diff --git a/libraries/AP_HAL_Linux/AnalogIn_ADS1115.cpp b/libraries/AP_HAL_Linux/AnalogIn_ADS1115.cpp
index e33747bb24..64f0996c1f 100644
--- a/libraries/AP_HAL_Linux/AnalogIn_ADS1115.cpp
+++ b/libraries/AP_HAL_Linux/AnalogIn_ADS1115.cpp
@@ -64,9 +64,7 @@ void AnalogIn_ADS1115::init()
 {
     _adc->init();
 
-    hal.scheduler->suspend_timer_procs();
     hal.scheduler->register_timer_process(FUNCTOR_BIND_MEMBER(&AnalogIn_ADS1115::_update, void));
-    hal.scheduler->resume_timer_procs();
 }
 
 void AnalogIn_ADS1115::_update()
diff --git a/libraries/AP_HAL_Linux/AnalogIn_IIO.cpp b/libraries/AP_HAL_Linux/AnalogIn_IIO.cpp
index f81b0fecbb..475a6ac4ec 100644
--- a/libraries/AP_HAL_Linux/AnalogIn_IIO.cpp
+++ b/libraries/AP_HAL_Linux/AnalogIn_IIO.cpp
@@ -23,6 +23,7 @@ AnalogSource_IIO::AnalogSource_IIO(int16_t pin, float initial_value, float volta
     _sum_count(0),
     _pin_fd(-1)
 {
+    _semaphore = hal.util->new_semaphore();
     init_pins();
     select_pin();
 }
@@ -50,14 +51,16 @@ void AnalogSource_IIO::select_pin(void)
 float AnalogSource_IIO::read_average()
 {
     read_latest();
-    if (_sum_count == 0) {
-        return _value;
+    if (_semaphore->take(1)) {
+        if (_sum_count == 0) {
+            _semaphore->give();
+            return _value;
+        }
+        _value = _sum_value / _sum_count;
+        _sum_value = 0;
+        _sum_count = 0;
+        _semaphore->give();
     }
-    hal.scheduler->suspend_timer_procs();
-    _value = _sum_value / _sum_count;
-    _sum_value = 0;
-    _sum_count = 0;
-    hal.scheduler->resume_timer_procs();
     return _value;
 }
 
@@ -75,9 +78,12 @@ float AnalogSource_IIO::read_latest()
         _latest = 0;
         return 0;
     }
-    _latest = atoi(sbuf) * _voltage_scaling;
-    _sum_value += _latest;
-    _sum_count++;
+    if (_semaphore->take(1)) {
+        _latest = atoi(sbuf) * _voltage_scaling;
+        _sum_value += _latest;
+        _sum_count++;
+        _semaphore->give();
+    }
 
     return _latest;
 }
@@ -100,14 +106,15 @@ void AnalogSource_IIO::set_pin(uint8_t pin)
         return;
     }
 
-    hal.scheduler->suspend_timer_procs();
-    _pin = pin;
-    _sum_value = 0;
-    _sum_count = 0;
-    _latest = 0;
-    _value = 0;
-    select_pin();
-    hal.scheduler->resume_timer_procs();
+    if (_semaphore->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
+        _pin = pin;
+        _sum_value = 0;
+        _sum_count = 0;
+        _latest = 0;
+        _value = 0;
+        select_pin();
+        _semaphore->give();
+    }
 }
 
 void AnalogSource_IIO::set_stop_pin(uint8_t p)
diff --git a/libraries/AP_HAL_Linux/AnalogIn_IIO.h b/libraries/AP_HAL_Linux/AnalogIn_IIO.h
index 790dee6670..0bce2085d4 100644
--- a/libraries/AP_HAL_Linux/AnalogIn_IIO.h
+++ b/libraries/AP_HAL_Linux/AnalogIn_IIO.h
@@ -45,6 +45,7 @@ private:
     int16_t     _pin;
     int         _pin_fd;
     int         fd_analog_sources[IIO_ANALOG_IN_COUNT];
+    AP_HAL::Semaphore *_semaphore;
 
     void init_pins(void);
     void select_pin(void);
diff --git a/libraries/AP_HAL_Linux/Scheduler.cpp b/libraries/AP_HAL_Linux/Scheduler.cpp
index f116d7fb03..2d64b46a5a 100644
--- a/libraries/AP_HAL_Linux/Scheduler.cpp
+++ b/libraries/AP_HAL_Linux/Scheduler.cpp
@@ -208,18 +208,6 @@ void Scheduler::register_timer_failsafe(AP_HAL::Proc failsafe, uint32_t period_u
     _failsafe = failsafe;
 }
 
-void Scheduler::suspend_timer_procs()
-{
-    if (!_timer_semaphore.take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-        printf("Failed to take timer semaphore\n");
-    }
-}
-
-void Scheduler::resume_timer_procs()
-{
-    _timer_semaphore.give();
-}
-
 void Scheduler::_timer_task()
 {
     int i;
@@ -229,11 +217,6 @@ void Scheduler::_timer_task()
     }
     _in_timer_proc = true;
 
-    if (!_timer_semaphore.take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-        printf("Failed to take timer semaphore in %s\n", __PRETTY_FUNCTION__);
-        return;
-    }
-
     // now call the timer based drivers
     for (i = 0; i < _num_timer_procs; i++) {
         if (_timer_proc[i]) {
@@ -241,8 +224,6 @@ void Scheduler::_timer_task()
         }
     }
 
-    _timer_semaphore.give();
-
     // and the failsafe, if one is setup
     if (_failsafe != nullptr) {
         _failsafe();
diff --git a/libraries/AP_HAL_Linux/Scheduler.h b/libraries/AP_HAL_Linux/Scheduler.h
index e340e3ded7..b44718c0f9 100644
--- a/libraries/AP_HAL_Linux/Scheduler.h
+++ b/libraries/AP_HAL_Linux/Scheduler.h
@@ -30,8 +30,6 @@ public:
 
     void     register_timer_process(AP_HAL::MemberProc);
     void     register_io_process(AP_HAL::MemberProc);
-    void     suspend_timer_procs();
-    void     resume_timer_procs();
 
     bool     in_main_thread() const override;
 
@@ -98,7 +96,6 @@ private:
     uint64_t _last_stack_debug_msec;
     pthread_t _main_ctx;
 
-    Semaphore _timer_semaphore;
     Semaphore _io_semaphore;
 };