1*c66ec88fSEmmanuel Vadot* Maxim/Dallas Semiconductor DS-1302 RTC 2*c66ec88fSEmmanuel Vadot 3*c66ec88fSEmmanuel VadotSimple device which could be used to store date/time between reboots. 4*c66ec88fSEmmanuel Vadot 5*c66ec88fSEmmanuel VadotThe device uses the standard MicroWire half-duplex transfer timing. 6*c66ec88fSEmmanuel VadotMaster output is set on low clock and sensed by the RTC on the rising 7*c66ec88fSEmmanuel Vadotedge. Master input is set by the RTC on the trailing edge and is sensed 8*c66ec88fSEmmanuel Vadotby the master on low clock. 9*c66ec88fSEmmanuel Vadot 10*c66ec88fSEmmanuel VadotRequired properties: 11*c66ec88fSEmmanuel Vadot 12*c66ec88fSEmmanuel Vadot- compatible : Should be "maxim,ds1302" 13*c66ec88fSEmmanuel Vadot 14*c66ec88fSEmmanuel VadotRequired SPI properties: 15*c66ec88fSEmmanuel Vadot 16*c66ec88fSEmmanuel Vadot- reg : Should be address of the device chip select within 17*c66ec88fSEmmanuel Vadot the controller. 18*c66ec88fSEmmanuel Vadot 19*c66ec88fSEmmanuel Vadot- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V, 20*c66ec88fSEmmanuel Vadot and 2MHz if powered at 5V. 21*c66ec88fSEmmanuel Vadot 22*c66ec88fSEmmanuel Vadot- spi-3wire : The device has a shared signal IN/OUT line. 23*c66ec88fSEmmanuel Vadot 24*c66ec88fSEmmanuel Vadot- spi-lsb-first : DS-1302 requires least significant bit first 25*c66ec88fSEmmanuel Vadot transfers. 26*c66ec88fSEmmanuel Vadot 27*c66ec88fSEmmanuel Vadot- spi-cs-high: DS-1302 has active high chip select line. This is 28*c66ec88fSEmmanuel Vadot required unless inverted in hardware. 29*c66ec88fSEmmanuel Vadot 30*c66ec88fSEmmanuel VadotExample: 31*c66ec88fSEmmanuel Vadot 32*c66ec88fSEmmanuel Vadotspi@901c { 33*c66ec88fSEmmanuel Vadot #address-cells = <1>; 34*c66ec88fSEmmanuel Vadot #size-cells = <0>; 35*c66ec88fSEmmanuel Vadot compatible = "icpdas,lp8841-spi-rtc"; 36*c66ec88fSEmmanuel Vadot reg = <0x901c 0x1>; 37*c66ec88fSEmmanuel Vadot 38*c66ec88fSEmmanuel Vadot rtc@0 { 39*c66ec88fSEmmanuel Vadot compatible = "maxim,ds1302"; 40*c66ec88fSEmmanuel Vadot reg = <0>; 41*c66ec88fSEmmanuel Vadot spi-max-frequency = <500000>; 42*c66ec88fSEmmanuel Vadot spi-3wire; 43*c66ec88fSEmmanuel Vadot spi-lsb-first; 44*c66ec88fSEmmanuel Vadot spi-cs-high; 45*c66ec88fSEmmanuel Vadot }; 46*c66ec88fSEmmanuel Vadot}; 47