overlays: mcp23017: Support the MCP23008

Add an 'mcp23008' parameter to enable support for the MCP23008 device.

See: https://github.com/raspberrypi/linux/issues/2818

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README
index 707ea49..6aa0059 100644 (file)
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -1212,6 +1212,8 @@ Params: gpiopin                 Gpio pin connected to the INTA output of the
 
         addr                    I2C address of the MCP23017 (default: 0x20)
 
+        mcp23008                Configure an MCP23008 instead.
+
 
 Name:   mcp23s17
 Info:   Configures the MCP23S08/17 SPI GPIO expanders.

diff --git a/arch/arm/boot/dts/overlays/mcp23017-overlay.dts b/arch/arm/boot/dts/overlays/mcp23017-overlay.dts
index 412f966..42f2d0f 100644 (file)
--- a/arch/arm/boot/dts/overlays/mcp23017-overlay.dts
+++ b/arch/arm/boot/dts/overlays/mcp23017-overlay.dts
@@ -44,11 +44,19 @@
                        };
                };
        };
-       
+
+       fragment@3 {
+               target = <&mcp23017>;
+               __dormant__ {
+                       compatible = "microchip,mcp23008";
+               };
+       };
+
        __overrides__ {
                gpiopin = <&mcp23017_pins>,"brcm,pins:0",
                                <&mcp23017>,"interrupts:0";
                addr = <&mcp23017>,"reg:0";
+               mcp23008 = <0>,"=3";
        };
 };