PWM automatic trigger system (ATS) for parachutes (#13726)

* parameter and logic to commander for triggering failsafe from external automatic trigger system.
* logic to startup script for enabling ATS. Added uORB publishing to pwm_input module.
* Refactored out CDev usage from pwm_input and ll40ls. Refactored out ll40ls specifics from pwm_input and cleaned up dead code.

src/drivers/distance_sensor/ll40ls/LidarLitePWM.cpp

@@ -44,10 +44,13 @@
 
 #include "LidarLitePWM.h"
 
+#ifdef LIDAR_LITE_PWM_SUPPORTED
+
 LidarLitePWM::LidarLitePWM(const uint8_t rotation) :
 	LidarLite(rotation),
 	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::hp_default)
 {
+	px4_arch_configgpio(GPIO_VDD_RANGEFINDER_EN);
 }
 
 LidarLitePWM::~LidarLitePWM()
@@ -113,17 +116,16 @@ LidarLitePWM::measure()
 int
 LidarLitePWM::collect()
 {
-	int fd = ::open(PWMIN0_DEVICE_PATH, O_RDONLY);
+	pwm_input_s pwm_input;
 
-	if (fd == -1) {
-		return PX4_ERROR;
-	}
+	if (_sub_pwm_input.update(&pwm_input)) {
+
+		_pwm = pwm_input;
 
-	if (::read(fd, &_pwm, sizeof(_pwm)) == sizeof(_pwm)) {
-		::close(fd);
 		return PX4_OK;
 	}
 
-	::close(fd);
 	return EAGAIN;
 }
+
+#endif

src/drivers/distance_sensor/ll40ls/LidarLitePWM.h

@@ -45,14 +45,15 @@
 
 #include "LidarLite.h"
 
-#include <stdio.h>
-#include <string.h>
-
-#include <drivers/drv_hrt.h>
-#include <drivers/drv_pwm_input.h>
-#include <px4_platform_common/defines.h>
 #include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
+
 #include <uORB/topics/pwm_input.h>
+#include <uORB/Subscription.hpp>
+
+#ifdef GPIO_GPIO5_OUTPUT
+
+#define LIDAR_LITE_PWM_SUPPORTED
+#define GPIO_VDD_RANGEFINDER_EN GPIO_GPIO5_OUTPUT
 
 class LidarLitePWM : public LidarLite, public px4::ScheduledWorkItem
 {
@@ -73,7 +74,9 @@ protected:
 
 private:
 
-	int _pwmSub{-1};
+	uORB::Subscription _sub_pwm_input{ORB_ID(pwm_input)};
 
 	pwm_input_s _pwm{};
 };
+
+#endif

src/drivers/distance_sensor/ll40ls/ll40ls.cpp

@@ -164,7 +164,12 @@ start_pwm(const uint8_t rotation)
 		return PX4_OK;
 	}
 
+#ifdef LIDAR_LITE_PWM_SUPPORTED
 	instance = new LidarLitePWM(rotation);
+#else
+	instance = nullptr;
+	PX4_ERR("PWM input not supported.");
+#endif
 
 	if (instance == nullptr) {
 		PX4_ERR("Failed to instantiate the driver");