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@xxxxxxxxxxxx> wrote: > > On Thu, Nov 05, 2015 at 04:19:21PM -0500, Akshay Bhat wrote: > >> From: Tim Harvey <tharvey@xxxxxxxxxxxxx> > >> > >> 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@xxxxxxxxxxxxxx> > >> Signed-off-by: Tim Harvey <tharvey@xxxxxxxxxxxxx> > >> --- > >> .../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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
