i2c: sh_mobile: document support for r8a77990 (R-Car E3)

Document support for the IIC code for the r8a77990 (R-Car E3).

It is not considered compatible with existing fallback bindings
due to the documented absence of automatic transmission registers.

Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
index d81b626..bc876b7 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt
@@ -16,6 +16,7 @@ Required properties:
                        - "renesas,iic-r8a7795" (R-Car H3)
                        - "renesas,iic-r8a7796" (R-Car M3-W)
                        - "renesas,iic-r8a77965" (R-Car M3-N)
+                       - "renesas,iic-r8a77990" (R-Car E3)
                        - "renesas,iic-sh73a0" (SH-Mobile AG5)
                        - "renesas,rcar-gen2-iic" (generic R-Car Gen2 or RZ/G1
                                                        compatible device)
@@ -28,7 +29,13 @@ Required properties:
                        the platform first followed by the generic R-Car
                        version.
 
-                       renesas,rmobile-iic must always follow.
+                       When compatible with "renesas,rmobile-iic" it should
+                       be the last compatibility string listed.
+
+                       The r8a77990 (R-Car E3) controller is not
+                       considered compatible with "renesas,rcar-gen3-iic"
+                       or "renesas,rmobile-iic" due to the absence of
+                       automatic transmission registers.
 
 - reg             : address start and address range size of device
 - interrupts      : interrupt of device