ARM: sunxi: add support for R40 SoC

Allwinner R40 is a new SoC, with Quad Core Cortex-A7 and peripherals
like A20.

Add support for it.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.io>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Documentation/arm/sunxi/README

@@ -76,6 +76,12 @@ SunXi family
         + Datasheet
           http://dl.linux-sunxi.org/H3/Allwinner_H3_Datasheet_V1.0.pdf
 
+      - Allwinner R40 (sun8i)
+        + Datasheet
+          https://github.com/tinalinux/docs/raw/r40-v1.y/R40_Datasheet_V1.0.pdf
+        + User Manual
+          https://github.com/tinalinux/docs/raw/r40-v1.y/Allwinner_R40_User_Manual_V1.0.pdf
+
     * Quad ARM Cortex-A15, Quad ARM Cortex-A7 based SoCs
       - Allwinner A80
         + Datasheet

Documentation/devicetree/bindings/arm/sunxi.txt

@@ -14,6 +14,7 @@ using one of the following compatible strings:
   allwinner,sun8i-a83t
   allwinner,sun8i-h2-plus
   allwinner,sun8i-h3
+  allwinner-sun8i-r40
   allwinner,sun8i-v3s
   allwinner,sun9i-a80
   allwinner,sun50i-a64

arch/arm/mach-sunxi/sunxi.c

@@ -65,6 +65,7 @@ static const char * const sun8i_board_dt_compat[] = {
 	"allwinner,sun8i-a83t",
 	"allwinner,sun8i-h2-plus",
 	"allwinner,sun8i-h3",
+	"allwinner,sun8i-r40",
 	"allwinner,sun8i-v3s",
 	NULL,
 };