device tree bindings for LPDDR2 SDRAM memories compliant
to JESD209-2 standard.
The 'lpddr2' binding in-turn uses another binding 'lpddr2-timings'
for specifying the AC timing parameters of the memory device at
different speed-bins.
Cc: Rajendra Nayak <rnayak@xxxxxx>
Cc: Benoit Cousson <b-cousson@xxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Signed-off-by: Aneesh V <aneesh@xxxxxx>
Changes in RFC v2:
* Removed the "manufacturer" property and added it in
compatible property instead
* Changed the DDR device names in example to indicate
the part number
Changes in RFC v3:
* Removed DDR3 support
* Fixed review comments on RFC v2
---
.../devicetree/bindings/lpddr2/lpddr2-timings.txt | 51 ++++++++++
.../devicetree/bindings/lpddr2/lpddr2.txt | 102 ++++++++++++++++++++
2 files changed, 153 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt
create mode 100644 Documentation/devicetree/bindings/lpddr2/lpddr2.txt
diff --git a/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt b/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt
new file mode 100644
index 0000000..1483841
--- /dev/null
+++ b/Documentation/devicetree/bindings/lpddr2/lpddr2-timings.txt
@@ -0,0 +1,51 @@
+* 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
+
+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 0000000..9c175f0
--- /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>;
+ tRP = <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>;
+ tZQoper = <360000>;
+ tZQinit = <1000000>;
+ tRAS-max-ns = <70000>;
+ };
+
+ timings_elpida_ECB240ABACN_200mhz: lpddr2-timings@1 {
+ compatible = "jedec,lpddr2-timings";
+ min-freq = <10000000>;
+ max-freq = <200000000>;
+ tRP = <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>;
+ tZQoper = <360000>;
+ tZQinit = <1000000>;
+ tRAS-max-ns = <70000>;
+ };
+
+}
--
1.7.1
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