From: Kent Gibson <warthog618@gmail.com>
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, devicetree@vger.kernel.org,
linux-doc@vger.kernel.org, robh+dt@kernel.org
Subject: Re: [RFC 03/11] hte: Add tegra194 HTE kernel provider
Date: Sat, 7 Aug 2021 13:42:12 +0800 [thread overview]
Message-ID: <20210807054212.GA15085@sol> (raw)
In-Reply-To: <7f6a2591-c264-e005-18ae-242320d4a22e@nvidia.com>
On Fri, Aug 06, 2021 at 10:35:10PM -0700, Dipen Patel wrote:
>
> On 8/6/21 9:51 PM, Kent Gibson wrote:
> > On Fri, Aug 06, 2021 at 09:52:54PM -0700, Dipen Patel wrote:
> >> On 8/6/21 8:07 PM, Kent Gibson wrote:
> >>> On Fri, Aug 06, 2021 at 07:41:09PM -0700, Dipen Patel wrote:
> >>>> On 7/31/21 8:43 AM, Kent Gibson wrote:
> >>>>> On Wed, Jul 28, 2021 at 04:59:08PM -0700, Dipen Patel wrote:
> >>>>>> Thanks Kent for the review comment. My responses inline.
> >>>>>>
> > <snip>
> >
> >>>> 2. Does hte handler solution create race between two handlers? i.e. edge_irq_handler and
> >>>>
> >>>> hte_handler, for the worst case scenario as below?
> >>>>
> >>> No. If hardware timestamp is selected then no irq is requested from the
> >>> irq subsystem for that line - only from the hte subsystem instead.
> >>> So there will be no edge_irq_handler call for that line, so no possible race.
> >> That is not possible for certain providers, for example the one I am dealing
> >>
> >> with which requires GPIO line to be requested as input and IRQ needs to
> >>
> >> be enabled on them.
> >>
> > So, for your hte subsystem to work, the consumer has to also request
> > a line from the irq subsystem?
>
> Yes
>
> > That makes sense to you?
> Its not me, its peculiarity of the hardware that I am dealing with.
My point is that the peculiarities of the hardware should be hidden from
the hte API user, especially if it is only necessary for some hardware.
> > Have hte do that, rather than the consumer.
>
> Sure, for cdev it would mean to duplicate (most of) the edge* or line_create
>
> code in HTE.
And your current way every other hte user will have to duplicate the
gpiolib-cdev code....
> For such hardware, my initial doubt remains the same about
>
> the worst case scenario between two handlers, but perhaps that's
>
> implementation details for hte to handle.
>
Indeed.
Cheers,
Kent.
> >
> > And another reason it makes sense to integrate this with irq...
>
> Alright, will explore this route as well. I remember both Thierry[1] and
>
> Marc[2] raised some doubts (time to revive that discussion).
>
>
> [1]: https://lore.kernel.org/lkml/YFm9r%2FtFkzVlYDEp@orome.fritz.box/
>
> [2]: https://lore.kernel.org/lkml/87h7l1k9yi.wl-maz@kernel.org/
>
> >
> > Cheers,
> > Kent.
next prev parent reply other threads:[~2021-08-07 5:42 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
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 [this message]
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
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