drv/ioport_lpf2: add move hub shutdown quirk

This adds a configuration option to handle a quirk of the BOOST Move
hub. For some reason, this hub turns back on when the power button is
released after shutdown if the port VCC is turned off.

Also added PROCESS_EXIT() to the exit handler just to be safe while we
are touching this (otherwise device connection manager might run one
more iteration).

Fixes: pybricks/support#386
Fixes: 1473c4b

CHANGELOG.md

@@ -6,7 +6,7 @@
 ## [Unreleased]
 
 ### Added
-- Added `reset_angle=False` keyword argument to `Motor()` class. 
+- Added `reset_angle=False` keyword argument to `Motor()` class.
   This makes resetting the angle optional, allowing to maintain absolute
   positioning for robots with gears ([support#389]).
 
@@ -16,6 +16,7 @@
 
 ### Fixed
 - Fixed City hub not always powering off on shutdown ([support#385]).
+- Fixed Move hub turning back on after shutdown ([support#386]).
 
 ## [3.1.0a2] - 2021-07-06
 
@@ -95,6 +96,7 @@ Prerelease changes are documented at [support#48].
 [support#361]: https://github.com/pybricks/support/issues/361
 [support#379]: https://github.com/pybricks/support/issues/379
 [support#385]: https://github.com/pybricks/support/issues/385
+[support#386]: https://github.com/pybricks/support/issues/386
 [support#389]: https://github.com/pybricks/support/issues/389
 
 [Unreleased]: https://github.com/pybricks/pybricks-micropython/compare/v3.1.0a2...HEAD

lib/pbio/drv/ioport/ioport_lpf2.c

@@ -409,8 +409,16 @@ PROCESS_THREAD(pbdrv_ioport_lpf2_process, ev, data) {
         // TODO: we need to ensure H-bridge power is off here to avoid potentially
         // damaging custom I/O devices.
 
+        #if PBDRV_CONFIG_IOPORT_LPF2_BOOST_SHUTDOWN_QUIRK
+        // The LEGO BOOST Move hub will turn right back on when the power button
+        // is released if we turn off VCC at shutdown for some reason (hardware bug?).
+        pbdrv_gpio_out_high(&pbdrv_ioport_lpf2_platform_data.port_vcc);
+        #else
         // Turn off power on pin 4 on all ports
         pbdrv_gpio_out_low(&pbdrv_ioport_lpf2_platform_data.port_vcc);
+        #endif
+
+        PROCESS_EXIT();
     });
 
     PROCESS_BEGIN();

lib/pbio/platform/move_hub/pbdrvconfig.h

@@ -41,6 +41,7 @@
 
 #define PBDRV_CONFIG_IOPORT                         (1)
 #define PBDRV_CONFIG_IOPORT_LPF2                    (1)
+#define PBDRV_CONFIG_IOPORT_LPF2_BOOST_SHUTDOWN_QUIRK (1)
 #define PBDRV_CONFIG_IOPORT_LPF2_NUM_PORTS          (2)
 #define PBDRV_CONFIG_IOPORT_LPF2_FIRST_PORT         PBIO_PORT_ID_C
 #define PBDRV_CONFIG_IOPORT_LPF2_LAST_PORT          PBIO_PORT_ID_D