From 40609ec9a60194b9f04cf5ee4fbc4ee5a011a7ea Mon Sep 17 00:00:00 2001
From: Michael Kaplan <m.kaplan@evva.com>
Date: Tue, 24 May 2016 10:19:08 +0200
Subject: [PATCH] Added Overlay for Microchip MCP23017 I2C gpio expander

---
 arch/arm/boot/dts/overlays/README               |  9 +++++
 arch/arm/boot/dts/overlays/mcp23017-overlay.dts | 54 +++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/mcp23017-overlay.dts

--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -567,6 +567,15 @@ Params: gpio_out_pin            GPIO for
                                 (default "off")
 
 
+Name:   mcp23017
+Info:   Configures the MCP23017 I2C port expander
+Load:   dtoverlay=mcp23017,<param>=<val>
+Params: gpiopin                 Gpio pin connected to the INTA output of the
+                                MCP23017 (default: 4)
+
+        addr                    I2C address of the MCP23017 (default: 0x20)
+
+
 Name:   mcp2515-can0
 Info:   Configures the MCP2515 CAN controller on spi0.0
 Load:   dtoverlay=mcp2515-can0,<param>=<val>
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/mcp23017-overlay.dts
@@ -0,0 +1,54 @@
+// Definitions for MCP23017 Gpio Extender from Microchip Semiconductor
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&i2c1>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target = <&gpio>;
+		__overlay__ {
+			mcp23017_pins: mcp23017_pins {
+				brcm,pins = <4>;
+				brcm,function = <0>;
+			};
+		};
+	};
+
+	fragment@2 {
+		target = <&i2c1>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			mcp23017: mcp@20 {
+				compatible = "microchip,mcp23017";
+				reg = <0x20>;
+				gpio-controller;
+				#gpio-cells = <2>;
+				#interrupt-cells=<2>;
+				interrupt-parent = <&gpio>;
+				interrupts = <4 2>;
+				interrupt-controller;
+				microchip,irq-mirror;
+
+				status = "okay";
+			};
+		};
+	};
+	
+	__overrides__ {
+		gpiopin = <&mcp23017_pins>,"brcm,pins:0",
+				<&mcp23017>,"interrupts:0";
+		addr = <&mcp23017>,"reg:0";
+	};
+};
+