[PATCH v2 3/5] dt-bindings: memory: additional compatible strings for Broadcom DPFE

From: Markus Mayer <mmayer@broadcom.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	Rob Herring <robh+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>
Cc: Markus Mayer <mmayer@broadcom.com>,
	Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>,
	Device Tree Mailing List <devicetree@vger.kernel.org>
Subject: [PATCH v2 3/5] dt-bindings: memory: additional compatible strings for Broadcom DPFE
Date: Fri, 19 Jan 2024 13:52:26 -0800	[thread overview]
Message-ID: <20240119215231.758844-4-mmayer@broadcom.com> (raw)
In-Reply-To: <20240119215231.758844-1-mmayer@broadcom.com>

Add versioned compatible strings for Broadcom DPFE. These take the form
brcm,dpfe-cpu-v<N> where <N> is a number from 1 to 4.

The chip-specific strings have been kept for compatibility purposes
(hardware is in the field). For new chips, the properly versioned
compatible string should be used.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
---
 .../memory-controllers/brcm,dpfe-cpu.yaml     | 21 ++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml b/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
index 3f00bc2fd3ec..42c8160d95d1 100644
--- a/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
@@ -10,9 +10,28 @@ maintainers:
   - Krzysztof Kozlowski <krzk@kernel.org>
   - Markus Mayer <mmayer@broadcom.com>
 
+description: |
+
+  The DCPU (DDR PHY Front End CPU) interfaces directly with the DDR PHY
+  chip on Broadcom STB SoCs. An API exists for other agents to retrieve
+  or set certain DDR PHY chip parameters by JEDEC.
+
+  Different, incompatible versions of this API have been created over
+  time. The API has changed for the some chips as development progressed
+  and features were added or changed.
+
+  We rely on the boot firmware (which already knows the API version
+  required) to populate Device Tree with the corresponding compatible
+  string.
+
 properties:
   compatible:
     items:
+      - enum:
+          - brcm,dpfe-cpu-v1
+          - brcm,dpfe-cpu-v2
+          - brcm,dpfe-cpu-v3
+          - brcm,dpfe-cpu-v4
       - enum:
           - brcm,bcm7271-dpfe-cpu
           - brcm,bcm7268-dpfe-cpu
@@ -41,7 +60,7 @@ additionalProperties: false
 examples:
   - |
     dpfe-cpu@f1132000 {
-        compatible = "brcm,bcm7271-dpfe-cpu";
+        compatible = "brcm,dpfe-cpu-v1", "brcm,bcm7271-dpfe-cpu";
         reg = <0xf1132000 0x180>,
               <0xf1134000 0x1000>,
               <0xf1138000 0x4000>;
-- 
2.43.0


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