1* LPDDR2 SDRAM memories compliant to JEDEC JESD209-2 2 3Required properties: 4- compatible : Should be one of - "jedec,lpddr2-nvm", "jedec,lpddr2-s2", 5 "jedec,lpddr2-s4" 6 7 "ti,jedec-lpddr2-s2" should be listed if the memory part is LPDDR2-S2 type 8 9 "ti,jedec-lpddr2-s4" should be listed if the memory part is LPDDR2-S4 type 10 11 "ti,jedec-lpddr2-nvm" should be listed if the memory part is LPDDR2-NVM type 12 13- density : <u32> representing density in Mb (Mega bits) 14 15- io-width : <u32> representing bus width. Possible values are 8, 16, and 32 16 17Optional properties: 18 19The following optional properties represent the minimum value of some AC 20timing parameters of the DDR device in terms of number of clock cycles. 21These values shall be obtained from the device data-sheet. 22- tRRD-min-tck 23- tWTR-min-tck 24- tXP-min-tck 25- tRTP-min-tck 26- tCKE-min-tck 27- tRPab-min-tck 28- tRCD-min-tck 29- tWR-min-tck 30- tRASmin-min-tck 31- tCKESR-min-tck 32- tFAW-min-tck 33 34Child nodes: 35- The lpddr2 node may have one or more child nodes of type "lpddr2-timings". 36 "lpddr2-timings" provides AC timing parameters of the device for 37 a given speed-bin. The user may provide the timings for as many 38 speed-bins as is required. Please see Documentation/devicetree/ 39 bindings/ddr/lpddr2-timings.txt for more information on "lpddr2-timings" 40 41Example: 42 43elpida_ECB240ABACN : lpddr2 { 44 compatible = "Elpida,ECB240ABACN","jedec,lpddr2-s4"; 45 density = <2048>; 46 io-width = <32>; 47 48 tRPab-min-tck = <3>; 49 tRCD-min-tck = <3>; 50 tWR-min-tck = <3>; 51 tRASmin-min-tck = <3>; 52 tRRD-min-tck = <2>; 53 tWTR-min-tck = <2>; 54 tXP-min-tck = <2>; 55 tRTP-min-tck = <2>; 56 tCKE-min-tck = <3>; 57 tCKESR-min-tck = <3>; 58 tFAW-min-tck = <8>; 59 60 timings_elpida_ECB240ABACN_400mhz: lpddr2-timings@0 { 61 compatible = "jedec,lpddr2-timings"; 62 min-freq = <10000000>; 63 max-freq = <400000000>; 64 tRPab = <21000>; 65 tRCD = <18000>; 66 tWR = <15000>; 67 tRAS-min = <42000>; 68 tRRD = <10000>; 69 tWTR = <7500>; 70 tXP = <7500>; 71 tRTP = <7500>; 72 tCKESR = <15000>; 73 tDQSCK-max = <5500>; 74 tFAW = <50000>; 75 tZQCS = <90000>; 76 tZQCL = <360000>; 77 tZQinit = <1000000>; 78 tRAS-max-ns = <70000>; 79 }; 80 81 timings_elpida_ECB240ABACN_200mhz: lpddr2-timings@1 { 82 compatible = "jedec,lpddr2-timings"; 83 min-freq = <10000000>; 84 max-freq = <200000000>; 85 tRPab = <21000>; 86 tRCD = <18000>; 87 tWR = <15000>; 88 tRAS-min = <42000>; 89 tRRD = <10000>; 90 tWTR = <10000>; 91 tXP = <7500>; 92 tRTP = <7500>; 93 tCKESR = <15000>; 94 tDQSCK-max = <5500>; 95 tFAW = <50000>; 96 tZQCS = <90000>; 97 tZQCL = <360000>; 98 tZQinit = <1000000>; 99 tRAS-max-ns = <70000>; 100 }; 101 102} 103