recipes-bsp: Add support for gpio-shutdown

- Feature is enabled with ENABLE_GPIO_SHUTDOWN variable
- Include the gpio-shutdown overlay
- If using SysV init include the additional keymap and inittab entries
  to bind the KEY_POWER event
- Systemd init does not require any additional bindings

Signed-off-by: Otto Esko <otto.esko@gmail.com>

recipes-bsp/bootfiles/rpi-config_git.bb

@@ -34,6 +34,8 @@ ENABLE_UART ??= ""
 
 WM8960="${@bb.utils.contains("MACHINE_FEATURES", "wm8960", "1", "0", d)}"
 
+GPIO_SHUTDOWN_PIN ??= ""
+
 inherit deploy nopackages
 
 do_deploy() {
@@ -253,6 +255,22 @@ do_deploy() {
         echo "dtoverlay=mcp2515-can0,oscillator=${CAN_OSCILLATOR},interrupt=25" >>$CONFIG
     fi
 
+
+    if [ "${ENABLE_GPIO_SHUTDOWN}" = "1" ]; then
+        if ([ "${ENABLE_I2C}" = "1" ] || [ "${PITFT}" = "1" ]) && [ -z "${GPIO_SHUTDOWN_PIN}" ]; then
+            # By default GPIO shutdown uses the same pin as the (master) I2C SCL.
+            # If I2C is configured and an alternative pin is not configured for
+            # gpio-shutdown, there is a configuration conflict.
+            bbfatal "I2C and gpio-shutdown are both enabled and using the same pins!"
+        fi
+        echo "# Enable gpio-shutdown" >> $CONFIG
+        if [ -z "${GPIO_SHUTDOWN_PIN}" ]; then
+            echo "dtoverlay=gpio-shutdown" >> $CONFIG
+        else
+            echo "dtoverlay=gpio-shutdown,gpio_pin=${GPIO_SHUTDOWN_PIN}" >> $CONFIG
+        fi
+    fi
+
     # Append extra config if the user has provided any
     printf "${RPI_EXTRA_CONFIG}\n" >> $CONFIG