ARM: dts: rockchip: Mark that the rk3288 timer might stop in suspend

This is similar to commit e6186820a745 ("arm64: dts: rockchip: Arch
counter doesn't tick in system suspend").  Specifically on the rk3288
it can be seen that the timer stops ticking in suspend if we end up
running through the "osc_disable" path in rk3288_slp_mode_set().  In
that path the 24 MHz clock will turn off and the timer stops.

To test this, I ran this on a Chrome OS filesystem:
  before=$(date); \
  suspend_stress_test -c1 --suspend_min=30 --suspend_max=31; \
  echo ${before}; date

...and I found that unless I plug in a device that requests USB wakeup
to be active that the two calls to "date" would show that fewer than
30 seconds passed.

NOTE: deep suspend (where the 24 MHz clock gets disabled) isn't
supported yet on upstream Linux so this was tested on a downstream
kernel.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index 171231a..1e5260b 100644 (file)
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -231,6 +231,7 @@
                             <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>,
                             <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
                clock-frequency = <24000000>;
+               arm,no-tick-in-suspend;
        };
 
        timer: timer@ff810000 {