linux_dsm_epyc7002/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt
Tim Harvey bc677ff42e 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>
2016-05-14 09:36:38 +02:00

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* Freescale i.MX Watchdog Timer (WDT) Controller
Required properties:
- compatible : Should be "fsl,<soc>-wdt"
- reg : Should contain WDT registers location and length
- interrupts : Should contain WDT interrupt
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:
wdt@73f98000 {
compatible = "fsl,imx51-wdt", "fsl,imx21-wdt";
reg = <0x73f98000 0x4000>;
interrupts = <58>;
big-endian;
};