From: Arnd Bergmann <arnd@kernel.org>
To: Min Li <min.li.xe@renesas.com>
Cc: Derek Kiernan <derek.kiernan@xilinx.com>,
Dragan Cvetic <dragan.cvetic@xilinx.com>,
Arnd Bergmann <arnd@arndb.de>,
gregkh <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Networking <netdev@vger.kernel.org>,
Richard Cochran <richardcochran@gmail.com>
Subject: Re: [PATCH net-next] misc: Add Renesas Synchronization Management Unit (SMU) support
Date: Tue, 16 Feb 2021 21:44:45 +0100 [thread overview]
Message-ID: <CAK8P3a2TeeLfsTNkZPnC3YowdOS=bFM5yYj58crP6F5U9Y_r-Q@mail.gmail.com> (raw)
In-Reply-To: <OSBPR01MB47732AFC03DA8A0DDF626706BA879@OSBPR01MB4773.jpnprd01.prod.outlook.com>
On Tue, Feb 16, 2021 at 6:10 PM Min Li <min.li.xe@renesas.com> wrote:
> > > If I come up with a new file and move all the abstraction code there,
> > > does that work?
> >
> > I think so, but it's more important to figure out a good user space interface
> > first. The ioctl interfaces should be written on a higher-level abstraction, to
> > ensure they can work with any hardware implementation and are not
> > specific to Renesas devices.
> >
> > Can you describe on an abstract level how a user would use the character
> > device, and what they achieve by that?
>
> This driver is meant to be used by Renesas PTP Clock Manager for
> Linux (pcm4l) software for Renesas device only.
>
> About how pcm4l uses the char device, pcm4l will open the device
> and do the supported ioctl cmds on the device, simple like that.
>
> At the same time, pcm4l will also open ptp hardware clock device,
> which is /dev/ptp[x], to do clock adjustments.
I can't help but think you are evading my question I asked. If there is no
specific action that this pcm4l tool needs to perform, then I'd think
we should better not provide any interface for it at all.
I also found a reference to only closed source software at
https://www.renesas.com/us/en/software-tool/ptp-clock-manager-linux
We don't add low-level interfaces to the kernel that are only
usable by closed-source software.
Once you are able to describe the requirements for what pcm4l
actually needs from the hardware, we can start discussing what
a high-level interface would look like that can be used to replace
the your current interface, in a way that would work across vendors
and with both pcm4l and open-source tools that do the same job.
Arnd
next prev parent reply other threads:[~2021-02-16 20:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 3:03 [PATCH net-next] misc: Add Renesas Synchronization Management Unit (SMU) support min.li.xe
2021-02-11 5:47 ` kernel test robot
2021-02-11 7:06 ` Greg KH
2021-02-11 12:54 ` Greg KH
2021-02-11 13:29 ` Arnd Bergmann
[not found] ` <OSBPR01MB47732017A97D5C911C4528F0BA8B9@OSBPR01MB4773.jpnprd01.prod.outlook.com>
2021-02-12 9:24 ` Arnd Bergmann
2021-02-12 16:16 ` Min Li
2021-02-12 19:50 ` Arnd Bergmann
2021-02-16 17:10 ` Min Li
2021-02-16 20:44 ` Arnd Bergmann [this message]
2021-02-16 22:14 ` Min Li
2021-02-17 15:56 ` Arnd Bergmann
[not found] ` <OSBPR01MB477394546AE3BC1F186FC0E9BA869@OSBPR01MB4773.jpnprd01.prod.outlook.com>
2021-02-17 21:30 ` Arnd Bergmann
2021-02-17 23:07 ` Jakub Kicinski
2021-02-18 3:28 ` Min Li
2021-02-18 10:50 ` Arnd Bergmann
2021-02-18 16:14 ` Min Li
2021-02-18 23:03 ` FW: " Min Li
2021-02-22 16:21 ` Min Li
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