From mboxrd@z Thu Jan 1 00:00:00 1970 From: shawnguo@kernel.org (Shawn Guo) Date: Sun, 28 Jun 2015 23:07:42 +0800 Subject: [PATCH v2 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop In-Reply-To: <1433448960-9257-2-git-send-email-tharvey@gateworks.com> References: <1432853677-5150-1-git-send-email-tharvey@gateworks.com> <1433448960-9257-1-git-send-email-tharvey@gateworks.com> <1433448960-9257-2-git-send-email-tharvey@gateworks.com> Message-ID: <20150628150742.GF10332@tiger> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jun 04, 2015 at 01:15:59PM -0700, Tim Harvey wrote: > 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 > Signed-off-by: Tim Harvey > --- > v2: > - rename property to 'ext-reset-output' based on ML feedback > - simplify setting SRS bit if external-reset > - update comments and commit msg > > Signed-off-by: Tim Harvey > --- > .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ > drivers/watchdog/imx2_wdt.c | 17 +++++++++++++++-- > 2 files changed, 17 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: > - 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 > + external reset (WDOG_B) instead of issuing a software reset. This is a vendor specific binding property rather than generic one, so it should have a vendor prefix, i.e. "fsl,". Other than that, Acked-by: Shawn Guo