Typo fixes.

include/dsp.h

@@ -389,7 +389,7 @@ struct motor_phy_params_f32_s
   float   one_by_p;            /* Inverse number of motor pole pairs */
 };
 
-/* PMSM motor physcial parameters */
+/* PMSM motor physical parameters */
 
 struct pmsm_phy_params_f32_s
 {
@@ -397,7 +397,7 @@ struct pmsm_phy_params_f32_s
   float                         iner;        /* Rotor inertia */
   float                         ind_d;       /* d-inductance */
   float                         ind_q;       /* q-inductance */
-  float                         one_by_iner; /* One by intertia */
+  float                         one_by_iner; /* One by inertia */
   float                         one_by_indd; /* One by Ld */
   float                         one_by_indq; /* One by Lq */
 };

include/nuttx/arch.h

@@ -1513,7 +1513,7 @@ void up_timer_initialize(void);
  *
  * Description:
  *   Return the elapsed time since power-up (or, more correctly, since
- *   the archtecture-specific timer was initialized).  This function is
+ *   the architecture-specific timer was initialized).  This function is
  *   functionally equivalent to:
  *
  *      int clock_gettime(clockid_t clockid, FAR struct timespec *ts);
@@ -2103,7 +2103,7 @@ char up_romgetc(FAR const char *ptr);
  * Name: up_mdelay and up_udelay
  *
  * Description:
- *   Some device drivers may require that the plaform-specific logic
+ *   Some device drivers may require that the platform-specific logic
  *   provides these timing loops for short delays.
  *
  ****************************************************************************/
@@ -2211,7 +2211,7 @@ void nxsched_process_cpuload_ticks(uint32_t ticks);
  * Name: irq_dispatch
  *
  * Description:
- *   This function must be called from the achitecture-specific logic in
+ *   This function must be called from the architecture-specific logic in
  *   order to dispatch an interrupt to the appropriate, registered handling
  *   logic.
  *

include/nuttx/usb/audio.h

@@ -550,7 +550,7 @@
 /* Input Terminal Types */
 
 #define ADC_INTERM_UNDEF            0x0200     /* Undefined Type */
-#define ADC_INTERM_MIC              0x0201     /* A generic microhpone */
+#define ADC_INTERM_MIC              0x0201     /* A generic microphone */
 #define ADC_INTERM_DESKTOP_MIC      0x0202     /* A desktop microphone */
 #define ADC_INTERM_PERSONAL_MIC     0x0203     /* Head-mounted or clip-on microphone */
 #define ADC_INTERM_OMNI_MIC         0x0204     /* Omni-directional microphone */