pbio/port: Add explicit poweroff hook.

Partially implements #265

lib/pbio/include/pbio/port_interface.h

@@ -30,6 +30,10 @@
  * capabilities for a port.
  */
 typedef enum {
+    /**
+     * No mode specified.
+     */
+    PBIO_PORT_MODE_NONE = 0,
     /**
      * The port is in LEGO Powered Up mode, auto-detecting official active and
      * passive components. Runs LEGO UART Messaging protocol when a LUMP device
@@ -53,6 +57,8 @@ typedef enum {
 
 void pbio_port_init(void);
 
+bool pbio_port_poweroff_is_ready(void);
+
 void pbio_port_stop_user_actions(bool reset);
 
 pbio_error_t pbio_port_get_port(pbio_port_id_t id, pbio_port_t **port);
@@ -82,6 +88,9 @@ pbio_error_t pbio_port_set_mode(pbio_port_t *port, pbio_port_mode_t mode);
 static inline void pbio_port_init(void) {
 }
 
+static inline bool pbio_port_poweroff_is_ready(void) {
+}
+
 static inline void pbio_port_stop_user_actions(bool reset) {
 }
 

lib/pbio/src/port.c

@@ -478,6 +478,30 @@ void pbio_port_stop_user_actions(bool reset) {
     }
 }
 
+/**
+ * Prepares the system for power off by turning off all sensors and motors.
+ *
+ * @return  Whether the system is ready to power off.
+ */
+
+bool pbio_port_poweroff_is_ready(void) {
+    // Stops motors if active, ignoring sensors that need permanent power.
+    pbio_port_stop_user_actions(true);
+
+    // We also want to power off sensors that need power now and stop their
+    // processes from triggering any further actions.
+    for (uint8_t i = 0; i < PBIO_CONFIG_PORT_NUM_PORTS; i++) {
+        pbio_port_t *port = &ports[i];
+        pbio_port_set_mode(port, PBIO_PORT_MODE_NONE);
+    }
+
+    // Use ioport platform-specific needs for power off.
+    pbdrv_ioport_enable_vcc(PBDRV_IOPORT_VCC_SHUTDOWN);
+
+    // REVISIT: Test button quirk here.
+    return true;
+}
+
 void pbio_port_process_poll(void *port) {
     if (!port) {
         return;
@@ -512,6 +536,10 @@ pbio_error_t pbio_port_set_mode(pbio_port_t *port, pbio_port_mode_t mode) {
     port->mode = mode;
 
     switch (mode) {
+        case PBIO_PORT_MODE_NONE:
+            pbdrv_ioport_p5p6_set_mode(port->pdata->pins, port->uart_dev, PBDRV_IOPORT_P5P6_MODE_GPIO_ADC);
+            pbio_port_p1p2_set_power(port, PBIO_PORT_POWER_REQUIREMENTS_NONE);
+            return PBIO_SUCCESS;
         case PBIO_PORT_MODE_LEGO_PUP:
             // Physical modes for this mode will be set by the process so this
             // is all we need to do here.

lib/pbio/sys/main.c

@@ -7,10 +7,10 @@
 
 #include <stdint.h>
 
-#include <pbdrv/ioport.h>
 #include <pbdrv/reset.h>
 #include <pbdrv/usb.h>
 #include <pbio/main.h>
+#include <pbio/port_interface.h>
 #include <pbio/protocol.h>
 #include <pbsys/core.h>
 #include <pbsys/main.h>
@@ -129,8 +129,6 @@ int main(int argc, char **argv) {
     // Now lower-level processes may shutdown and/or power off.
     pbsys_status_set(PBIO_PYBRICKS_STATUS_SHUTDOWN);
 
-    pbdrv_ioport_enable_vcc(PBDRV_IOPORT_VCC_SHUTDOWN);
-
     // The power could be held on due to someone pressing the center button
     // or USB being plugged in, so we have this loop to keep pumping events
     // to turn off most of the peripherals and keep the battery charger running.
@@ -140,6 +138,12 @@ int main(int argc, char **argv) {
         while (pbio_do_one_event()) {
         }
 
+        // Prepare ports for power off but don't turn off power yet if
+        // ports are not ready.
+        if (!pbio_port_poweroff_is_ready()) {
+            continue;
+        }
+
         #if PBSYS_CONFIG_BATTERY_CHARGER
         // On hubs with USB battery chargers, we can't turn off power while
         // USB is connected, otherwise it disables the op-amp that provides