dt-bindings: memory: lpddr2-timings: convert to dtschema

Convert the LPDDR2 memory timings bindings to DT schema format.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220206135807.211767-2-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2-timings.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr2-timings.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LPDDR2 SDRAM AC timing parameters for a given speed-bin
+
+maintainers:
+  - Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
+
+properties:
+  compatible:
+    const: jedec,lpddr2-timings
+
+  max-freq:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Maximum DDR clock frequency for the speed-bin, in Hz.
+
+  min-freq:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Minimum DDR clock frequency for the speed-bin, in Hz.
+
+  tCKESR:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      CKE minimum pulse width during SELF REFRESH (low pulse width during
+      SELF REFRESH) in pico seconds.
+
+  tDQSCK-max:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      DQS output data access time from CK_t/CK_c in pico seconds.
+
+  tDQSCK-max-derated:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      DQS output data access time from CK_t/CK_c, temperature de-rated, in pico
+      seconds.
+
+  tFAW:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Four-bank activate window in pico seconds.
+
+  tRAS-max-ns:
+    description: |
+      Row active time in nano seconds.
+
+  tRAS-min:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Row active time in pico seconds.
+
+  tRCD:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      RAS-to-CAS delay in pico seconds.
+
+  tRPab:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Row precharge time (all banks) in pico seconds.
+
+  tRRD:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Active bank A to active bank B in pico seconds.
+
+  tRTP:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Internal READ to PRECHARGE command delay in pico seconds.
+
+  tWR:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      WRITE recovery time in pico seconds.
+
+  tWTR:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Internal WRITE-to-READ command delay in pico seconds.
+
+  tXP:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Exit power-down to next valid command delay in pico seconds.
+
+  tZQCL:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Long calibration time in pico seconds.
+
+  tZQCS:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Short calibration time in pico seconds.
+
+  tZQinit:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Initialization calibration time in pico seconds.
+
+required:
+  - compatible
+  - min-freq
+  - max-freq
+
+additionalProperties: false
+
+examples:
+  - |
+    timings {
+        compatible = "jedec,lpddr2-timings";
+        min-freq = <10000000>;
+        max-freq = <400000000>;
+        tCKESR = <15000>;
+        tDQSCK-max = <5500>;
+        tFAW = <50000>;
+        tRAS-max-ns = <70000>;
+        tRAS-min = <42000>;
+        tRPab = <21000>;
+        tRCD = <18000>;
+        tRRD = <10000>;
+        tRTP = <7500>;
+        tWR = <15000>;
+        tWTR = <7500>;
+        tXP = <7500>;
+        tZQCL = <360000>;
+        tZQCS = <90000>;
+        tZQinit = <1000000>;
+    };

Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2.yaml

@@ -142,14 +142,12 @@ properties:
 
 patternProperties:
   "^lpddr2-timings":
-    type: object
+    $ref: jedec,lpddr2-timings.yaml
     description: |
       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/memory-controllers/ddr/lpddr2-timings.txt for more information
-      on "lpddr2-timings".
+      speed-bins as is required.
 
 required:
   - compatible

Documentation/devicetree/bindings/memory-controllers/ddr/lpddr2-timings.txt

-* 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>;
-};