Comments and documentation fixes.

cpu/arm/stm32l152/clock.c

@@ -92,9 +92,7 @@ void clock_delay(unsigned int i)
   }
 }
 /*---------------------------------------------------------------------------*/
-/**
- * Wait for a multiple of clock ticks (7.8 ms at 128 Hz).
- */
+/* Wait for a multiple of clock ticks (7.8 ms at 128 Hz). */
 void clock_wait(clock_time_t t)
 {
   clock_time_t start;

examples/stm32nucleo-spirit1/sensor-demo/sensor-demo.c

@@ -131,6 +131,11 @@ PROCESS_THREAD(sensor_demo_process, ev, data)
     sensor_value = pressure_sensor.value(0);
     printf("Pressure:\t%d.%d mbar\n", sensor_value/10, ABS_VALUE(sensor_value)%10);
 
+  /* NOTE: this demo uses the mapping of ST Nucleo sensors on Contiki sensor API.
+   * For a real use case of sensors like acceleration, magneto and gyroscope,
+   * it is better to directly call the ST lib to get the three value (X/Y/Z)
+   * at once.
+   */
     printf("Magneto:\t%d/%d/%d (X/Y/Z) mgauss\n", magneto_sensor.value(X_AXIS),
                                                   magneto_sensor.value(Y_AXIS),
                                                   magneto_sensor.value(Z_AXIS));

platform/stm32nucleo-spirit1/README.md

@@ -63,15 +63,16 @@ Software Requirements
 The following software are needed:
 
 * ST port of Contiki for STM32 Nucleo and expansion boards. 
- >The port is installed automatically when both the Contiki and the submodule repository are cloned: the former hosts the Contiki distribution and the ST platform interface, the latter hosts the actual library.
+ >The port is automatically installed when both the Contiki and the submodule repository are cloned: the former hosts the Contiki distribution and the ST platform interface, the latter hosts the actual library.
 The following commands are needed to download the full porting:
 
-    git clone https://github.com/STclab/contiki.git (*)
+    git clone https://github.com/STclab/contiki.git
     cd contiki/
-    git checkout stm32nucleo-spirit1 (*)
+    git checkout stm32nucleo-spirit1
     git submodule init
     git submodule update
-(*): required only if using the STclab GitHub repository, these steps won't be needed once the Pull Request will be accepted
+
+Note: the first and third steps are required only if using the STclab GitHub repository, they won't be needed any more once the Pull Request is accepted.
 
 The platform name is: stm32nucleo-spirit1
 

platform/stm32nucleo-spirit1/dev/acceleration-sensor.c

@@ -80,6 +80,11 @@ static int value(int type)
   int32_t ret_val = 0;
   volatile st_lib_axes_raw_typedef axes_raw_data;
 
+  /* NOTE: this is a demo of mapping ST Nucleo sensors on Contiki sensor API.
+   * For a real use case of sensors like acceleration, magneto and gyroscope,
+   * it is better to directly call the ST lib to get the three value (X/Y/Z)
+   * at once.
+   */
   st_lib_bsp_imu_6axes_x_get_axes_raw(&axes_raw_data);
 
   switch (type) {

platform/stm32nucleo-spirit1/dev/gyroscope-sensor.c

@@ -80,6 +80,11 @@ static int value(int type)
   int32_t ret_val = 0;
   volatile st_lib_axes_raw_typedef axes_raw_data;
 
+  /* NOTE: this is a demo of mapping ST Nucleo sensors on Contiki sensor API.
+   * For a real use case of sensors like acceleration, magneto and gyroscope,
+   * it is better to directly call the ST lib to get the three value (X/Y/Z)
+   * at once.
+   */
   st_lib_bsp_imu_6axes_g_get_axes_raw(&axes_raw_data);
 
   switch (type) {

platform/stm32nucleo-spirit1/dev/magneto-sensor.c

@@ -76,6 +76,11 @@ static int value(int type)
   int32_t ret_val = 0;
   volatile st_lib_axes_raw_typedef axes_raw_data;
 
+  /* NOTE: this is a demo of mapping ST Nucleo sensors on Contiki sensor API.
+   * For a real use case of sensors like acceleration, magneto and gyroscope,
+   * it is better to directly call the ST lib to get the three value (X/Y/Z)
+   * at once.
+   */
   st_lib_bsp_magneto_m_get_axes_raw(&axes_raw_data);
 
   switch (type) {