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authorTim Harvey <tharvey@gateworks.com>2016-04-01 08:16:43 -0700
committerWim Van Sebroeck <wim@iguana.be>2016-05-14 09:36:38 +0200
commitbc677ff42e81bbf78308a7b66cf7b63b0f5c26b0 (patch)
treedcef2c5380ca309e77a7f5a35fc0b16f0ab48415 /Documentation/devicetree/bindings/watchdog
parentebbf677a3fb54fda56c58fc985c4617c215da6a0 (diff)
watchdog: imx2_wdt: add external reset support via dt prop
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 'fsl,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: Fabio Estevam <festevam@gmail.com> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Stefan Roese <sr@denx.de> Cc: Iain Paton <ipaton0@gmail.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Tim Harvey <tharvey@gateworks.com> Reviewed-by: Lucas Stach <l.stach@pengutronix.de> Acked-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Akshay Bhat <akshay.bhat@timesys.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'Documentation/devicetree/bindings/watchdog')
-rw-r--r--Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt4
1 files changed, 3 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
index 8dab6fd024aa..107280ef0025 100644
--- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
@@ -5,10 +5,12 @@ Required properties:
- reg : Should contain WDT registers location and length
- interrupts : Should contain WDT interrupt
-Optional property:
+Optional 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.
+- fsl,ext-reset-output: If present the watchdog device is configured to
+ assert its external reset (WDOG_B) instead of issuing a software reset.
Examples: