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 <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>

Documentation/devicetree/bindings/i2c/i2c-gpio.yaml

···
       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
···
     description: this means that something outside of our control has put the
       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