Teach IO firmware that arming and lockdown are two different things, clean up arming check

3 files changed, 16 insertions, 8 deletions

diff --git a/src/modules/px4iofirmware/mixer.cpp b/src/modules/px4iofirmware/mixer.cpp
index e55ef784a..ea9e71c53 100644
--- a/src/modules/px4iofirmware/mixer.cpp
+++ b/src/modules/px4iofirmware/mixer.cpp
@@ -217,14 +217,25 @@ mixer_tick(void)
 		}
 	}
 
-	if ((should_arm || should_always_enable_pwm) && !mixer_servos_armed) {
+	/* set arming */
+	bool needs_to_arm = (should_arm || should_always_enable_pwm);
+
+	/* check any conditions that prevent arming */
+	if (r_setup_arming & PX4IO_P_SETUP_ARMING_LOCKDOWN) {
+		needs_to_arm = false;
+	}
+	if (!should_arm && !should_always_enable_pwm) {
+		needs_to_arm = false;
+	}
+
+	if (needs_to_arm && !mixer_servos_armed) {
 		/* need to arm, but not armed */
 		up_pwm_servo_arm(true);
 		mixer_servos_armed = true;
 		r_status_flags |= PX4IO_P_STATUS_FLAGS_OUTPUTS_ARMED;
 		isr_debug(5, "> PWM enabled");
 
-	} else if ((!should_arm && !should_always_enable_pwm) && mixer_servos_armed) {
+	} else if (!needs_to_arm && mixer_servos_armed) {
 		/* armed but need to disarm */
 		up_pwm_servo_arm(false);
 		mixer_servos_armed = false;
diff --git a/src/modules/px4iofirmware/protocol.h b/src/modules/px4iofirmware/protocol.h
index e5bef6eb3..ce8d26cc8 100644
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@@ -166,6 +166,7 @@
 #define PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK	(1 << 4) /* OK to try in-air restart */
 #define PX4IO_P_SETUP_ARMING_ALWAYS_PWM_ENABLE	(1 << 5) /* Output of PWM right after startup enabled to help ESCs initialize and prevent them from beeping */
 #define PX4IO_P_SETUP_ARMING_RC_HANDLING_DISABLED	(1 << 6) /* Disable the IO-internal evaluation of the RC */
+#define PX4IO_P_SETUP_ARMING_LOCKDOWN		(1 << 7) /* If set, the system operates normally, but won't actuate any servos */
 
 #define PX4IO_P_SETUP_PWM_RATES			2	/* bitmask, 0 = low rate, 1 = high rate */
 #define PX4IO_P_SETUP_PWM_DEFAULTRATE		3	/* 'low' PWM frame output rate in Hz */
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index ad4473073..42938b446 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -169,7 +169,8 @@ volatile uint16_t	r_page_setup[] =
 					 PX4IO_P_SETUP_ARMING_IO_ARM_OK | \
 					 PX4IO_P_SETUP_ARMING_FAILSAFE_CUSTOM | \
 					 PX4IO_P_SETUP_ARMING_ALWAYS_PWM_ENABLE | \
-					 PX4IO_P_SETUP_ARMING_RC_HANDLING_DISABLED)
+					 PX4IO_P_SETUP_ARMING_RC_HANDLING_DISABLED | \
+					 PX4IO_P_SETUP_ARMING_LOCKDOWN)
 #define PX4IO_P_SETUP_RATES_VALID	((1 << PX4IO_SERVO_COUNT) - 1)
 #define PX4IO_P_SETUP_RELAYS_VALID	((1 << PX4IO_RELAY_CHANNELS) - 1)
 
@@ -453,11 +454,6 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			 * lockup of the IO arming state.
 			 */
 
-			// XXX do not reset IO's safety state by FMU for now
-			// if ((r_setup_arming & PX4IO_P_SETUP_ARMING_FMU_ARMED) && !(value & PX4IO_P_SETUP_ARMING_FMU_ARMED)) {
-			// 	r_status_flags &= ~PX4IO_P_STATUS_FLAGS_ARMED;
-			// }
-
 			if (value & PX4IO_P_SETUP_ARMING_RC_HANDLING_DISABLED) {
 				r_status_flags |= PX4IO_P_STATUS_FLAGS_INIT_OK;
 			}