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Date:   Tue, 20 Oct 2020 02:36:18 -0700
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Subject: [PATCH v11 01/10] dt-bindings: connector: Add property to set initial
 current cap for FRS
From:   Badhri Jagan Sridharan <badhri@google.com>
To:     Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Lee Jones <lee.jones@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Maxime Ripard <mripard@kernel.org>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Thierry Reding <treding@nvidia.com>,
        Prashant Malani <pmalani@chromium.org>,
        Badhri Jagan Sridharan <badhri@google.com>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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@google.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.

Changes since v9:
- Removed FRS constants from usb bindings.

Changes since v10:
- Suggestions from Rob Herring:
 - Going back to u32 for new-source-frs-typec-current
 - Removed the definition for "not-supported"
- Bringing back FRS constants for usb pd binding.
---
 .../bindings/connector/usb-connector.yaml     | 19 +++++++++++++++++++
 include/dt-bindings/usb/pd.h                  |  8 ++++++++
 2 files changed, 27 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/usb-connector.yaml b/Documentation/devicetree/bindings/connector/usb-connector.yaml
index 728f82db073d..62781518aefc 100644
--- a/Documentation/devicetree/bindings/connector/usb-connector.yaml
+++ b/Documentation/devicetree/bindings/connector/usb-connector.yaml
@@ -147,6 +147,25 @@ 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.
+      "1" refers to default USB power level as described by "Table 6-14 Fixed Supply PDO - Sink".
+      "2" refers to 1.5A@5V.
+      "3" refers to 3.0A@5V.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [1, 2, 3]
+
 required:
   - compatible
 
diff --git a/include/dt-bindings/usb/pd.h b/include/dt-bindings/usb/pd.h
index 985f2bbd4d24..0352893697f0 100644
--- a/include/dt-bindings/usb/pd.h
+++ b/include/dt-bindings/usb/pd.h
@@ -85,4 +85,12 @@
 	 PDO_PPS_APDO_MIN_VOLT(min_mv) | PDO_PPS_APDO_MAX_VOLT(max_mv) |	\
 	 PDO_PPS_APDO_MAX_CURR(max_ma))
 
+ /*
+  * 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_DEFAULT_POWER      1
+#define FRS_5V_1P5A            2
+#define FRS_5V_3A              3
  #endif /* __DT_POWER_DELIVERY_H */
-- 
2.29.0.rc1.297.gfa9743e501-goog