AP_ADC: fixed thread usage in AP_ADC_ADS1115

libraries/AP_ADC/AP_ADC_ADS1115.cpp

@@ -123,12 +123,9 @@ AP_ADC_ADS1115::~AP_ADC_ADS1115()
 
 bool AP_ADC_ADS1115::init()
 {
-    hal.scheduler->suspend_timer_procs();
-
     _gain = ADS1115_PGA_4P096;
 
-    hal.scheduler->register_timer_process(FUNCTOR_BIND_MEMBER(&AP_ADC_ADS1115::_update, void));
-    hal.scheduler->resume_timer_procs();
+    _dev->register_periodic_callback(100000, FUNCTOR_BIND_MEMBER(&AP_ADC_ADS1115::_update, bool));
 
     return true;
 }
@@ -198,39 +195,25 @@ float AP_ADC_ADS1115::_convert_register_data_to_mv(int16_t word) const
     return (float) word * pga;
 }
 
-void AP_ADC_ADS1115::_update()
+bool AP_ADC_ADS1115::_update()
 {
-    /* TODO: make update rate configurable */
-    if (AP_HAL::micros() - _last_update_timestamp < 100000) {
-        return;
-    }
-
     uint8_t config[2];
     be16_t val;
 
-    if (!_dev->get_semaphore()->take_nonblocking()) {
-        return;
-    }
-
     if (!_dev->read_registers(ADS1115_RA_CONFIG, config, sizeof(config))) {
         error("_dev->read_registers failed in ADS1115");
-        _dev->get_semaphore()->give();
-        return;
+        return true;
     }
 
     /* check rdy bit */
     if ((config[1] & 0x80) != 0x80 ) {
-        _dev->get_semaphore()->give();
-        return;
+        return true;
     }
 
     if (!_dev->read_registers(ADS1115_RA_CONVERSION, (uint8_t *)&val,  sizeof(val))) {
-        _dev->get_semaphore()->give();
-        return;
+        return true;
     }
 
-    _dev->get_semaphore()->give();
-
     float sample = _convert_register_data_to_mv(be16toh(val));
 
     _samples[_channel_to_read].data = sample;
@@ -240,5 +223,5 @@ void AP_ADC_ADS1115::_update()
     _channel_to_read = (_channel_to_read + 1) % _channels_number;
     _start_conversion(_channel_to_read);
 
-    _last_update_timestamp = AP_HAL::micros();
+    return true;
 }

libraries/AP_ADC/AP_ADC_ADS1115.h

@@ -36,7 +36,7 @@ private:
     int                 _channel_to_read;
     adc_report_s        *_samples;
 
-    void _update();
+    bool _update();
     bool _start_conversion(uint8_t channel);
 
     float _convert_register_data_to_mv(int16_t word) const;