1*4882a593Smuzhiyun* Amlogic Virtual RTC (VRTC) 2*4882a593Smuzhiyun 3*4882a593SmuzhiyunThis is a Linux interface to an RTC managed by firmware, hence it's 4*4882a593Smuzhiyunvirtual from a Linux perspective. The interface is 1 register where 5*4882a593Smuzhiyunan alarm time (in seconds) is to be written. 6*4882a593Smuzhiyun 7*4882a593SmuzhiyunRequired properties: 8*4882a593Smuzhiyun- compatible: should be "amlogic,meson-vrtc" 9*4882a593Smuzhiyun- reg: physical address for the alarm register 10*4882a593Smuzhiyun 11*4882a593SmuzhiyunThe alarm register is a simple scratch register shared between the 12*4882a593Smuzhiyunapplication processors (AP) and the secure co-processor (SCP.) When 13*4882a593Smuzhiyunthe AP suspends, the SCP will use the value of this register to 14*4882a593Smuzhiyunprogram an always-on timer before going sleep. When the timer expires, 15*4882a593Smuzhiyunthe SCP will wake up and will then wake the AP. 16*4882a593Smuzhiyun 17*4882a593SmuzhiyunExample: 18*4882a593Smuzhiyun 19*4882a593Smuzhiyun vrtc: rtc@0a8 { 20*4882a593Smuzhiyun compatible = "amlogic,meson-vrtc"; 21*4882a593Smuzhiyun reg = <0x0 0x000a8 0x0 0x4>; 22*4882a593Smuzhiyun }; 23