Interfaces.md

@@ -337,6 +337,12 @@ access to GPIO hardware.
 
     * number (slot): GPIO pin number to export and expose to consuming snaps
 
+Snaps that want to consume a gpio device simply `plugs: [ gpio ]` and the gpio
+device to connect is specified during interface connection. Available gpio
+devices for the system can be seen with `snap interfaces`. Once connected,
+the consuming snap can use the device via `/sys/class/gpio/gpioN` where `N` is
+the pin number specified by the connected slot.
+
 ### hardware-observe
 
 Can query hardware information from the system.
@@ -362,6 +368,12 @@ access to hardware devices.
     * path (slot): path where a symlink will be created to the device
     e.g. /dev/hidraw-mydevice
 
+Snaps that want to consume a hidraw device simply `plugs: [ hidraw ]` and
+the hidraw device to connect is specified during interface connection. Available
+hidraw devices for the system can be seen with `snap interfaces`. Once connected,
+the consuming snap can use the device via the path specified by the connected
+slot.
+
 ### i2c
 
 Can access i2c devices. This is restricted because it provides privileged
@@ -372,6 +384,12 @@ access to hardware devices.
 
     * path (slot): path to i2c device node e.g. /dev/i2c-0
 
+Snaps that want to consume an i2c device simply `plugs: [ i2c ]` and the i2c
+device to connect is specified during interface connection. Available i2c
+devices for the system can be seen with `snap interfaces`. Once connected,
+the consuming snap can use the device via the path specified by the connected
+slot.
+
 ### kernel-module-control
 
 Can insert kernel modules. This interface gives privileged access to the device.
@@ -522,6 +540,12 @@ access to configure serial port hardware.
     * path (slot): path where a symlink will be created to the device
     e.g. /dev/serial-port-mydevice
 
+Snaps that want to consume a serial port simply `plugs: [ serial-port ]` and
+the serial port to connect is specified during interface connection. Available
+serial ports for the system can be seen with `snap interfaces`. Once connected,
+the consuming snap can use the device via the path specified by the connected
+slot.
+
 ### snapd-control
 
 Can manage snaps via snapd.