linux-kernel - [RFC 1/2] dt-bindings: connector: Add property to set pd timer values

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Message-ID: <20240911000715.554184-2-amitsd@google.com>
Date: Tue, 10 Sep 2024 17:07:05 -0700
From: Amit Sunil Dhamne <amitsd@...gle.com>
To: robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, 
	heikki.krogerus@...ux.intel.com, gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org, kyletso@...gle.com, rdbabiera@...gle.com, 
	Amit Sunil Dhamne <amitsd@...gle.com>, Badhri Jagan Sridharan <badhri@...gle.com>, linux-usb@...r.kernel.org, 
	devicetree@...r.kernel.org
Subject: [RFC 1/2] dt-bindings: connector: Add property to set pd timer values

This commit adds a new property "pd-timers" to enable setting of
platform/board specific pd timer values for timers that have a range of
acceptable values.

Cc: Badhri Jagan Sridharan <badhri@...gle.com>
Cc: linux-usb@...r.kernel.org
Cc: devicetree@...r.kernel.org
Signed-off-by: Amit Sunil Dhamne <amitsd@...gle.com>
---
 .../bindings/connector/usb-connector.yaml     | 23 +++++++++++++++++++
 include/dt-bindings/usb/pd.h                  |  8 +++++++
 2 files changed, 31 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
index fb216ce68bb3..9be4ed12f13c 100644
--- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
+++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
@@ -253,6 +253,16 @@ properties:
 
     additionalProperties: false
 
+  pd-timers:
+    description: An array of u32 integers, where an even index (i) is the timer (referenced in
+      dt-bindings/usb/pd.h) and the odd index (i+1) is the timer value in ms (refer
+      "Table 6-68 Time Values" of "USB Power Delivery Specification Revision 3.0, Version 1.2 " for
+      the appropriate value). For certain timers the PD spec defines a range rather than a fixed
+      value. The timers may need to be tuned based on the platform. This dt property allows the user
+      to assign specific values based on the platform. If these values are not explicitly defined,
+      TCPM will use a valid default value for such timers.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
 dependencies:
   sink-vdos-v1: [ sink-vdos ]
   sink-vdos: [ sink-vdos-v1 ]
@@ -478,3 +488,16 @@ examples:
             };
         };
     };
+
+  # USB-C connector with PD timers
+  - |
+    #include <dt-bindings/usb/pd.h>
+    usb {
+        connector {
+            compatible = "usb-c-connector";
+            label = "USB-C";
+            pd-timers =
+                <PD_TIMER_SINK_WAIT_CAP 600>,
+                <PD_TIMER_CC_DEBOUNCE 170>;
+        };
+    };
diff --git a/include/dt-bindings/usb/pd.h b/include/dt-bindings/usb/pd.h
index e6526b138174..6c58c30f3f39 100644
--- a/include/dt-bindings/usb/pd.h
+++ b/include/dt-bindings/usb/pd.h
@@ -465,4 +465,12 @@
 	 | ((vbm) & 0x3) << 15 | (curr) << 14 | ((vbi) & 0x3f) << 7	\
 	 | ((gi) & 0x3f) << 1 | (ct))
 
+/* PD Timer definitions */
+/* tTypeCSinkWaitCap (Table 6-68 Time Values, USB PD3.1 Spec) */
+#define PD_TIMER_SINK_WAIT_CAP		0
+/* tPSSourceOff (Table 6-68 Time Values, USB PD3.1 Spec) */
+#define PD_TIMER_PS_SOURCE_OFF		1
+/* tCCDebounce (Table 4-33 CC Timing, USB Type-C Cable & Connector Spec Rel2.2) */
+#define PD_TIMER_CC_DEBOUNCE		2
+
 #endif /* __DT_POWER_DELIVERY_H */
-- 
2.46.0.598.g6f2099f65c-goog