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From:   Julius Werner <jwerner@chromium.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Rob Herring <robh+dt@kernel.org>
Cc:     Dmitry Osipenko <digetx@gmail.com>,
        Doug Anderson <dianders@chromium.org>,
        Jian-Jia Su <jjsu@google.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Julius Werner <jwerner@chromium.org>
Subject: [PATCH 2/4 v4] dt-bindings: memory: Add numeric LPDDR compatible string variant
Date:   Wed, 14 Sep 2022 17:32:20 -0700
Message-Id: <20220915003222.1296421-2-jwerner@chromium.org>
In-Reply-To: <20220915003222.1296421-1-jwerner@chromium.org>
References: <20220915003222.1296421-1-jwerner@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This patch allows a new kind of compatible string for LPDDR parts in the
device tree bindings, in addition to the existing hardcoded
<vendor>,<part-number> strings. The new format contains manufacturer and
part (revision) information in numerical form, such as lpddr3-ff,0201
for an LPDDR3 part with manufacturer ID ff and revision ID 0201. This
helps cases where LPDDR parts are probed at runtime by boot firmware and
cannot be matched to hardcoded part numbers, such as the firmware on the
qcom/sc7280-herobrine boards does (which supports 4 different memory
configurations at the moment, and more are expected to be added later at
a point where the boot firmware can no longer be updated to specifically
accomodate them).

Signed-off-by: Julius Werner <jwerner@chromium.org>
---
 .../memory-controllers/ddr/jedec,lpddr-props.yaml    | 10 ++++++++++
 .../memory-controllers/ddr/jedec,lpddr2.yaml         |  8 +++++---
 .../memory-controllers/ddr/jedec,lpddr3.yaml         | 12 ++++++++----
 3 files changed, 23 insertions(+), 7 deletions(-)

Changelog:

- v2
  - Updated commit message to describe intended use case as an example
- v3
  - no changes
- v4
  - no changes

diff --git a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-props.yaml b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-props.yaml
index 02700ac3c387ec..4114cfa8de67f1 100644
--- a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-props.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr-props.yaml
@@ -15,6 +15,16 @@ maintainers:
   - Krzysztof Kozlowski <krzk@kernel.org>
 
 properties:
+  compatible:
+    description:
+      Compatible strings can be either explicit vendor names and part numbers
+      (e.g. elpida,ECB240ABACN), or generated strings of the form
+      lpddrX-YY,ZZZZ where X is the LPDDR version, YY is the manufacturer ID
+      (from MR5) and ZZZZ is the revision ID (from MR6 and MR7). Both IDs are
+      formatted in lower case hexadecimal representation with leading zeroes.
+      The latter form can be useful when LPDDR nodes are created at runtime by
+      boot firmware that doesn't have access to static part number information.
+
   revision-id:
     $ref: /schemas/types.yaml#/definitions/uint32-array
     description:
diff --git a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2.yaml b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2.yaml
index e5e15d288d89b2..a237bc259273bf 100644
--- a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr2.yaml
@@ -20,13 +20,15 @@ properties:
               - elpida,ECB240ABACN
               - elpida,B8132B2PB-6D-F
           - enum:
-              - jedec,lpddr2-s4
-      - items:
-          - enum:
+              - jedec,lpddr2-nvm
               - jedec,lpddr2-s2
+              - jedec,lpddr2-s4
       - items:
+          - pattern: "^lpddr2-[0-9a-f]{2},[0-9a-f]{4}$"
           - enum:
               - jedec,lpddr2-nvm
+              - jedec,lpddr2-s2
+              - jedec,lpddr2-s4
 
   revision-id1:
     $ref: /schemas/types.yaml#/definitions/uint32
diff --git a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr3.yaml b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr3.yaml
index 0f7ab51842ae09..e328a1195ba646 100644
--- a/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr3.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/ddr/jedec,lpddr3.yaml
@@ -14,10 +14,14 @@ allOf:
 
 properties:
   compatible:
-    items:
-      - enum:
-          - samsung,K3QF2F20DB
-      - const: jedec,lpddr3
+    oneOf:
+      - items:
+          - enum:
+              - samsung,K3QF2F20DB
+          - const: jedec,lpddr3
+      - items:
+          - pattern: "^lpddr3-[0-9a-f]{2},[0-9a-f]{4}$"
+          - const: jedec,lpddr3
 
   '#address-cells':
     const: 1
-- 
2.31.0