diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_Bebop.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_Bebop.cpp
index d85c988276..2ad13d988a 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_Bebop.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_Bebop.cpp
@@ -24,11 +24,14 @@
 #include <AP_HAL_Linux/RCOutput_Bebop.h>
 #include <AP_HAL_Linux/RCOutput_Disco.h>
 
-extern const AP_HAL::HAL& hal;
-
 #define BATTERY_CAPACITY (1200U) /* mAh */
 #define BATTERY_VOLTAGE_COMPENSATION_LANDED (0.2f)
 
+
+extern const AP_HAL::HAL &hal;
+
+using namespace Linux;
+
 /* polynomial compensation coefficients */
 static const float bat_comp_polynomial_coeffs[5] = {
     -1.2471059149657287e-16f,
diff --git a/libraries/AP_HAL_Linux/AP_HAL_Linux_Namespace.h b/libraries/AP_HAL_Linux/AP_HAL_Linux_Namespace.h
deleted file mode 100644
index afe6b9797c..0000000000
--- a/libraries/AP_HAL_Linux/AP_HAL_Linux_Namespace.h
+++ /dev/null
@@ -1,56 +0,0 @@
-#pragma once
-
-namespace Linux {
-    class UARTDriver;
-    class SPIUARTDriver;
-    class RPIOUARTDriver;
-    class I2CDevice;
-    class I2CDeviceManager;
-    class SPIDeviceManager;
-    class SPIDeviceDriver;
-    class Storage;
-    class GPIO_BBB;
-    class GPIO_RPI;
-    class GPIO_Sysfs;
-    class Storage;
-    class DigitalSource;
-    class DigitalSource_Sysfs;
-    class PeriodicThread;
-    class PWM_Sysfs;
-    class PWM_Sysfs_Bebop;
-    class PWM_Sysfs_Base;
-    class RCInput;
-    class RCInput_PRU;
-    class RCInput_AioPRU;
-    class RCInput_RPI;
-    class RCInput_Raspilot;
-    class RCInput_Navio2;
-    class RCInput_ZYNQ;
-    class RCInput_UART;
-    class RCInput_UDP;
-    class RCInput_DSM;
-    class RCInput_SBUS;
-    class RCOutput_PRU;
-    class RCOutput_AioPRU;
-    class RCOutput_PCA9685;
-    class RCOutput_Raspilot;
-    class RCOutput_ZYNQ;
-    class RCOutput_Bebop;
-    class RCOutput_Sysfs;
-    class RCOutput_QFLIGHT;
-    class RCOutput_Disco;
-    class Semaphore;
-    class Scheduler;
-    class Util;
-    class UtilRPI;
-    class ToneAlarm;
-    class ToneAlarm_Raspilot;
-    class Thread;
-    class Heat;
-    class HeatPwm;
-    class CameraSensor;
-    class CameraSensor_Mt9v117;
-    class VideoIn;
-    class OpticalFlow_Onboard;
-    class Flow_PX4;
-}
diff --git a/libraries/AP_HAL_Linux/CameraSensor.h b/libraries/AP_HAL_Linux/CameraSensor.h
index f5858aa8a0..3fd0861f8d 100644
--- a/libraries/AP_HAL_Linux/CameraSensor.h
+++ b/libraries/AP_HAL_Linux/CameraSensor.h
@@ -16,7 +16,9 @@
 
 #include "AP_HAL_Linux.h"
 
-class Linux::CameraSensor {
+namespace Linux {
+
+class CameraSensor {
 public:
     CameraSensor(const char *device_path) { _device_path = device_path; }
 
@@ -26,3 +28,5 @@ public:
 private:
     const char *_device_path;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Flow_PX4.h b/libraries/AP_HAL_Linux/Flow_PX4.h
index fe5ec728f6..1c5b763045 100644
--- a/libraries/AP_HAL_Linux/Flow_PX4.h
+++ b/libraries/AP_HAL_Linux/Flow_PX4.h
@@ -16,7 +16,9 @@
 
 #include "AP_HAL_Linux.h"
 
-class Linux::Flow_PX4 {
+namespace Linux {
+
+class Flow_PX4 {
 public:
     Flow_PX4(uint32_t width, uint32_t bytesperline,
              uint32_t max_flow_pixel,
@@ -35,3 +37,5 @@ private:
     uint16_t _pixstep;
     uint8_t  _num_blocks;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/GPIO.h b/libraries/AP_HAL_Linux/GPIO.h
index c7d079f598..0c8aa85d32 100644
--- a/libraries/AP_HAL_Linux/GPIO.h
+++ b/libraries/AP_HAL_Linux/GPIO.h
@@ -2,7 +2,9 @@
 
 #include "AP_HAL_Linux.h"
 
-class Linux::DigitalSource : public AP_HAL::DigitalSource {
+namespace Linux {
+
+class DigitalSource : public AP_HAL::DigitalSource {
 public:
     DigitalSource(uint8_t v);
     void    mode(uint8_t output);
@@ -14,6 +16,8 @@ private:
 
 };
 
+}
+
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_PXF || CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_ERLEBOARD || CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BBBMINI
 #include "GPIO_BBB.h"
 #elif CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_NAVIO || \
diff --git a/libraries/AP_HAL_Linux/GPIO_BBB.h b/libraries/AP_HAL_Linux/GPIO_BBB.h
index 90ec8aa260..df07da8abb 100644
--- a/libraries/AP_HAL_Linux/GPIO_BBB.h
+++ b/libraries/AP_HAL_Linux/GPIO_BBB.h
@@ -103,7 +103,9 @@
 #define BBB_P9_41 20
 #define BBB_P9_42 7
 
-class Linux::GPIO_BBB : public AP_HAL::GPIO {
+namespace Linux {
+
+class GPIO_BBB : public AP_HAL::GPIO {
 private:
     struct GPIO {
         volatile uint32_t *base;
@@ -131,3 +133,5 @@ public:
     /* return true if USB cable is connected */
     bool    usb_connected(void);
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/GPIO_RPI.h b/libraries/AP_HAL_Linux/GPIO_RPI.h
index 91ef542496..59dc3ae808 100644
--- a/libraries/AP_HAL_Linux/GPIO_RPI.h
+++ b/libraries/AP_HAL_Linux/GPIO_RPI.h
@@ -41,7 +41,9 @@
 #define RPI_GPIO_30   30   // Pin 5
 #define RPI_GPIO_31   31   // Pin 6
 
-class Linux::GPIO_RPI : public AP_HAL::GPIO {
+namespace Linux {
+
+class GPIO_RPI : public AP_HAL::GPIO {
 public:
     GPIO_RPI();
     void    init();
@@ -65,3 +67,5 @@ public:
 private:
     volatile uint32_t *_gpio;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/GPIO_Sysfs.h b/libraries/AP_HAL_Linux/GPIO_Sysfs.h
index f42cb1f19f..46bcc7ef89 100644
--- a/libraries/AP_HAL_Linux/GPIO_Sysfs.h
+++ b/libraries/AP_HAL_Linux/GPIO_Sysfs.h
@@ -5,8 +5,10 @@
 
 #include "GPIO.h"
 
-class Linux::DigitalSource_Sysfs : public AP_HAL::DigitalSource {
-    friend class Linux::GPIO_Sysfs;
+namespace Linux {
+
+class DigitalSource_Sysfs : public AP_HAL::DigitalSource {
+    friend class GPIO_Sysfs;
 public:
     ~DigitalSource_Sysfs();
     uint8_t read();
@@ -23,8 +25,8 @@ private:
 /**
  * Generic implementation of AP_HAL::GPIO for Linux based boards.
  */
-class Linux::GPIO_Sysfs : public AP_HAL::GPIO {
-    friend class Linux::DigitalSource_Sysfs;
+class GPIO_Sysfs : public AP_HAL::GPIO {
+    friend class DigitalSource_Sysfs;
 public:
     /* Fill this table with the real pin numbers. */
     static const unsigned pin_table[];
@@ -76,3 +78,5 @@ protected:
      */
     static bool _export_pin(uint8_t vpin);
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/HAL_Linux_Class.h b/libraries/AP_HAL_Linux/HAL_Linux_Class.h
index 351ae78e3c..9aa95ddc86 100644
--- a/libraries/AP_HAL_Linux/HAL_Linux_Class.h
+++ b/libraries/AP_HAL_Linux/HAL_Linux_Class.h
@@ -2,8 +2,6 @@
 
 #include <AP_HAL/AP_HAL.h>
 
-#include "AP_HAL_Linux_Namespace.h"
-
 class HAL_Linux : public AP_HAL::HAL {
 public:
     HAL_Linux();
diff --git a/libraries/AP_HAL_Linux/Heat.h b/libraries/AP_HAL_Linux/Heat.h
index adc7b4dee7..d765b74ffa 100644
--- a/libraries/AP_HAL_Linux/Heat.h
+++ b/libraries/AP_HAL_Linux/Heat.h
@@ -15,8 +15,12 @@
  */
 #pragma once
 
-class Linux::Heat {
+namespace Linux {
+
+class Heat {
 public:
     virtual void set_imu_temp(float current) { }
     virtual void set_imu_target_temp(int8_t *target) { }
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Heat_Pwm.h b/libraries/AP_HAL_Linux/Heat_Pwm.h
index 18bf5ee567..6c8d559392 100644
--- a/libraries/AP_HAL_Linux/Heat_Pwm.h
+++ b/libraries/AP_HAL_Linux/Heat_Pwm.h
@@ -19,7 +19,9 @@
 #include "PWM_Sysfs.h"
 #include "Heat.h"
 
-class Linux::HeatPwm : public Linux::Heat {
+namespace Linux {
+
+class HeatPwm : public Heat {
 public:
     HeatPwm(uint8_t pwm_num, float Kp, float Ki,
             uint32_t period_ns);
@@ -35,3 +37,5 @@ private:
     float _sum_error;
     int8_t *_target = nullptr;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/OpticalFlow_Onboard.h b/libraries/AP_HAL_Linux/OpticalFlow_Onboard.h
index 7f17f04f56..9d18d8cf78 100644
--- a/libraries/AP_HAL_Linux/OpticalFlow_Onboard.h
+++ b/libraries/AP_HAL_Linux/OpticalFlow_Onboard.h
@@ -22,9 +22,12 @@
 #include "AP_HAL_Linux.h"
 #include "CameraSensor.h"
 #include "Flow_PX4.h"
+#include "PWM_Sysfs.h"
 #include "VideoIn.h"
 
-class Linux::OpticalFlow_Onboard : public AP_HAL::OpticalFlow {
+namespace Linux {
+
+class OpticalFlow_Onboard : public AP_HAL::OpticalFlow {
 public:
     void init(AP_HAL::OpticalFlow::Gyro_Cb);
     bool read(AP_HAL::OpticalFlow::Data_Frame& frame);
@@ -59,3 +62,5 @@ private:
     AP_HAL::OpticalFlow::Gyro_Cb _get_gyro;
     Vector3f _last_gyro_rate;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/PWM_Sysfs.h b/libraries/AP_HAL_Linux/PWM_Sysfs.h
index b3c6bb22fe..07bd02838a 100644
--- a/libraries/AP_HAL_Linux/PWM_Sysfs.h
+++ b/libraries/AP_HAL_Linux/PWM_Sysfs.h
@@ -5,7 +5,9 @@
 #include "AP_HAL_Linux.h"
 #include "Util.h"
 
-class Linux::PWM_Sysfs_Base {
+namespace Linux {
+
+class PWM_Sysfs_Base {
 public:
     virtual ~PWM_Sysfs_Base();
 
@@ -51,7 +53,7 @@ private:
     char *_period_path = NULL;
 };
 
-class Linux::PWM_Sysfs : public Linux::PWM_Sysfs_Base {
+class PWM_Sysfs : public PWM_Sysfs_Base {
 public:
     PWM_Sysfs(uint8_t chip, uint8_t channel);
 
@@ -63,7 +65,7 @@ private:
     char *_generate_period_path(uint8_t chip, uint8_t channel);
 };
 
-class Linux::PWM_Sysfs_Bebop : public Linux::PWM_Sysfs_Base {
+class PWM_Sysfs_Bebop : public PWM_Sysfs_Base {
 public:
     PWM_Sysfs_Bebop(uint8_t channel);
 
@@ -81,3 +83,5 @@ private:
         return PWM_Sysfs::NORMAL;
     }
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput.h b/libraries/AP_HAL_Linux/RCInput.h
index bdd22aa03a..c7e4c68583 100644
--- a/libraries/AP_HAL_Linux/RCInput.h
+++ b/libraries/AP_HAL_Linux/RCInput.h
@@ -4,7 +4,9 @@
 
 #define LINUX_RC_INPUT_NUM_CHANNELS 16
 
-class Linux::RCInput : public AP_HAL::RCInput {
+namespace Linux {
+
+class RCInput : public AP_HAL::RCInput {
 public:
     RCInput();
 
@@ -31,8 +33,8 @@ public:
 
     // add some SBUS input bytes, for RCInput over a serial port
     void add_sbus_input(const uint8_t *bytes, size_t nbytes);
-    
-    
+
+
  protected:
     void _process_rc_pulse(uint16_t width_s0, uint16_t width_s1);
     void _update_periods(uint16_t *periods, uint8_t len);
@@ -40,7 +42,7 @@ public:
  private:
     volatile bool new_rc_input;
 
-    uint16_t _pwm_values[LINUX_RC_INPUT_NUM_CHANNELS];    
+    uint16_t _pwm_values[LINUX_RC_INPUT_NUM_CHANNELS];
     uint8_t  _num_channels;
 
     void _process_ppmsum_pulse(uint16_t width);
@@ -83,5 +85,4 @@ public:
     } sbus;
 };
 
-#include "RCInput_PRU.h"
-#include "RCInput_ZYNQ.h"
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_AioPRU.h b/libraries/AP_HAL_Linux/RCInput_AioPRU.h
index 9c684b76b0..00eba5b78e 100644
--- a/libraries/AP_HAL_Linux/RCInput_AioPRU.h
+++ b/libraries/AP_HAL_Linux/RCInput_AioPRU.h
@@ -18,16 +18,18 @@
 #include "AP_HAL_Linux.h"
 
 #define RCIN_PRUSS_RAM_BASE   0x4a303000
+
 // we use 300 ring buffer entries to guarantee that a full 25 byte
 // frame of 12 bits per byte
 
-class Linux::RCInput_AioPRU : public Linux::RCInput
-{
+namespace Linux {
+
+class RCInput_AioPRU : public RCInput {
 public:
     void init();
     void _timer_tick(void);
 
- private:
+private:
     static const uint32_t TICK_PER_US = 200;
     static const uint32_t NUM_RING_ENTRIES = 300;
     // shared ring buffer with the PRU which records pin transitions
@@ -41,3 +43,5 @@ public:
     };
     volatile struct ring_buffer *ring_buffer;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_DSM.h b/libraries/AP_HAL_Linux/RCInput_DSM.h
index 3aa0de9a3b..f84e82f713 100644
--- a/libraries/AP_HAL_Linux/RCInput_DSM.h
+++ b/libraries/AP_HAL_Linux/RCInput_DSM.h
@@ -16,12 +16,15 @@
 #pragma once
 
 #include <AP_HAL/AP_HAL.h>
+
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_QFLIGHT
 
 #include "RCInput.h"
 #include "RCInput_DSM.h"
 
-class Linux::RCInput_DSM : public Linux::RCInput
+namespace Linux {
+
+class RCInput_DSM : public RCInput
 {
 public:
     void init() override;
@@ -32,5 +35,7 @@ private:
     const char *device_path;
     int32_t fd = -1;
 };
-#endif // CONFIG_HAL_BOARD_SUBTYPE
 
+}
+
+#endif // CONFIG_HAL_BOARD_SUBTYPE
diff --git a/libraries/AP_HAL_Linux/RCInput_Navio2.h b/libraries/AP_HAL_Linux/RCInput_Navio2.h
index 235a852e50..d30362edc4 100644
--- a/libraries/AP_HAL_Linux/RCInput_Navio2.h
+++ b/libraries/AP_HAL_Linux/RCInput_Navio2.h
@@ -2,8 +2,10 @@
 
 #include "RCInput.h"
 
-class Linux::RCInput_Navio2 : public Linux::RCInput
-{
+
+namespace Linux {
+
+class RCInput_Navio2 : public RCInput {
 public:
     void init() override;
     void _timer_tick(void) override;
@@ -18,3 +20,5 @@ private:
     int channels[CHANNEL_COUNT];
     uint16_t periods[ARRAY_SIZE(channels)] = {0};
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_PRU.cpp b/libraries/AP_HAL_Linux/RCInput_PRU.cpp
index 00e6cf6816..bc2b4e5f76 100644
--- a/libraries/AP_HAL_Linux/RCInput_PRU.cpp
+++ b/libraries/AP_HAL_Linux/RCInput_PRU.cpp
@@ -3,6 +3,7 @@
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_PXF || \
     CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_ERLEBOARD || \
     CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BBBMINI
+#include "RCInput_PRU.h"
 
 #include <errno.h>
 #include <fcntl.h>
diff --git a/libraries/AP_HAL_Linux/RCInput_PRU.h b/libraries/AP_HAL_Linux/RCInput_PRU.h
index b3f98acf9e..cde3e9e93d 100644
--- a/libraries/AP_HAL_Linux/RCInput_PRU.h
+++ b/libraries/AP_HAL_Linux/RCInput_PRU.h
@@ -5,14 +5,15 @@
   doing the edge detection of the PPM sum input
  */
 
-#include "AP_HAL_Linux.h"
+#include "RCInput.h"
 
 #define RCIN_PRUSS_SHAREDRAM_BASE   0x4a312000
 // we use 300 ring buffer entries to guarantee that a full 25 byte
 // frame of 12 bits per byte
 
-class Linux::RCInput_PRU : public Linux::RCInput
-{
+namespace Linux {
+
+class RCInput_PRU : public RCInput {
 public:
     void init();
     void _timer_tick(void);
@@ -33,3 +34,5 @@ public:
     // time spent in the low state
     uint16_t _s0_time;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_RPI.h b/libraries/AP_HAL_Linux/RCInput_RPI.h
index 0724491ad4..c571e66a85 100644
--- a/libraries/AP_HAL_Linux/RCInput_RPI.h
+++ b/libraries/AP_HAL_Linux/RCInput_RPI.h
@@ -22,13 +22,14 @@
 #include <queue>
 
 
+namespace Linux {
+
 enum state_t{
     RCIN_RPI_INITIAL_STATE = -1,
     RCIN_RPI_ZERO_STATE = 0,
     RCIN_RPI_ONE_STATE = 1
 };
 
-
 //Memory table structure
 typedef struct {
     void **virt_pages;
@@ -45,8 +46,8 @@ typedef struct {
 
 class Memory_table {
 // Allow RCInput_RPI access to private members of Memory_table
-friend class Linux::RCInput_RPI;
-  
+friend class RCInput_RPI;
+
 private:
     void** _virt_pages;
     void** _phys_pages;
@@ -73,14 +74,14 @@ public:
 };
 
 
-class Linux::RCInput_RPI : public Linux::RCInput
-{ 
+class RCInput_RPI : public RCInput
+{
 public:
     void init();
     void _timer_tick(void);
     RCInput_RPI();
     ~RCInput_RPI();
-    
+
 private:
 
     //Physical adresses of peripherals. Are different on different Raspberries.
@@ -110,10 +111,10 @@ private:
 
     uint8_t curr_signal;
     uint8_t last_signal;
-  
+
     state_t state;
-    
-    AP_HAL::DigitalSource *enable_pin; 
+
+    AP_HAL::DigitalSource *enable_pin;
 
     void init_dma_cb(dma_cb_t** cbp, uint32_t mode, uint32_t source, uint32_t dest, uint32_t length, uint32_t stride, uint32_t next_cb);
     void* map_peripheral(uint32_t base, uint32_t len);
@@ -127,5 +128,6 @@ private:
     void set_sigaction();
     void set_physical_addresses(int version);
     void deinit() override;
-
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_Raspilot.h b/libraries/AP_HAL_Linux/RCInput_Raspilot.h
index f967ab3b4a..1ee04b3f06 100644
--- a/libraries/AP_HAL_Linux/RCInput_Raspilot.h
+++ b/libraries/AP_HAL_Linux/RCInput_Raspilot.h
@@ -4,15 +4,20 @@
 #include "RCInput.h"
 #include <AP_HAL/SPIDevice.h>
 
-class Linux::RCInput_Raspilot : public Linux::RCInput
+
+namespace Linux {
+
+class RCInput_Raspilot : public RCInput
 {
 public:
     void init();
-    
+
 private:
     uint32_t _last_timer;
-    
+
     AP_HAL::OwnPtr<AP_HAL::SPIDevice> _dev;
-    
+
     void _poll_data(void);
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_SBUS.h b/libraries/AP_HAL_Linux/RCInput_SBUS.h
index 1d9dfad45f..b8ab1e153f 100644
--- a/libraries/AP_HAL_Linux/RCInput_SBUS.h
+++ b/libraries/AP_HAL_Linux/RCInput_SBUS.h
@@ -21,7 +21,9 @@
 #include "RCInput.h"
 #include "RCInput_SBUS.h"
 
-class Linux::RCInput_SBUS : public Linux::RCInput
+namespace Linux {
+
+class RCInput_SBUS : public RCInput
 {
 public:
     void init() override;
@@ -32,4 +34,7 @@ private:
     const char *device_path = "/dev/uart-sbus";
     int32_t fd = -1;
 };
+
+}
+
 #endif // CONFIG_HAL_BOARD_SUBTYPE
diff --git a/libraries/AP_HAL_Linux/RCInput_UART.h b/libraries/AP_HAL_Linux/RCInput_UART.h
index 95a1bf0b8b..fbbfd015ca 100644
--- a/libraries/AP_HAL_Linux/RCInput_UART.h
+++ b/libraries/AP_HAL_Linux/RCInput_UART.h
@@ -7,7 +7,9 @@
 
 #define CHANNELS 8
 
-class Linux::RCInput_UART : public Linux::RCInput
+namespace Linux {
+
+class RCInput_UART : public RCInput
 {
 public:
     RCInput_UART(const char *path);
@@ -25,3 +27,5 @@ private:
         uint16_t values[CHANNELS];
     } _data;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_UDP.h b/libraries/AP_HAL_Linux/RCInput_UDP.h
index 3658f73d95..5343594925 100644
--- a/libraries/AP_HAL_Linux/RCInput_UDP.h
+++ b/libraries/AP_HAL_Linux/RCInput_UDP.h
@@ -6,7 +6,9 @@
 
 #define RCINPUT_UDP_DEF_PORT 777
 
-class Linux::RCInput_UDP : public Linux::RCInput
+namespace Linux {
+
+class RCInput_UDP : public RCInput
 {
 public:
     RCInput_UDP();
@@ -19,3 +21,5 @@ private:
     uint64_t _last_buf_ts;
     uint16_t _last_buf_seq;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCInput_ZYNQ.cpp b/libraries/AP_HAL_Linux/RCInput_ZYNQ.cpp
index 14ff12102d..be141e4649 100644
--- a/libraries/AP_HAL_Linux/RCInput_ZYNQ.cpp
+++ b/libraries/AP_HAL_Linux/RCInput_ZYNQ.cpp
@@ -1,3 +1,5 @@
+#include "RCInput_ZYNQ.h"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <poll.h>
@@ -13,7 +15,6 @@
 #include <AP_HAL/AP_HAL.h>
 
 #include "GPIO.h"
-#include "RCInput.h"
 
 extern const AP_HAL::HAL& hal;
 
diff --git a/libraries/AP_HAL_Linux/RCInput_ZYNQ.h b/libraries/AP_HAL_Linux/RCInput_ZYNQ.h
index ead6e779d0..30b66ab4be 100644
--- a/libraries/AP_HAL_Linux/RCInput_ZYNQ.h
+++ b/libraries/AP_HAL_Linux/RCInput_ZYNQ.h
@@ -5,18 +5,19 @@
   logic doing the edge detection of the PPM sum input
  */
 
-#include "AP_HAL_Linux.h"
+#include "RCInput.h"
 
 // FIXME A puppie dies when you hard code an address
 #define RCIN_ZYNQ_PULSE_INPUT_BASE  0x43c10000
 
-class Linux::RCInput_ZYNQ : public Linux::RCInput
-{
+namespace Linux {
+
+class RCInput_ZYNQ : public RCInput {
 public:
     void init();
     void _timer_tick(void);
 
- private:
+private:
     static const int TICK_PER_US=100;
     static const int TICK_PER_S=100000000;
 
@@ -26,3 +27,5 @@ public:
     // time spent in the low state
     uint32_t _s0_time;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_AioPRU.h b/libraries/AP_HAL_Linux/RCOutput_AioPRU.h
index 9e5ff56041..b041a76806 100644
--- a/libraries/AP_HAL_Linux/RCOutput_AioPRU.h
+++ b/libraries/AP_HAL_Linux/RCOutput_AioPRU.h
@@ -16,7 +16,9 @@
 #define RCOUT_PRUSS_IRAM_BASE 0x4a338000
 #define PWM_CHAN_COUNT 12
 
-class Linux::RCOutput_AioPRU : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_AioPRU : public AP_HAL::RCOutput {
     void     init();
     void     set_freq(uint32_t chmask, uint16_t freq_hz);
     uint16_t get_freq(uint8_t ch);
@@ -40,3 +42,5 @@ private:
 
     volatile struct pwm *pwm;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_Bebop.h b/libraries/AP_HAL_Linux/RCOutput_Bebop.h
index 348387db10..b213ced292 100644
--- a/libraries/AP_HAL_Linux/RCOutput_Bebop.h
+++ b/libraries/AP_HAL_Linux/RCOutput_Bebop.h
@@ -3,6 +3,10 @@
 #include "AP_HAL_Linux.h"
 #include <AP_HAL/I2CDevice.h>
 
+struct bldc_info;
+
+namespace Linux {
+
 enum bebop_bldc_motor {
     BEBOP_BLDC_MOTOR_1 = 0,
 #if CONFIG_HAL_BOARD_SUBTYPE != HAL_BOARD_SUBTYPE_LINUX_DISCO
@@ -49,9 +53,7 @@ public:
     uint8_t temperature;
 };
 
-struct bldc_info;
-
-class Linux::RCOutput_Bebop : public AP_HAL::RCOutput {
+class RCOutput_Bebop : public AP_HAL::RCOutput {
 public:
     RCOutput_Bebop(AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev);
 
@@ -102,3 +104,5 @@ private:
     void _run_rcout();
     static void *_control_thread(void *arg);
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_Disco.h b/libraries/AP_HAL_Linux/RCOutput_Disco.h
index 2be68d8a3b..f7b0977adc 100644
--- a/libraries/AP_HAL_Linux/RCOutput_Disco.h
+++ b/libraries/AP_HAL_Linux/RCOutput_Disco.h
@@ -4,7 +4,9 @@
 #include "RCOutput_Sysfs.h"
 #include "RCOutput_Bebop.h"
 
-class Linux::RCOutput_Disco : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_Disco : public AP_HAL::RCOutput {
 public:
     RCOutput_Disco(AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev);
     ~RCOutput_Disco() {}
@@ -51,5 +53,6 @@ private:
         { sysfs_out, 5 },
         { sysfs_out, 0 },
     };
-    
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_PCA9685.h b/libraries/AP_HAL_Linux/RCOutput_PCA9685.h
index 7199ada4fa..79d545138e 100644
--- a/libraries/AP_HAL_Linux/RCOutput_PCA9685.h
+++ b/libraries/AP_HAL_Linux/RCOutput_PCA9685.h
@@ -9,8 +9,10 @@
 #define PCA9685_TERTIARY_ADDRESS            0x42
 #define PCA9685_QUATENARY_ADDRESS           0x55
 
-class Linux::RCOutput_PCA9685 : public AP_HAL::RCOutput {
-    public:
+namespace Linux {
+
+class RCOutput_PCA9685 : public AP_HAL::RCOutput {
+public:
     RCOutput_PCA9685(AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev,
                      bool external_clock,
                      uint8_t channel_offset,
@@ -45,3 +47,5 @@ private:
     int16_t _oe_pin_number;
     uint16_t _pending_write_mask;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_PRU.h b/libraries/AP_HAL_Linux/RCOutput_PRU.h
index 83ebde4d3b..3115787db7 100644
--- a/libraries/AP_HAL_Linux/RCOutput_PRU.h
+++ b/libraries/AP_HAL_Linux/RCOutput_PRU.h
@@ -13,7 +13,9 @@
 #define PWM_CMD_CLR	         5	/* clr a pwm output explicitly */
 #define PWM_CMD_TEST	         6	/* various crap */
 
-class Linux::RCOutput_PRU : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_PRU : public AP_HAL::RCOutput {
     void     init();
     void     set_freq(uint32_t chmask, uint16_t freq_hz);
     uint16_t get_freq(uint8_t ch);
@@ -37,3 +39,5 @@ private:
     volatile struct pwm_cmd *sharedMem_cmd;
 
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_Raspilot.h b/libraries/AP_HAL_Linux/RCOutput_Raspilot.h
index eabf2a50a5..3eea9c95db 100644
--- a/libraries/AP_HAL_Linux/RCOutput_Raspilot.h
+++ b/libraries/AP_HAL_Linux/RCOutput_Raspilot.h
@@ -3,7 +3,10 @@
 #include "AP_HAL_Linux.h"
 #include <AP_HAL/SPIDevice.h>
 
-class Linux::RCOutput_Raspilot : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_Raspilot : public AP_HAL::RCOutput {
+public:
     void     init();
     void     set_freq(uint32_t chmask, uint16_t freq_hz);
     uint16_t get_freq(uint8_t ch);
@@ -16,10 +19,12 @@ class Linux::RCOutput_Raspilot : public AP_HAL::RCOutput {
 private:
     void reset();
     void _update(void);
-    
+
     AP_HAL::OwnPtr<AP_HAL::SPIDevice> _dev;
-    
+
     uint32_t _last_update_timestamp;
     uint16_t _frequency;
     uint16_t _period_us[8];
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_Sysfs.h b/libraries/AP_HAL_Linux/RCOutput_Sysfs.h
index 90fdd6e6c9..8591627434 100644
--- a/libraries/AP_HAL_Linux/RCOutput_Sysfs.h
+++ b/libraries/AP_HAL_Linux/RCOutput_Sysfs.h
@@ -3,7 +3,9 @@
 #include "AP_HAL_Linux.h"
 #include "PWM_Sysfs.h"
 
-class Linux::RCOutput_Sysfs : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_Sysfs : public AP_HAL::RCOutput {
 public:
     RCOutput_Sysfs(uint8_t chip, uint8_t channel_base, uint8_t channel_count);
     ~RCOutput_Sysfs();
@@ -28,3 +30,5 @@ private:
     const uint8_t _channel_count;
     PWM_Sysfs_Base **_pwm_channels;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_ZYNQ.h b/libraries/AP_HAL_Linux/RCOutput_ZYNQ.h
index 30a2bfdaf2..829e40af84 100644
--- a/libraries/AP_HAL_Linux/RCOutput_ZYNQ.h
+++ b/libraries/AP_HAL_Linux/RCOutput_ZYNQ.h
@@ -11,8 +11,13 @@
 #define PWM_CMD_CLR	         5	/* clr a pwm output explicitly */
 #define PWM_CMD_TEST	         6	/* various crap */
 
+#include <AP_HAL/AP_HAL.h>
 
-class Linux::RCOutput_ZYNQ : public AP_HAL::RCOutput {
+namespace Linux {
+
+
+class RCOutput_ZYNQ : public AP_HAL::RCOutput {
+public:
     void     init();
     void     set_freq(uint32_t chmask, uint16_t freq_hz);
     uint16_t get_freq(uint8_t ch);
@@ -36,3 +41,5 @@ private:
     };
     volatile struct pwm_cmd *sharedMem_cmd;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/RCOutput_qflight.h b/libraries/AP_HAL_Linux/RCOutput_qflight.h
index 89e832acf4..fe0e1253fd 100644
--- a/libraries/AP_HAL_Linux/RCOutput_qflight.h
+++ b/libraries/AP_HAL_Linux/RCOutput_qflight.h
@@ -5,7 +5,9 @@
 
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_QFLIGHT
 
-class Linux::RCOutput_QFLIGHT : public AP_HAL::RCOutput {
+namespace Linux {
+
+class RCOutput_QFLIGHT : public AP_HAL::RCOutput {
 public:
     void init();
     void set_freq(uint32_t chmask, uint16_t freq_hz);
@@ -19,18 +21,18 @@ public:
 
 private:
     const char *device = nullptr;
-    const uint32_t baudrate = 115200;    
+    const uint32_t baudrate = 115200;
     static const uint8_t channel_count = 4;
-    
+
     int32_t fd = -1;
     uint16_t enable_mask;
     uint16_t period[channel_count];
     volatile bool need_write;
-    
+
     void timer_update(void);
 
     void check_rc_in(void);
-    
+
     uint32_t last_read_check_ms;
     struct PACKED rcin_frame {
         uint8_t magic;
@@ -44,4 +46,6 @@ private:
     uint8_t nrcin_bytes;
 };
 
+}
+
 #endif // CONFIG_HAL_BOARD_SUBTYPE
diff --git a/libraries/AP_HAL_Linux/RPIOUARTDriver.h b/libraries/AP_HAL_Linux/RPIOUARTDriver.h
index 047063c600..45d2a73a91 100644
--- a/libraries/AP_HAL_Linux/RPIOUARTDriver.h
+++ b/libraries/AP_HAL_Linux/RPIOUARTDriver.h
@@ -5,8 +5,9 @@
 #include "UARTDriver.h"
 #include <AP_HAL/SPIDevice.h>
 
+namespace Linux {
 
-class Linux::RPIOUARTDriver : public Linux::UARTDriver {
+class RPIOUARTDriver : public UARTDriver {
 public:
     RPIOUARTDriver();
 
@@ -37,3 +38,5 @@ private:
     bool _need_set_baud;
     uint32_t _baudrate;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/SPIUARTDriver.h b/libraries/AP_HAL_Linux/SPIUARTDriver.h
index 56f04847c6..f845e2f5ca 100644
--- a/libraries/AP_HAL_Linux/SPIUARTDriver.h
+++ b/libraries/AP_HAL_Linux/SPIUARTDriver.h
@@ -4,8 +4,9 @@
 
 #include "UARTDriver.h"
 
+namespace Linux {
 
-class Linux::SPIUARTDriver : public Linux::UARTDriver {
+class SPIUARTDriver : public UARTDriver {
 public:
     SPIUARTDriver();
     void begin(uint32_t b, uint16_t rxS, uint16_t txS);
@@ -23,3 +24,5 @@ protected:
 
     bool _external;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Scheduler.h b/libraries/AP_HAL_Linux/Scheduler.h
index 106f74c8e7..1aaf10645e 100644
--- a/libraries/AP_HAL_Linux/Scheduler.h
+++ b/libraries/AP_HAL_Linux/Scheduler.h
@@ -10,7 +10,9 @@
 #define LINUX_SCHEDULER_MAX_TIMESLICED_PROCS 10
 #define LINUX_SCHEDULER_MAX_IO_PROCS 10
 
-class Linux::Scheduler : public AP_HAL::Scheduler {
+namespace Linux {
+
+class Scheduler : public AP_HAL::Scheduler {
 public:
     Scheduler();
 
@@ -109,3 +111,5 @@ private:
     Semaphore _timer_semaphore;
     Semaphore _io_semaphore;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Semaphores.h b/libraries/AP_HAL_Linux/Semaphores.h
index 7e8222a9fc..fdfc5e5e0f 100644
--- a/libraries/AP_HAL_Linux/Semaphores.h
+++ b/libraries/AP_HAL_Linux/Semaphores.h
@@ -6,7 +6,9 @@
 
 #include "AP_HAL_Linux.h"
 
-class Linux::Semaphore : public AP_HAL::Semaphore {
+namespace Linux {
+
+class Semaphore : public AP_HAL::Semaphore {
 public:
     Semaphore() {
         pthread_mutex_init(&_lock, NULL);
@@ -17,3 +19,5 @@ public:
 private:
     pthread_mutex_t _lock;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Storage.h b/libraries/AP_HAL_Linux/Storage.h
index b56ac5a28e..333fc43b34 100644
--- a/libraries/AP_HAL_Linux/Storage.h
+++ b/libraries/AP_HAL_Linux/Storage.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <AP_HAL/AP_HAL.h>
-#include "AP_HAL_Linux_Namespace.h"
 
 #define LINUX_STORAGE_SIZE HAL_STORAGE_SIZE
 #define LINUX_STORAGE_MAX_WRITE 512
@@ -9,7 +8,9 @@
 #define LINUX_STORAGE_LINE_SIZE (1<<LINUX_STORAGE_LINE_SHIFT)
 #define LINUX_STORAGE_NUM_LINES (LINUX_STORAGE_SIZE/LINUX_STORAGE_LINE_SIZE)
 
-class Linux::Storage : public AP_HAL::Storage
+namespace Linux {
+
+class Storage : public AP_HAL::Storage
 {
 public:
     Storage() : _fd(-1),_dirty_mask(0) { }
@@ -39,3 +40,5 @@ protected:
     uint8_t _buffer[LINUX_STORAGE_SIZE];
     volatile uint32_t _dirty_mask;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Thread.h b/libraries/AP_HAL_Linux/Thread.h
index 4d2bc1e447..5caa5f2863 100644
--- a/libraries/AP_HAL_Linux/Thread.h
+++ b/libraries/AP_HAL_Linux/Thread.h
@@ -23,8 +23,6 @@
 
 #include <AP_HAL/utility/functor.h>
 
-#include "AP_HAL_Linux_Namespace.h"
-
 namespace Linux {
 
 /*
diff --git a/libraries/AP_HAL_Linux/ToneAlarm.h b/libraries/AP_HAL_Linux/ToneAlarm.h
index 138094231f..6471fcc886 100644
--- a/libraries/AP_HAL_Linux/ToneAlarm.h
+++ b/libraries/AP_HAL_Linux/ToneAlarm.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include <AP_HAL/AP_HAL.h>
-#include "AP_HAL_Linux_Namespace.h"
 
 #define OCTAVE_OFFSET 0
 
@@ -109,7 +108,9 @@
 
 #define TONE_NUMBER_OF_TUNES 11
 
-class Linux::ToneAlarm{
+namespace Linux {
+
+class ToneAlarm {
 public:
 	ToneAlarm();
 	void set_tune(uint8_t tone);
@@ -141,3 +142,5 @@ private:
 	int32_t duty_fd;
 	int32_t run_fd;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/ToneAlarm_Raspilot.h b/libraries/AP_HAL_Linux/ToneAlarm_Raspilot.h
index 86a3002c49..33be2581a8 100644
--- a/libraries/AP_HAL_Linux/ToneAlarm_Raspilot.h
+++ b/libraries/AP_HAL_Linux/ToneAlarm_Raspilot.h
@@ -4,7 +4,9 @@
 
 #include "ToneAlarm.h"
 
-class Linux::ToneAlarm_Raspilot : public Linux::ToneAlarm {
+namespace Linux {
+
+class ToneAlarm_Raspilot : public ToneAlarm {
 public:
     ToneAlarm_Raspilot();
     bool init() override;
@@ -18,3 +20,5 @@ private:
     volatile uint32_t *_pwm;
     volatile uint32_t *_clk;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/UARTDriver.h b/libraries/AP_HAL_Linux/UARTDriver.h
index ec2d18aa93..4f42f88538 100644
--- a/libraries/AP_HAL_Linux/UARTDriver.h
+++ b/libraries/AP_HAL_Linux/UARTDriver.h
@@ -5,7 +5,9 @@
 #include "AP_HAL_Linux.h"
 #include "SerialDevice.h"
 
-class Linux::UARTDriver : public AP_HAL::UARTDriver {
+namespace Linux {
+
+class UARTDriver : public AP_HAL::UARTDriver {
 public:
     UARTDriver(bool default_console);
 
@@ -54,14 +56,14 @@ private:
     uint16_t _base_port;
     char *_ip;
     char *_flag;
-    bool _connected; // true if a client has connected         
+    bool _connected; // true if a client has connected
     bool _packetise; // true if writes should try to be on mavlink boundaries
 
     void _allocate_buffers(uint16_t rxS, uint16_t txS);
     void _deallocate_buffers();
 
     AP_HAL::OwnPtr<SerialDevice> _parseDevicePath(const char *arg);
-    uint64_t _last_write_time;    
+    uint64_t _last_write_time;
 
 protected:
     const char *device_path;
@@ -85,3 +87,5 @@ protected:
     virtual int _read_fd(uint8_t *buf, uint16_t n);
 
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Util.h b/libraries/AP_HAL_Linux/Util.h
index 47bdb65c10..8794d45935 100644
--- a/libraries/AP_HAL_Linux/Util.h
+++ b/libraries/AP_HAL_Linux/Util.h
@@ -3,11 +3,13 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_HAL/AP_HAL.h>
 
-#include "AP_HAL_Linux_Namespace.h"
+#include "Heat.h"
 #include "Perf.h"
 #include "ToneAlarm.h"
 #include "Semaphores.h"
 
+namespace Linux {
+
 enum hw_type {
     UTIL_HARDWARE_RPI1 = 0,
     UTIL_HARDWARE_RPI2,
@@ -17,7 +19,7 @@ enum hw_type {
     UTIL_NUM_HARDWARES,
 };
 
-class Linux::Util : public AP_HAL::Util {
+class Util : public AP_HAL::Util {
 public:
     static Util *from(AP_HAL::Util *util) {
         return static_cast<Util*>(util);
@@ -39,7 +41,7 @@ public:
     /*
       set system clock in UTC microseconds
      */
-    void set_system_clock(uint64_t time_utc_usec);    
+    void set_system_clock(uint64_t time_utc_usec);
     const char* get_custom_log_directory() { return custom_log_directory; }
     const char* get_custom_terrain_directory() { return custom_terrain_directory; }
 
@@ -87,20 +89,22 @@ public:
     }
 
     // create a new semaphore
-    AP_HAL::Semaphore *new_semaphore(void) override { return new Linux::Semaphore; }
+    AP_HAL::Semaphore *new_semaphore(void) override { return new Semaphore; }
 
     int get_hw_arm32();
 
 private:
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_RASPILOT
-    static Linux::ToneAlarm_Raspilot _toneAlarm;
+    static ToneAlarm_Raspilot _toneAlarm;
 #else
-    static Linux::ToneAlarm _toneAlarm;
+    static ToneAlarm _toneAlarm;
 #endif
-    Linux::Heat *_heat;
+    Heat *_heat;
     int saved_argc;
     char* const *saved_argv;
     const char* custom_log_directory = NULL;
     const char* custom_terrain_directory = NULL;
     static const char *_hw_names[UTIL_NUM_HARDWARES];
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/Util_RPI.h b/libraries/AP_HAL_Linux/Util_RPI.h
index 8dc7a3ef75..fdd0aca365 100644
--- a/libraries/AP_HAL_Linux/Util_RPI.h
+++ b/libraries/AP_HAL_Linux/Util_RPI.h
@@ -2,7 +2,9 @@
 
 #include "Util.h"
 
-class Linux::UtilRPI : public Linux::Util {
+namespace Linux {
+
+class UtilRPI : public Util {
 public:
     UtilRPI();
 
@@ -20,3 +22,5 @@ protected:
 private:
     int _rpi_version = 0;
 };
+
+}
diff --git a/libraries/AP_HAL_Linux/VideoIn.h b/libraries/AP_HAL_Linux/VideoIn.h
index 436197786d..ed4fd90180 100644
--- a/libraries/AP_HAL_Linux/VideoIn.h
+++ b/libraries/AP_HAL_Linux/VideoIn.h
@@ -18,12 +18,14 @@
 #include <linux/videodev2.h>
 #include <vector>
 
+namespace Linux {
+
 struct buffer {
     unsigned int size;
     void *mem;
 };
 
-class Linux::VideoIn {
+class VideoIn {
 public:
     /* This structure implements the fields of the v4l2_pix_format struct
      * that are considered useful for an optical flow application along
@@ -80,3 +82,5 @@ private:
     uint32_t _sizeimage;
     uint32_t _memtype = V4L2_MEMORY_MMAP;
 };
+
+}