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Diffstat (limited to 'Documentation/devicetree/bindings/lpddr2')
| -rw-r--r-- | Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt | 52 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/lpddr2/lpddr2.txt | 102 |
2 files changed, 154 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt b/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt new file mode 100644 index 000000000..9ceb19e0c --- /dev/null +++ b/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt @@ -0,0 +1,52 @@ +* AC timing parameters of LPDDR2(JESD209-2) memories for a given speed-bin + +Required properties: +- compatible : Should be "jedec,lpddr2-timings" +- min-freq : minimum DDR clock frequency for the speed-bin. Type is <u32> +- max-freq : maximum DDR clock frequency for the speed-bin. Type is <u32> + +Optional properties: + +The following properties represent AC timing parameters from the memory +data-sheet of the device for a given speed-bin. All these properties are +of type <u32> and the default unit is ps (pico seconds). Parameters with +a different unit have a suffix indicating the unit such as 'tRAS-max-ns' +- tRCD +- tWR +- tRAS-min +- tRRD +- tWTR +- tXP +- tRTP +- tDQSCK-max +- tFAW +- tZQCS +- tZQinit +- tRPab +- tZQCL +- tCKESR +- tRAS-max-ns +- tDQSCK-max-derated + +Example: + +timings_elpida_ECB240ABACN_400mhz: lpddr2-timings@0 { + compatible = "jedec,lpddr2-timings"; + min-freq = <10000000>; + max-freq = <400000000>; + tRPab = <21000>; + tRCD = <18000>; + tWR = <15000>; + tRAS-min = <42000>; + tRRD = <10000>; + tWTR = <7500>; + tXP = <7500>; + tRTP = <7500>; + tCKESR = <15000>; + tDQSCK-max = <5500>; + tFAW = <50000>; + tZQCS = <90000>; + tZQCL = <360000>; + tZQinit = <1000000>; + tRAS-max-ns = <70000>; +}; diff --git a/Documentation/devicetree/bindings/lpddr2/lpddr2.txt b/Documentation/devicetree/bindings/lpddr2/lpddr2.txt new file mode 100644 index 000000000..58354a075 --- /dev/null +++ b/Documentation/devicetree/bindings/lpddr2/lpddr2.txt @@ -0,0 +1,102 @@ +* LPDDR2 SDRAM memories compliant to JEDEC JESD209-2 + +Required properties: +- compatible : Should be one of - "jedec,lpddr2-nvm", "jedec,lpddr2-s2", + "jedec,lpddr2-s4" + + "ti,jedec-lpddr2-s2" should be listed if the memory part is LPDDR2-S2 type + + "ti,jedec-lpddr2-s4" should be listed if the memory part is LPDDR2-S4 type + + "ti,jedec-lpddr2-nvm" should be listed if the memory part is LPDDR2-NVM type + +- density : <u32> representing density in Mb (Mega bits) + +- io-width : <u32> representing bus width. Possible values are 8, 16, and 32 + +Optional properties: + +The following optional properties represent the minimum value of some AC +timing parameters of the DDR device in terms of number of clock cycles. +These values shall be obtained from the device data-sheet. +- tRRD-min-tck +- tWTR-min-tck +- tXP-min-tck +- tRTP-min-tck +- tCKE-min-tck +- tRPab-min-tck +- tRCD-min-tck +- tWR-min-tck +- tRASmin-min-tck +- tCKESR-min-tck +- tFAW-min-tck + +Child nodes: +- The lpddr2 node may have one or more child nodes of type "lpddr2-timings". + "lpddr2-timings" provides AC timing parameters of the device for + a given speed-bin. The user may provide the timings for as many + speed-bins as is required. Please see Documentation/devicetree/ + bindings/lpddr2/lpddr2-timings.txt for more information on "lpddr2-timings" + +Example: + +elpida_ECB240ABACN : lpddr2 { + compatible = "Elpida,ECB240ABACN","jedec,lpddr2-s4"; + density = <2048>; + io-width = <32>; + + tRPab-min-tck = <3>; + tRCD-min-tck = <3>; + tWR-min-tck = <3>; + tRASmin-min-tck = <3>; + tRRD-min-tck = <2>; + tWTR-min-tck = <2>; + tXP-min-tck = <2>; + tRTP-min-tck = <2>; + tCKE-min-tck = <3>; + tCKESR-min-tck = <3>; + tFAW-min-tck = <8>; + + timings_elpida_ECB240ABACN_400mhz: lpddr2-timings@0 { + compatible = "jedec,lpddr2-timings"; + min-freq = <10000000>; + max-freq = <400000000>; + tRPab = <21000>; + tRCD = <18000>; + tWR = <15000>; + tRAS-min = <42000>; + tRRD = <10000>; + tWTR = <7500>; + tXP = <7500>; + tRTP = <7500>; + tCKESR = <15000>; + tDQSCK-max = <5500>; + tFAW = <50000>; + tZQCS = <90000>; + tZQCL = <360000>; + tZQinit = <1000000>; + tRAS-max-ns = <70000>; + }; + + timings_elpida_ECB240ABACN_200mhz: lpddr2-timings@1 { + compatible = "jedec,lpddr2-timings"; + min-freq = <10000000>; + max-freq = <200000000>; + tRPab = <21000>; + tRCD = <18000>; + tWR = <15000>; + tRAS-min = <42000>; + tRRD = <10000>; + tWTR = <10000>; + tXP = <7500>; + tRTP = <7500>; + tCKESR = <15000>; + tDQSCK-max = <5500>; + tFAW = <50000>; + tZQCS = <90000>; + tZQCL = <360000>; + tZQinit = <1000000>; + tRAS-max-ns = <70000>; + }; + +} |