xref: /kernel/linux/linux-5.10/Documentation/devicetree/bindings/ddr/lpddr3.txt

* LPDDR3 SDRAM memories compliant to JEDEC JESD209-3C

Required properties:
- compatible : Should be "<vendor>,<type>", and generic value "jedec,lpddr3".
  Example "<vendor>,<type>" values:
    "samsung,K3QF2F20DB"

- density  : <u32> representing density in Mb (Mega bits)
- io-width : <u32> representing bus width. Possible values are 8, 16, 32, 64
- #address-cells: Must be set to 1
- #size-cells: Must be set to 0

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.
- tRFC-min-tck
- tRRD-min-tck
- tRPab-min-tck
- tRPpb-min-tck
- tRCD-min-tck
- tRC-min-tck
- tRAS-min-tck
- tWTR-min-tck
- tWR-min-tck
- tRTP-min-tck
- tW2W-C2C-min-tck
- tR2R-C2C-min-tck
- tWL-min-tck
- tDQSCK-min-tck
- tRL-min-tck
- tFAW-min-tck
- tXSR-min-tck
- tXP-min-tck
- tCKE-min-tck
- tCKESR-min-tck
- tMRD-min-tck

Child nodes:
- The lpddr3 node may have one or more child nodes of type "lpddr3-timings".
  "lpddr3-timings" provides AC timing parameters of the device for
  a given speed-bin. Please see Documentation/devicetree/
  bindings/ddr/lpddr3-timings.txt for more information on "lpddr3-timings"

Example:

samsung_K3QF2F20DB: lpddr3 {
	compatible	= "samsung,K3QF2F20DB", "jedec,lpddr3";
	density		= <16384>;
	io-width	= <32>;
	#address-cells	= <1>;
	#size-cells	= <0>;

	tRFC-min-tck		= <17>;
	tRRD-min-tck		= <2>;
	tRPab-min-tck		= <2>;
	tRPpb-min-tck		= <2>;
	tRCD-min-tck		= <3>;
	tRC-min-tck		= <6>;
	tRAS-min-tck		= <5>;
	tWTR-min-tck		= <2>;
	tWR-min-tck		= <7>;
	tRTP-min-tck		= <2>;
	tW2W-C2C-min-tck	= <0>;
	tR2R-C2C-min-tck	= <0>;
	tWL-min-tck		= <8>;
	tDQSCK-min-tck		= <5>;
	tRL-min-tck		= <14>;
	tFAW-min-tck		= <5>;
	tXSR-min-tck		= <12>;
	tXP-min-tck		= <2>;
	tCKE-min-tck		= <2>;
	tCKESR-min-tck		= <2>;
	tMRD-min-tck		= <5>;

	timings_samsung_K3QF2F20DB_800mhz: lpddr3-timings@800000000 {
		compatible	= "jedec,lpddr3-timings";
		/* workaround: 'reg' shows max-freq */
		reg		= <800000000>;
		min-freq	= <100000000>;
		tRFC		= <65000>;
		tRRD		= <6000>;
		tRPab		= <12000>;
		tRPpb		= <12000>;
		tRCD		= <10000>;
		tRC		= <33750>;
		tRAS		= <23000>;
		tWTR		= <3750>;
		tWR		= <7500>;
		tRTP		= <3750>;
		tW2W-C2C	= <0>;
		tR2R-C2C	= <0>;
		tFAW		= <25000>;
		tXSR		= <70000>;
		tXP		= <3750>;
		tCKE		= <3750>;
		tCKESR		= <3750>;
		tMRD		= <7000>;
	};
}