xref: /OK3568_Linux_fs/kernel/Documentation/devicetree/bindings/ddr/lpddr2-timings.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun* AC timing parameters of LPDDR2(JESD209-2) memories for a given speed-bin
2*4882a593Smuzhiyun
3*4882a593SmuzhiyunRequired properties:
4*4882a593Smuzhiyun- compatible : Should be "jedec,lpddr2-timings"
5*4882a593Smuzhiyun- min-freq : minimum DDR clock frequency for the speed-bin. Type is <u32>
6*4882a593Smuzhiyun- max-freq : maximum DDR clock frequency for the speed-bin. Type is <u32>
7*4882a593Smuzhiyun
8*4882a593SmuzhiyunOptional properties:
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunThe following properties represent AC timing parameters from the memory
11*4882a593Smuzhiyundata-sheet of the device for a given speed-bin. All these properties are
12*4882a593Smuzhiyunof type <u32> and the default unit is ps (pico seconds). Parameters with
13*4882a593Smuzhiyuna different unit have a suffix indicating the unit such as 'tRAS-max-ns'
14*4882a593Smuzhiyun- tRCD
15*4882a593Smuzhiyun- tWR
16*4882a593Smuzhiyun- tRAS-min
17*4882a593Smuzhiyun- tRRD
18*4882a593Smuzhiyun- tWTR
19*4882a593Smuzhiyun- tXP
20*4882a593Smuzhiyun- tRTP
21*4882a593Smuzhiyun- tDQSCK-max
22*4882a593Smuzhiyun- tFAW
23*4882a593Smuzhiyun- tZQCS
24*4882a593Smuzhiyun- tZQinit
25*4882a593Smuzhiyun- tRPab
26*4882a593Smuzhiyun- tZQCL
27*4882a593Smuzhiyun- tCKESR
28*4882a593Smuzhiyun- tRAS-max-ns
29*4882a593Smuzhiyun- tDQSCK-max-derated
30*4882a593Smuzhiyun
31*4882a593SmuzhiyunExample:
32*4882a593Smuzhiyun
33*4882a593Smuzhiyuntimings_elpida_ECB240ABACN_400mhz: lpddr2-timings@0 {
34*4882a593Smuzhiyun	compatible	= "jedec,lpddr2-timings";
35*4882a593Smuzhiyun	min-freq	= <10000000>;
36*4882a593Smuzhiyun	max-freq	= <400000000>;
37*4882a593Smuzhiyun	tRPab		= <21000>;
38*4882a593Smuzhiyun	tRCD		= <18000>;
39*4882a593Smuzhiyun	tWR		= <15000>;
40*4882a593Smuzhiyun	tRAS-min	= <42000>;
41*4882a593Smuzhiyun	tRRD		= <10000>;
42*4882a593Smuzhiyun	tWTR		= <7500>;
43*4882a593Smuzhiyun	tXP		= <7500>;
44*4882a593Smuzhiyun	tRTP		= <7500>;
45*4882a593Smuzhiyun	tCKESR		= <15000>;
46*4882a593Smuzhiyun	tDQSCK-max	= <5500>;
47*4882a593Smuzhiyun	tFAW		= <50000>;
48*4882a593Smuzhiyun	tZQCS		= <90000>;
49*4882a593Smuzhiyun	tZQCL		= <360000>;
50*4882a593Smuzhiyun	tZQinit		= <1000000>;
51*4882a593Smuzhiyun	tRAS-max-ns	= <70000>;
52*4882a593Smuzhiyun};
53