SLEEP mode

rk3036 : no sleep support in current code source
rk3288 : Core power closed, DDR Retention
rk3399 : Core power closed,Logic power closed,DDR Retention

Linux

Command to enter suspend:

echo mem > /sys/power/state

You could bind this to a input key, it depend on Display Manager or Service manager.

DDR Retention

To disbale DDR Retention,

echo 0 >  /sys/module/pm/parameters/deep_sleep

wakeup

key (support wake from deep sleep):

gpio-keys {
        compatible = "gpio-keys";
        #address-cells = <1>;
        #size-cells = <0>;
        autorepeat;

        pinctrl-names = "default";
        pinctrl-0 = <&pwrbtn>;

        button@0 {
            gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
            linux,code = <116>;
            label = "GPIO Key Power";
            linux,input-type = <1>;
            gpio-key,wakeup = <1>;
            debounce-interval = <100>;
        };
    };