dt-bindings: i2c: gpio: Add properties for dealing with write-only SDA/SCL w/o pullup

There are slave devices that understand I2C but have read-only SDA and
SCL. Examples are FD650 7-segment LED controller and its derivatives.
Typical board designs don't even have a pull-up for both pins.
Therefore add properties for not using open-drain. For write-only SCL
we have a property already, add one for write-only SDA.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
index e0d76d5..afd4925 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
+++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml
@@ -33,6 +33,10 @@ properties:
       open drain.
     maxItems: 1
 
+  i2c-gpio,sda-output-only:
+    description: sda as output only
+    type: boolean
+
   i2c-gpio,scl-output-only:
     description: scl as output only
     type: boolean
@@ -63,6 +67,28 @@ properties:
       GPIO line used for SCL into open drain mode, and that something is not
       the GPIO chip. It is essentially an inconsistency flag.
 
+  i2c-gpio,sda-has-no-pullup:
+    type: boolean
+    description: sda is used in a non-compliant way and has no pull-up.
+      Therefore disable open-drain. This property is mutually-exclusive
+      with i2c-gpio,sda-open-drain.
+
+  i2c-gpio,scl-has-no-pullup:
+    type: boolean
+    description: scl is used in a non-compliant way and has no pull-up.
+      Therefore disable open-drain. This property is mutually-exclusive
+      with i2c-gpio,scl-open-drain.
+
+dependencies:
+  i2c-gpio,sda-has-no-pullup:
+    not:
+      required:
+        - i2c-gpio,sda-open-drain
+  i2c-gpio,scl-has-no-pullup:
+    not:
+      required:
+        - i2c-gpio,scl-open-drain
+
 required:
   - compatible
   - sda-gpios