linux-kernel - [PATCH v5] dt-bindings: opp: operating-points-v2-ti-cpu: Describe opp-supported-hw

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Message-ID: <20240919-b4-opp-dt-binding-fix-v5-1-199216dc0991@ti.com>
Date: Thu, 19 Sep 2024 18:43:40 +0530
From: Dhruva Gole <d-gole@...com>
To: Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen
 Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski
	<krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>
CC: Viresh Kumar <viresh.kumar@...aro.org>,
        Vignesh Raghavendra
	<vigneshr@...com>, <linux-pm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Dhruva Gole <d-gole@...com>
Subject: [PATCH v5] dt-bindings: opp: operating-points-v2-ti-cpu: Describe
 opp-supported-hw

It seems like we missed migrating the complete information from the old
DT binding where we had described what the opp-supported-hw is supposed
to describe. Hence, bring back the description from the previous binding
to the current one along with a bit more context on what the values are
supposed to be.

Fixes: e576a9a8603f ("dt-bindings: cpufreq: Convert ti-cpufreq to json schema")
Signed-off-by: Dhruva Gole <d-gole@...com>
---
Changes in v5:
- Fix the new lines inserted to seperate paragraphs.
- /eg./example,/
- Fix Odd line wrapping
- Link to v4: https://lore.kernel.org/all/20240918173431.GA1833339-robh@kernel.org/

Changes in v4:
- Fix dt_binding_check errors on previous revision.
- As per Rob's suggestion, used a blank line in between description
  and the paragraph.
- Reworded the description a bit.
- Link to v3: https://lore.kernel.org/all/20240917095252.1292321-1-d-gole@ti.com/

Changes in v3:
- Use the items: and then provide description for both required items.
  This tries to address Rob's comments on previous revision.
- I've not use min/max Items as the 2 descriptions items implicitly
  imply that number of bitfields needed are 2.
- Link to v2: https://lore.kernel.org/all/20240905-b4-opp-dt-binding-fix-v2-1-1e3d2a06748d@ti.com/

Changes in v2:
- Drop the patch where I updated Maintainers since it's already picked
  by Viresh.
- Add more details of how to populate the property based on device
  documents like TRM/ datasheet.
- Link to v1: https://lore.kernel.org/r/20240903-b4-opp-dt-binding-fix-v1-0-f7e186456d9f@ti.com
---
 .../bindings/opp/operating-points-v2-ti-cpu.yaml     | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/opp/operating-points-v2-ti-cpu.yaml b/Documentation/devicetree/bindings/opp/operating-points-v2-ti-cpu.yaml
index fd0c8d5c5f3e7eacecb74523e052c2cbb076ce20..624d1f3f1382fb9cae576c6c4919a9be875cf061 100644
--- a/Documentation/devicetree/bindings/opp/operating-points-v2-ti-cpu.yaml
+++ b/Documentation/devicetree/bindings/opp/operating-points-v2-ti-cpu.yaml
@@ -45,7 +45,25 @@ patternProperties:
       clock-latency-ns: true
       opp-hz: true
       opp-microvolt: true
-      opp-supported-hw: true
+      opp-supported-hw:
+        items:
+          items:
+            - description:
+                The revision of the SoC the OPP is supported by.
+                This can be easily obtained from the datasheet of the
+                part being ordered/used. For example, it will be 0x01 for SR1.0
+
+            - description:
+                The eFuse bits that indicate the particular OPP is available.
+                The device datasheet has a table talking about Device Speed Grades.
+                This table is to be sorted with only the unique elements of the
+                MAXIMUM OPERATING FREQUENCY starting from the first row which
+                tells the lowest OPP, to the highest. The corresponding bits
+                need to be set based on N elements of speed grade the device supports.
+                So, if there are 3 possible unique MAXIMUM OPERATING FREQUENCY
+                in the table, then BIT(0) | (1) | (2) will be set, which means
+                the value shall be 0x7.
+
       opp-suspend: true
       turbo-mode: true
 

---
base-commit: 3621a2c9142bd490af0666c0c02d52d60ce0d2a5
change-id: 20240903-b4-opp-dt-binding-fix-73c6829751d2

Best regards,
-- 
Dhruva Gole <d-gole@...com>