1*d25a5ed3SSergey Yanovich* Maxim/Dallas Semiconductor DS-1302 RTC 2*d25a5ed3SSergey Yanovich 3*d25a5ed3SSergey YanovichSimple device which could be used to store date/time between reboots. 4*d25a5ed3SSergey Yanovich 5*d25a5ed3SSergey YanovichThe device uses the standard MicroWire half-duplex transfer timing. 6*d25a5ed3SSergey YanovichMaster output is set on low clock and sensed by the RTC on the rising 7*d25a5ed3SSergey Yanovichedge. Master input is set by the RTC on the trailing edge and is sensed 8*d25a5ed3SSergey Yanovichby the master on low clock. 9*d25a5ed3SSergey Yanovich 10*d25a5ed3SSergey YanovichRequired properties: 11*d25a5ed3SSergey Yanovich 12*d25a5ed3SSergey Yanovich- compatible : Should be "maxim,ds1302" 13*d25a5ed3SSergey Yanovich 14*d25a5ed3SSergey YanovichRequired SPI properties: 15*d25a5ed3SSergey Yanovich 16*d25a5ed3SSergey Yanovich- reg : Should be address of the device chip select within 17*d25a5ed3SSergey Yanovich the controller. 18*d25a5ed3SSergey Yanovich 19*d25a5ed3SSergey Yanovich- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V, 20*d25a5ed3SSergey Yanovich and 2MHz if powered at 5V. 21*d25a5ed3SSergey Yanovich 22*d25a5ed3SSergey Yanovich- spi-3wire : The device has a shared signal IN/OUT line. 23*d25a5ed3SSergey Yanovich 24*d25a5ed3SSergey Yanovich- spi-lsb-first : DS-1302 requires least significant bit first 25*d25a5ed3SSergey Yanovich transfers. 26*d25a5ed3SSergey Yanovich 27*d25a5ed3SSergey Yanovich- spi-cs-high: DS-1302 has active high chip select line. This is 28*d25a5ed3SSergey Yanovich required unless inverted in hardware. 29*d25a5ed3SSergey Yanovich 30*d25a5ed3SSergey YanovichExample: 31*d25a5ed3SSergey Yanovich 32*d25a5ed3SSergey Yanovichspi@901c { 33*d25a5ed3SSergey Yanovich #address-cells = <1>; 34*d25a5ed3SSergey Yanovich #size-cells = <0>; 35*d25a5ed3SSergey Yanovich compatible = "icpdas,lp8841-spi-rtc"; 36*d25a5ed3SSergey Yanovich reg = <0x901c 0x1>; 37*d25a5ed3SSergey Yanovich 38*d25a5ed3SSergey Yanovich rtc@0 { 39*d25a5ed3SSergey Yanovich compatible = "maxim,ds1302"; 40*d25a5ed3SSergey Yanovich reg = <0>; 41*d25a5ed3SSergey Yanovich spi-max-frequency = <500000>; 42*d25a5ed3SSergey Yanovich spi-3wire; 43*d25a5ed3SSergey Yanovich spi-lsb-first; 44*d25a5ed3SSergey Yanovich spi-cs-high; 45*d25a5ed3SSergey Yanovich }; 46*d25a5ed3SSergey Yanovich}; 47