linux-kernel - [PATCH v2 1/3] dt-bindings: power: Introduce 'assigned-performance-states' property

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Message-Id: <1622095949-2014-2-git-send-email-rnayak@codeaurora.org>
Date:   Thu, 27 May 2021 11:42:27 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     ulf.hansson@...aro.org, robh+dt@...nel.org,
        bjorn.andersson@...aro.org, viresh.kumar@...aro.org
Cc:     linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        swboyd@...omium.org, rojay@...eaurora.org,
        Rajendra Nayak <rnayak@...eaurora.org>
Subject: [PATCH v2 1/3] dt-bindings: power: Introduce 'assigned-performance-states' property

While most devices within power-domains which support performance states,
scale the performance state dynamically, some devices might want to
set a static/default performance state while the device is active.
These devices typically would also run off a fixed clock and not support
dynamically scaling the device's performance, also known as DVFS techniques.
Add a property 'assigned-performance-states' which client devices can
use to set this default performance state on their power-domains.

Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
---
 .../devicetree/bindings/power/power-domain.yaml    | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
index aed51e9..88cebf2 100644
--- a/Documentation/devicetree/bindings/power/power-domain.yaml
+++ b/Documentation/devicetree/bindings/power/power-domain.yaml
@@ -66,6 +66,19 @@ properties:
       by the given provider should be subdomains of the domain specified
       by this binding.
 
+  assigned-performance-states:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+       Some devices might need to configure their power domains in a default
+       performance state while the device is active. These devices typically
+       would also run off a fixed clock and not support dynamically scaling the
+       device's performance, also known as DVFS techniques. The list of performance
+       state values should correspond to the list of power domains specified as part
+       of the power-domains property. Each cell corresponds to one power-domain.
+       A value of 0 can be used for power-domains with no performance state
+       requirement. In case the power-domains have OPP tables associated, the values
+       here would typically match with one of the entries in the OPP table.
+
 required:
   - "#power-domain-cells"
 
@@ -131,3 +144,40 @@ examples:
             min-residency-us = <7000>;
         };
     };
+
+  - |
+    parent4: power-controller@...40000 {
+        compatible = "foo,power-controller";
+        reg = <0x12340000 0x1000>;
+        #power-domain-cells = <0>;
+    };
+
+    parent5: power-controller@...10000 {
+        compatible = "foo,power-controller";
+        reg = <0x43210000 0x1000>;
+        #power-domain-cells = <0>;
+        operating-points-v2 = <&power_opp_table>;
+
+        power_opp_table: opp-table {
+            compatible = "operating-points-v2";
+
+            power_opp_low: opp1 {
+                opp-level = <16>;
+            };
+
+            rpmpd_opp_ret: opp2 {
+                opp-level = <64>;
+            };
+
+            rpmpd_opp_svs: opp3 {
+                opp-level = <256>;
+            };
+        };
+    };
+
+    child4: consumer@...41000 {
+        compatible = "foo,consumer";
+        reg = <0x12341000 0x1000>;
+        power-domains = <&parent4>, <&parent5>;
+        assigned-performance-states = <0>, <256>;
+    };
-- 
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