HAL_Linux: implement set_split_transfers() API for I2C

libraries/AP_HAL_Linux/I2CDevice.cpp

@@ -154,6 +154,16 @@ I2CDevice::~I2CDevice()
 bool I2CDevice::transfer(const uint8_t *send, uint32_t send_len,
                          uint8_t *recv, uint32_t recv_len)
 {
+    if (send_len > 0 && recv_len > 0 && _split_transfers) {
+        /*
+          optionally split all I2C transfers. This is needed for some
+          devices (such as LidarLite) that require that STOP only
+          happen with SCL high
+         */
+        return transfer(send, send_len, nullptr, 0) &&
+            transfer(nullptr, 0, recv, recv_len);
+    }
+    
     struct i2c_msg msgs[2] = { };
     unsigned nmsgs = 0;
 

libraries/AP_HAL_Linux/I2CDevice.h

@@ -71,10 +71,16 @@ public:
     bool adjust_periodic_callback(
         AP_HAL::Device::PeriodicHandle h, uint32_t period_usec) override;
 
+    /* set split transfers flag */
+    void set_split_transfers(bool set) override {
+        _split_transfers = set;
+    }
+    
 protected:
     I2CBus &_bus;
     uint8_t _address;
     uint8_t _retries = 0;
+    bool _split_transfers = false;
 };
 
 class I2CDeviceManager : public AP_HAL::I2CDeviceManager {