linux-kernel - [PATCH v9 05/15] dt-bindings: connector: Add property to set initial current cap for FRS

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Message-Id: <20200929024004.244992-6-badhri@google.com>
Date:   Mon, 28 Sep 2020 19:39:54 -0700
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Thierry Reding <treding@...dia.com>,
        Prashant Malani <pmalani@...omium.org>,
        Badhri Jagan Sridharan <badhri@...gle.com>
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: [PATCH v9 05/15] dt-bindings: connector: Add property to set initial
 current cap for FRS

This change adds frs-typec-current which allows setting the initial current
capability of the new source when vSafe5V is applied during PD3.0
sink Fast Role Swap.

Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
---
Changes since v1:
- Changing patch version to v6 to fix version number confusion.

Changes since v6:
- Removed the redundant usb-connector.txt that I created by mistake.
- Moved to yaml.

Changes since v7:
- Rebase 

Changes since v8:
- Redefine new-source-frs-typec-current as string enums to address
  Rob Herring's comment.
---
 .../bindings/connector/usb-connector.yaml     | 26 +++++++++++++++++++
 include/dt-bindings/usb/pd.h                  | 10 +++++++
 2 files changed, 36 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
index 9bd52e63c935..0b8cd08a8678 100644
--- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
+++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
@@ -142,6 +142,32 @@ properties:
     required:
       - port@0
 
+  new-source-frs-typec-current:
+    description: Initial current capability of the new source when vSafe5V
+      is applied during PD3.0 Fast Role Swap. "Table 6-14 Fixed Supply PDO - Sink"
+      of "USB Power Delivery Specification Revision 3.0, Version 1.2" provides the
+      different power levels and "6.4.1.3.1.6 Fast Role Swap USB Type-C Current"
+      provides a detailed description of the field. The sink PDO from current source
+      reflects the current source's(i.e. transmitter of the FRS signal) power
+      requirement during fr swap. The current sink (i.e. receiver of the FRS signal),
+      a.k.a new source, should check if it will be able to satisfy the current source's,
+      new sink's, requirement during frswap before enabling the frs signal reception.
+      This property refers to maximum current capability that the current sink can
+      satisfy. During FRS, VBUS voltage is at 5V, as the partners are in implicit
+      contract, hence, the power level is only a function of the current capability.
+      "not-supported" implies sink to source fast role swap not supported.
+      "default" refers to default USB power level as described by
+      "Table 6-14 Fixed Supply PDO - Sink".
+      "1.5A" refers to 1.5A@5V.
+      "3.0A" refers to 3.0A@5V.
+
+    $ref: /schemas/types.yaml#/definitions/string
+    enum:
+      - not-supported
+      - default
+      - 1.5A
+      - 3.0A
+
 required:
   - compatible
 
diff --git a/include/dt-bindings/usb/pd.h b/include/dt-bindings/usb/pd.h
index 985f2bbd4d24..db1ad4532197 100644
--- a/include/dt-bindings/usb/pd.h
+++ b/include/dt-bindings/usb/pd.h
@@ -35,6 +35,16 @@
 
 #define VSAFE5V 5000 /* mv units */
 
+/*
+ * Based on "Table 6-14 Fixed Supply PDO - Sink" of "USB Power Delivery Specification Revision 3.0,
+ * Version 1.2"
+ * Initial current capability of the new source when vSafe5V is applied.
+ */
+#define FRS_NOT_SUPPORTED	0
+#define FRS_DEFAULT_POWER	1
+#define FRS_5V_1P5A		2
+#define FRS_5V_3A		3
+
 #define PDO_BATT_MAX_VOLT_SHIFT	20	/* 50mV units */
 #define PDO_BATT_MIN_VOLT_SHIFT	10	/* 50mV units */
 #define PDO_BATT_MAX_PWR_SHIFT	0	/* 250mW units */
-- 
2.28.0.709.gb0816b6eb0-goog