[PATCH 3/3] arm: dts: ti: omap: Prevent watchdog from being reset on kernel boot

[Diogo Ivo <diogo.ivo@bootlin.com>]

Currently the ti-sysc driver resets and idles the watchdog when it probes
its target-module node. In a system where the watchdog is being used to
detect a faulty boot this makes it impossible for the watchdog to do its
function, in an unexpected and time-consuming manner to debug.

Explicitly mark the watchdog node with ti,no-reset-on-init to prevent
the reset portion from happening. This allows the watchdog driver proper
to maintain the watchdog running.

Signed-off-by: Diogo Ivo <diogo.ivo@bootlin.com>
---
The ti,no-idle property is deliberately not added to minimize the
possibility of a regression on systems that were relying on the ti-sysc
driver disabling the watchdog and did not service it. With just
ti,no-reset-on-init we get a 3 second window for the watchdog driver to
probe and maintain the watchdog alive, otherwise the system will behave
almost in the same way as before. The only difference comes from introducing
the small 3 second window that could lead to a watchdog expiration on systems
where the watchdog was being stopped right next to its expiration, but
that risk is much smaller regression-wise than always keeping its boot
status. If this approach is deemed appropriate this patch should be
mimicked in other TI SoC's with this watchdog.
---
 arch/arm/boot/dts/ti/omap/omap4-l4.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/ti/omap/omap4-l4.dtsi b/arch/arm/boot/dts/ti/omap/omap4-l4.dtsi
index c1afc49f456c..eb0e10e51ba4 100644
--- a/arch/arm/boot/dts/ti/omap/omap4-l4.dtsi
+++ b/arch/arm/boot/dts/ti/omap/omap4-l4.dtsi
@@ -1126,6 +1126,7 @@ target-module@4000 {			/* 0x4a314000, ap 7 18.0 */
 					<SYSC_IDLE_SMART>,
 					<SYSC_IDLE_SMART_WKUP>;
 			ti,syss-mask = <1>;
+			ti,no-reset-on-init;
 			/* Domains (V, P, C): wakeup, wkup_pwrdm, l4_wkup_clkdm */
 			clocks = <&l4_wkup_clkctrl OMAP4_WD_TIMER2_CLKCTRL 0>;
 			clock-names = "fck";

-- 
2.55.0