fix(mixer_module): change MixingOutput to use float outputs (#26724)

* refactor(mixer_module): change MixingOutput to use float outputs

MixingOutput now passes float values to output drivers instead of
uint16_t. This removes the need for the 8192 offset encoding and
allows reversible motors to receive negative values directly.

* fix(mixer_module): fix float safety issues

-EscClient and voxl2_io: replace outputs[i] with fabs(outputs[i]) > 0.fto fix compilation issues
-GZMixingInterface: add explicit double cast to prevent compilation error
-PWMSim: replaced unit16 cast with lroundf given that now motors outputs can be negative and casting a negative float to unit16 is undefinder behaviour
-mixer_module: same fix of PWM (unit126 cast on negative float is undefined behaviour)

* refactor(mixer_module): float rounding suggestions

* fix(pwm_sim): fix inverted disarmed condition

* fix(mixer_module): more float rounding improvements

* fix(mixer_module_tests): use casting method which are now in drivers for rounding tests

---------

Co-authored-by: Matthias Grob <maetugr@gmail.com>

src/drivers/linux_pwm_out/linux_pwm_out.cpp

@@ -97,10 +97,15 @@ int LinuxPWMOut::task_spawn(int argc, char *argv[])
 	return PX4_ERROR;
 }
 
-bool LinuxPWMOut::updateOutputs(uint16_t outputs[MAX_ACTUATORS],
-				unsigned num_outputs, unsigned num_control_groups_updated)
+bool LinuxPWMOut::updateOutputs(float outputs[MAX_ACTUATORS], unsigned num_outputs, unsigned num_control_groups_updated)
 {
-	_pwm_out->send_output_pwm(outputs, num_outputs);
+	uint16_t hw_outputs[MAX_ACTUATORS] {};
+
+	for (unsigned i = 0; i < num_outputs; i++) {
+		hw_outputs[i] = static_cast<uint16_t>(lroundf(outputs[i]));
+	}
+
+	_pwm_out->send_output_pwm(hw_outputs, num_outputs);
 	return true;
 }
 

src/drivers/linux_pwm_out/linux_pwm_out.hpp

@@ -73,8 +73,7 @@ public:
 
 	int init();
 
-	bool updateOutputs(uint16_t outputs[MAX_ACTUATORS],
-			   unsigned num_outputs, unsigned num_control_groups_updated) override;
+	bool updateOutputs(float outputs[MAX_ACTUATORS], unsigned num_outputs, unsigned num_control_groups_updated) override;
 
 private:
 	static constexpr int MAX_ACTUATORS = 8;