From: Guenter Roeck <linux@roeck-us.net>
To: Moritz Fischer <moritz.fischer.private@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Moritz Fischer <moritz.fischer@ettus.com>,
linux-watchdog@vger.kernel.org, wim@iguana.be,
a.zummo@towertech.it, alexandre.belloni@free-electrons.com,
rtc-linux@googlegroups.com, alex.williams@ni.com
Subject: Re: [PATCH 0/2] DS1374 Watchdog fixes
Date: Tue, 25 Apr 2017 09:17:43 -0700 [thread overview]
Message-ID: <20170425161743.GA8443@roeck-us.net> (raw)
In-Reply-To: <CAJYdmeP+XEBPpUECO1rWpRDs-RVihc_va970jtv6iau3OuWMWA@mail.gmail.com>
On Tue, Apr 25, 2017 at 07:55:28AM -0700, Moritz Fischer wrote:
> Hi Guenter,
>
> On Mon, Apr 24, 2017 at 10:03 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> > On 04/24/2017 03:05 PM, Moritz Fischer wrote:
>
> >> I'm very unhappy with the CONFIG_DRV_RTC_DS1374_WDT way of enabling
> >> the watchdog behavior and currently I'm investigating how to make
> >> that work via DT.
> >>
> >> Watchdog maintainers, do you have an idea on how to do that in a
> >> non breaking fashion?
> >>
> >
> > Depends on what you mean with "non breaking". Just using the normal mfd
> > mechanisms, ie define an mfd cell for each client driver, should work.
> > Do you see any problems with that ? Either case, that doesn't seem
> > to be a watchdog driver problem, or am I missing something ?
>
> Well so currently watchdog behavior is selected (out of the two options alarm,
> or watchdog) by enabling the configuration option mentioned above.
> If I change this over to use a dt-based approach like dallas,ds1374-mode = <2>;
> to select the behavior in the mfd for example, won't that break people that
> relied on the old behavior? If everyone involved is ok with that, I'm happy
> to just add it to the binding.
>
Sorry, I must be missing something. Looking into the driver code, my
understanding is that CONFIG_RTC_DRV_DS1374_WDT enables the watchdog in
addition to rtc functionality, not one or the other. Sure you would need
a different configuration option if you were to move the watchdog code into
drivers/watchdog, but other than that I don't really understand the problem.
What is the issue with, for example,
config DS1374_WDT
bool "Dallas/Maxim DS1374 watchdog timer"
depends on MFD_DS1374
help
If you say Y here you will get support for the
watchdog timer in the Dallas Semiconductor DS1374
real-time clock chips.
in drivers/watchdog/Kconfig, and the mfd driver instantiating it like
any other mfd client driver ?
Either case, limiting support to DT based systems seems to be the wrong
approach. There might be Intel platforms using this chip.
> > I don't really see the point of doing that if you plan to move the watchdog
> > part of the driver into the watchdog directory. We for sure won't accept a
> > watchdog driver that does not use the watchdog infrastructure.
>
> The idea was to fix what's broken currently (this patchset) and then refactor.
> But if you prefer I can do all in one go instead.
>
It just seemed a waste to me to change/fix a function which is going to
be removed in a subsequent patch (I seem to recall that there was a fix
to the ioctl function).
If/when you move the driver to drivers/watchdog, please make sure that
it doesn't use any instantiation related static variables (ie other than
module parameters).
> >
> > Regarding
> > + /* WHY? */
> > + ds1374->wdd.timeout = t;
> >
> > Assuming you mean why the driver has to set the timeout value - not every
> > watchdog hardware supports timeouts in multiples of 1 second. The driver
> > is expected to set the value to the real timeout, not to the timeout asked
> > for by the infrastructure.
>
> Yeah that branch is work in progress and needs cleanup. Leftover from testing,
> before I had understood why. Branch needs cleanup. It also doesn't really use
> regmap_update_bits etc.
>
Well, you did enhance the code to use regmap, which by itself is a significant
improvement ...
Thanks,
Guenter
next prev parent reply other threads:[~2017-04-25 16:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-24 22:05 [PATCH 0/2] DS1374 Watchdog fixes Moritz Fischer
2017-04-24 22:05 ` [PATCH 1/2] rtc: ds1374: wdt: Fix issue with timeout scaling from secs to wdt ticks Moritz Fischer
2017-05-04 12:47 ` Alexandre Belloni
2017-04-24 22:05 ` [PATCH 2/2] rtc: ds1374: wdt: Fix stop/start ioctl always returning -EINVAL Moritz Fischer
2017-05-04 12:47 ` Alexandre Belloni
2017-04-25 5:03 ` [PATCH 0/2] DS1374 Watchdog fixes Guenter Roeck
2017-04-25 14:55 ` Moritz Fischer
2017-04-25 16:17 ` Guenter Roeck [this message]
2017-04-25 16:32 ` Alexandre Belloni
2017-04-25 16:58 ` Guenter Roeck
2017-04-25 19:58 ` Moritz Fischer
2017-04-25 20:22 ` Guenter Roeck
2017-04-25 20:34 ` Moritz Fischer
2017-04-25 21:05 ` Guenter Roeck
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=20170425161743.GA8443@roeck-us.net \
--to=linux@roeck-us.net \
--cc=a.zummo@towertech.it \
--cc=alex.williams@ni.com \
--cc=alexandre.belloni@free-electrons.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=moritz.fischer.private@gmail.com \
--cc=moritz.fischer@ettus.com \
--cc=rtc-linux@googlegroups.com \
--cc=wim@iguana.be \
/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).