From: Guenter Roeck <linux@roeck-us.net>
To: Tim Harvey <tharvey@gateworks.com>
Cc: Akshay Bhat <akshay.bhat@timesys.com>,
linux-watchdog@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Wim Van Sebroeck <wim@iguana.be>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <kernel@pengutronix.de>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
justin.waters@timesys.com, Lucas Stach <l.stach@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>, Stefan Roese <sr@denx.de>
Subject: Re: [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop
Date: Fri, 6 Nov 2015 14:02:49 -0800 [thread overview]
Message-ID: <20151106220249.GA19791@roeck-us.net> (raw)
In-Reply-To: <CAJ+vNU2fSxRJ7YvxOfNzoEoiKgzv-dHj=+eksKxH48ekHiUw2Q@mail.gmail.com>
On Fri, Nov 06, 2015 at 11:53:42AM -0800, Tim Harvey wrote:
> On Thu, Nov 5, 2015 at 2:23 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> > On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote:
> >> From: Tim Harvey <tharvey@gateworks.com>
> >>
> >> The IMX6 watchdog supports assertion of a signal (WDOG_B) which
> >> can be pinmux'd to an external pin. This is typically used for boards that
> >> have PMIC's in control of the IMX6 power rails. In fact, failure to use
> >> such an external reset on boards with external PMIC's can result in various
> >> hangs due to the IMX6 not being fully reset [1] as well as the board failing
> >> to reset because its PMIC has not been reset to provide adequate voltage for
> >> the CPU when coming out of reset at 800Mhz.
> >>
> >> This uses a new device-tree property 'ext-reset-output' to indicate the
> >> board has such a reset and to cause the watchdog to be configured to assert
> >> WDOG_B instead of an internal reset both on a watchdog timeout and in
> >> system_restart.
> >>
> >> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html
> >>
> >> Cc: Lucas Stach <l.stach@pengutronix.de>
> >> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
> >> ---
> >> .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++
> >> drivers/watchdog/imx2_wdt.c | 20 ++++++++++++++++++--
> >> 2 files changed, 20 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
> >> index 8dab6fd..9b89b3a 100644
> >> --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
> >> +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
> >> @@ -9,6 +9,8 @@ Optional property:
> >
> > properties ?
> >
> >> - big-endian: If present the watchdog device's registers are implemented
> >> in big endian mode, otherwise in native mode(same with CPU), for more
> >> detail please see: Documentation/devicetree/bindings/regmap/regmap.txt.
> >> +- ext-reset-output: If present the watchdog device is configured to assert its
> >
> > Should that have a vendor prefix ? Also, not sure if "-output"
> > has any real value in the property name. "fsl,external-reset", maybe ?
>
> Hi Guenter,
>
> I don't see why a vendor prefix is necessary - its a feature of the
> IMX6 watchdog supported by this driver to be able to trigger an
> internal chip-level reset and/or an external signal that can be hooked
> to additional hardware.
>
Sounded like vendor specific to me, but then I am not a devicetree maintainer,
so I am not an authority on the subject.
> I started with ext-reset, but it was suggested
> (http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/347437.html)
> to also make it clear that this is an 'output' and not a reset input.
>
No problem, as long as you get an Ack from a devicetree maintainer.
Guenter
next prev parent reply other threads:[~2015-11-06 22:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 21:19 [PATCH v4 0/2] imx6: Implement external watchdog reset Akshay Bhat
2015-11-05 21:19 ` [PATCH v4 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Akshay Bhat
2015-11-05 22:23 ` Guenter Roeck
2015-11-06 19:53 ` Tim Harvey
2015-11-06 22:02 ` Guenter Roeck [this message]
2015-12-02 19:11 ` Akshay Bhat
2015-12-02 20:54 ` Tim Harvey
2015-12-17 15:02 ` Tim Harvey
2015-12-17 15:32 ` Guenter Roeck
2015-12-28 16:29 ` Wim Van Sebroeck
2016-01-28 20:28 ` Akshay Bhat
2016-02-28 13:56 ` Fabio Estevam
2016-03-28 20:19 ` Akshay Bhat
2016-03-30 1:22 ` Shawn Guo
2016-03-30 21:09 ` Guenter Roeck
2016-03-31 1:57 ` Shawn Guo
2016-03-31 18:01 ` Tim Harvey
2016-04-01 1:39 ` Shawn Guo
2015-11-05 21:19 ` [PATCH v4 2/2] ARM: dts: ventana: Add ext-reset support Akshay Bhat
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