From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>,
Greg KH <gregkh@linuxfoundation.org>,
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>,
lee.jones@linaro.org
Subject: Re: [resend/standalone PATCH v4] Add auxiliary bus support
Date: Fri, 18 Dec 2020 22:16:58 +0100 [thread overview]
Message-ID: <20201218211658.GH3143569@piout.net> (raw)
In-Reply-To: <20201218205856.GZ552508@nvidia.com>
On 18/12/2020 16:58:56-0400, Jason Gunthorpe wrote:
> On Fri, Dec 18, 2020 at 08:32:11PM +0000, Mark Brown wrote:
>
> > > So, I strongly suspect, MFD should create mfd devices on a MFD bus
> > > type.
> >
> > Historically people did try to create custom bus types, as I have
> > pointed out before there was then pushback that these were duplicating
> > the platform bus so everything uses platform bus.
>
> Yes, I vaugely remember..
>
> I don't know what to say, it seems Greg doesn't share this view of
> platform devices as a universal device.
>
> Reading between the lines, I suppose things would have been happier
> with some kind of inheritance scheme where platform device remained as
> only instantiated directly in board files, while drivers could bind to
> OF/DT/ACPI/FPGA/etc device instantiations with minimal duplication &
> boilerplate.
>
> And maybe that is exactly what we have today with platform devices,
> though the name is now unfortunate.
>
> > I can't tell the difference between what it's doing and what SOF is
> > doing, the code I've seen is just looking at the system it's running
> > on and registering a fixed set of client devices. It looks slightly
> > different because it's registering a device at a time with some wrapper
> > functions involved but that's what the code actually does.
>
> SOF's aux bus usage in general seems weird to me, but if you think
> it fits the mfd scheme of primarily describing HW to partition vs
> describing a SW API then maybe it should use mfd.
>
> The only problem with mfd as far as SOF is concerned was Greg was not
> happy when he saw PCI stuff in the MFD subsystem.
>
But then again, what about non-enumerable devices on the PCI device? I
feel this would exactly fit MFD. This is a collection of IPs that exist
as standalone but in this case are grouped in a single device.
Note that I then have another issue because the kernel doesn't support
irq controllers on PCI and this is exactly what my SoC has. But for now,
I can just duplicate the irqchip driver in the MFD driver.
> This whole thing started when Intel first proposed to directly create
> platform_device's in their ethernet driver and Greg had a quite strong
> NAK to that.
Let me point to drivers/net/ethernet/cadence/macb_pci.c which is a
fairly recent example. It does exactly that and I'm not sure you could
do it otherwise while still not having to duplicate most of macb_probe.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
next prev parent reply other threads:[~2020-12-18 21:18 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
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 [this message]
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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