> platform devices. DT should create DT devices, ACPI creates ACPI
> devices, PNP does pnp devices, etc
>
> So, I strongly suspect, MFD should create mfd devices on a MFD bus
> type.
>
> Alexandre's point is completely valid, and I think is the main
> challenge here, somehow avoiding duplication.
>
> If we were to look at it with some OOP viewpoint I'd say the generic
> HW resource related parts should be some shared superclass between
> 'struct device' and 'struct platform/pnp/pci/acpi/mfd/etc_device'.
You're confusing things here.
ACPI, DT and MFD are not busses. They are just methods to
describe/register devices which will operate on buses.
Busses include things like; I2C, SPI, PCI, USB and Platform (MMIO).
--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2020-12-18 19:10 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 0:54 [resend/standalone PATCH v4] Add auxiliary bus support Dan Williams
2020-12-03 15:06 ` Greg KH
2020-12-04 2:33 ` Jason Gunthorpe
2020-12-04 3:37 ` Dan Williams
2020-12-03 15:07 ` Greg KH
2020-12-03 15:55 ` Leon Romanovsky
2020-12-04 11:42 ` Greg KH
2020-12-04 11:43 ` [PATCH 1/3] driver core: auxiliary bus: move slab.h from include file Greg KH
2020-12-04 11:44 ` [PATCH 2/3] driver core: auxiliary bus: make remove function return void Greg KH
2020-12-04 11:44 ` [PATCH 3/3] driver core: auxiliary bus: minor coding style tweaks Greg KH
2020-12-04 11:48 ` Greg KH
2020-12-04 11:49 ` [PATCH v2 " Greg KH
2020-12-04 12:32 ` [resend/standalone PATCH v4] Add auxiliary bus support Leon Romanovsky
2020-12-04 12:43 ` Parav Pandit
2020-12-04 12:59 ` Greg KH
2020-12-04 17:10 ` Ranjani Sridharan
2020-12-05 9:02 ` Greg KH
2020-12-04 16:41 ` Dan Williams
2020-12-05 15:51 ` Greg KH
2020-12-17 21:19 ` Alexandre Belloni
2020-12-18 2:39 ` Dan Williams
2020-12-18 14:20 ` Mark Brown
2020-12-18 7:10 ` Greg KH
2020-12-18 13:17 ` Mark Brown
2020-12-18 13:46 ` Lee Jones
2020-12-18 14:08 ` Jason Gunthorpe
2020-12-18 15:52 ` Mark Brown
2020-12-18 16:28 ` Jason Gunthorpe
2020-12-18 17:15 ` Alexandre Belloni
2020-12-18 18:03 ` Mark Brown
2020-12-18 18:41 ` Jason Gunthorpe
2020-12-18 19:09 ` Lee Jones [this message]
2020-12-18 20:14 ` Jason Gunthorpe
2020-12-18 20:32 ` Mark Brown
2020-12-18 20:58 ` Jason Gunthorpe
2020-12-18 21:16 ` Alexandre Belloni
2020-12-18 22:36 ` Dan Williams
2020-12-18 23:36 ` Jason Gunthorpe
2020-12-19 0:22 ` Alexandre Belloni
2020-12-21 18:51 ` Mark Brown
2021-01-04 18:08 ` Jason Gunthorpe
2021-01-04 21:19 ` Mark Brown
2021-01-05 0:13 ` Jason Gunthorpe
2021-01-05 0:51 ` Dan Williams
2021-01-05 1:53 ` Jason Gunthorpe
2021-01-05 3:12 ` Dan Williams
2021-01-05 12:49 ` Jason Gunthorpe
2021-01-05 13:42 ` Mark Brown
2021-01-05 14:36 ` Jason Gunthorpe
2021-01-05 15:47 ` Mark Brown
2020-12-04 12:35 ` Greg KH
2020-12-04 12:54 ` Leon Romanovsky
2020-12-04 16:25 ` Jakub Kicinski
2020-12-04 17:57 ` Saeed Mahameed
2020-12-04 18:05 ` Ranjani Sridharan
2020-12-06 0:24 ` David Ahern
2020-12-06 0:32 ` Dan Williams
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