From: Jonathan Cameron <jic23@kernel.org>
To: Dipen Patel <dipenp@nvidia.com>
Cc: <thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<linux-kernel@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-gpio@vger.kernel.org>, <linus.walleij@linaro.org>,
<bgolaszewski@baylibre.com>, <warthog618@gmail.com>,
<devicetree@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<robh+dt@kernel.org>
Subject: Re: [RFC 02/11] drivers: Add HTE subsystem
Date: Sun, 26 Sep 2021 16:42:42 +0100 [thread overview]
Message-ID: <20210926164242.7447c0e2@jic23-huawei> (raw)
In-Reply-To: <91744e4f-b1b8-399a-b521-aba0215a5dc4@nvidia.com>
On Mon, 13 Sep 2021 22:43:02 -0700
Dipen Patel <dipenp@nvidia.com> wrote:
> Hi Jonathan,
>
> I got some time to implement RFC version 2 while doing so I have a follow up comment
>
> inline regarding clock source comment of yours.
>
> Best Regards,
>
> Dipen Patel
>
...
> >>>> +/**
> >>>> + * struct hte_clk_info - Clock source info that HTE provider uses.
> >>>> + * The provider uses hardware clock as a source to timestamp real time. This
> >>>> + * structure presents the clock information to consumers.
> >>>> + *
> >>>> + * @hz: Clock rate in HZ, for example 1KHz clock = 1000.
> >>>> + * @type: Clock type. CLOCK_* types.
> >>> So this is something we got a it wrong in IIO. It's much better to define
> >>> a subset of clocks that can be potentially used. There are some that make
> >>> absolutely no sense and consumers really don't want to have to deal with them.
> >> Is there anything I have to change here?
> > Yes - specify which clocks would make sense. You might not need to explicitly
> > allow only those, but that might also be worthwhile. Otherwise, the chances are
> > you'll end up with a bunch of special purpose code in consumers on the basis
> > they might get CLOCK_TAI or similar and have to deal with it.
> > As for exactly which clocks do make sense, that's one which may take some figuring
> > out. Probably REALTIME, MONOTONIC and BOOTTIME depending on whether you care
> > what happens when the time of the system gets adjusted, or whether it carries
> > on measuring time across suspend. Very application dependent but there are some
> > you can definitely rule out. Don't repeat my mistake of leaving it vague
> > (which incidentally was a follow up to picking a silly clock to use for timestamps
> > before we allowed it to be configured).
>
> I believe your comment is under assumption that providers have choice in selecting
>
> clock source to timestamp in turns clients have it as well. For now, the provider
>
> I have implemented has single clock source and hence I only implemented get_clock*
>
> hook that provider implement and client can retrieve that information. I guess I can
>
> always implement set_clock* hook as well for the future providers which support
>
> multiple clock sources. Please let me if I missed your point.
I'll be honest I can't really remember :( too many sleeps.
Sorry - if it is still relevant perhaps it'll come back to me on v2.
Thanks,
Jonathan
next prev parent reply other threads:[~2021-09-26 15:38 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 23:55 [RFC 00/11] Intro to Hardware timestamping engine Dipen Patel
2021-06-25 23:55 ` [RFC 01/11] Documentation: Add HTE subsystem guide Dipen Patel
2021-07-04 18:55 ` Jonathan Cameron
2021-07-27 23:44 ` Dipen Patel
2021-08-01 15:24 ` Jonathan Cameron
2021-06-25 23:55 ` [RFC 02/11] drivers: Add HTE subsystem Dipen Patel
2021-06-27 17:40 ` Randy Dunlap
2021-07-04 20:15 ` Jonathan Cameron
2021-07-04 20:45 ` Jonathan Cameron
2021-07-28 5:12 ` Dipen Patel
2021-08-01 16:48 ` Jonathan Cameron
2021-07-28 4:38 ` Dipen Patel
2021-08-01 16:13 ` Jonathan Cameron
2021-09-14 5:43 ` Dipen Patel
2021-09-26 15:42 ` Jonathan Cameron [this message]
2021-07-05 7:30 ` Greg KH
2021-07-28 0:34 ` Dipen Patel
2021-06-25 23:55 ` [RFC 03/11] hte: Add tegra194 HTE kernel provider Dipen Patel
2021-07-01 14:21 ` Kent Gibson
2021-07-28 23:59 ` Dipen Patel
2021-07-30 7:01 ` Dipen Patel
2021-07-31 15:43 ` Kent Gibson
2021-08-03 22:40 ` Dipen Patel
2021-08-03 23:02 ` Kent Gibson
2021-08-07 2:41 ` Dipen Patel
2021-08-07 3:07 ` Kent Gibson
2021-08-07 4:52 ` Dipen Patel
2021-08-07 4:51 ` Kent Gibson
2021-08-07 5:35 ` Dipen Patel
2021-08-07 5:42 ` Kent Gibson
2021-08-07 5:47 ` Dipen Patel
2021-07-04 20:27 ` Jonathan Cameron
2021-07-29 2:42 ` Dipen Patel
2021-07-08 23:33 ` Michał Mirosław
2021-07-29 2:43 ` Dipen Patel
2021-06-25 23:55 ` [RFC 04/11] dt-bindings: Add HTE bindings Dipen Patel
2021-06-27 10:56 ` Linus Walleij
2021-07-30 1:32 ` Dipen Patel
2021-07-01 14:02 ` Rob Herring
2021-07-30 1:56 ` Dipen Patel
2021-07-01 15:54 ` Rob Herring
2021-07-30 1:58 ` Dipen Patel
2021-06-25 23:55 ` [RFC 05/11] hte: Add Tegra194 IRQ HTE test driver Dipen Patel
2021-06-27 17:42 ` Randy Dunlap
2021-06-25 23:55 ` [RFC 06/11] gpiolib: Add HTE support Dipen Patel
2021-06-27 11:41 ` Linus Walleij
2021-07-01 14:24 ` Kent Gibson
2021-07-30 2:25 ` Dipen Patel
2021-07-31 5:13 ` Kent Gibson
2021-06-25 23:55 ` [RFC 07/11] gpio: tegra186: Add HTE in gpio-tegra186 driver Dipen Patel
2021-06-25 23:55 ` [RFC 08/11] gpiolib: cdev: Add hardware timestamp clock type Dipen Patel
2021-06-27 11:38 ` Linus Walleij
2021-06-27 11:49 ` Linus Walleij
2021-07-30 3:16 ` Dipen Patel
2021-07-01 14:24 ` Kent Gibson
2021-07-30 3:07 ` Dipen Patel
2021-07-31 6:05 ` Kent Gibson
2021-08-03 22:41 ` Dipen Patel
2021-08-03 22:38 ` Kent Gibson
2021-07-09 8:30 ` Jon Hunter
2021-07-30 2:33 ` Dipen Patel
2021-08-03 16:42 ` Jon Hunter
2021-08-03 22:51 ` Dipen Patel
2021-08-03 23:09 ` Kent Gibson
2021-06-25 23:55 ` [RFC 09/11] tools: gpio: Add new hardware " Dipen Patel
2021-06-27 11:36 ` Linus Walleij
2021-07-30 3:17 ` Dipen Patel
2021-07-31 6:16 ` Kent Gibson
2021-08-11 9:11 ` Linus Walleij
2021-06-25 23:55 ` [RFC 10/11] hte: Add tegra GPIO HTE test driver Dipen Patel
2021-06-27 17:43 ` Randy Dunlap
2021-06-25 23:55 ` [RFC 11/11] MAINTAINERS: Added HTE Subsystem Dipen Patel
2021-06-27 13:07 ` [RFC 00/11] Intro to Hardware timestamping engine Andy Shevchenko
2021-06-27 14:40 ` Linus Walleij
2021-06-28 12:02 ` Andy Shevchenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210926164242.7447c0e2@jic23-huawei \
--to=jic23@kernel.org \
--cc=bgolaszewski@baylibre.com \
--cc=devicetree@vger.kernel.org \
--cc=dipenp@nvidia.com \
--cc=jonathanh@nvidia.com \
--cc=linus.walleij@linaro.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=thierry.reding@gmail.com \
--cc=warthog618@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).