libdsp: add one_by_p to motor_phy_params

include/dsp.h

@@ -386,6 +386,7 @@ struct motor_phy_params_f32_s
   float   res;                 /* Phase-to-neutral resistance */
   float   ind;                 /* Average phase-to-neutral inductance */
   float   one_by_ind;          /* Inverse phase-to-neutral inductance */
+  float   one_by_p;            /* Inverse number of motor pole pairs */
 };
 
 /* PMSM motor physcial parameters */

include/dspb16.h

@@ -299,6 +299,7 @@ struct motor_phy_params_b16_s
                                 */
   b16_t   ind;                 /* Average phase-to-neutral inductance */
   b16_t   one_by_ind;          /* Inverse phase-to-neutral inductance */
+  b16_t   one_by_p;            /* Inverse number of motor pole pairs */
 };
 
 /* PMSM motor physcial parameters */

libs/libdsp/lib_motor.c

@@ -372,6 +372,7 @@ void motor_phy_params_init(FAR struct motor_phy_params_f32_s *phy,
   phy->res        = res;
   phy->ind        = ind;
   phy->one_by_ind = (1.0f / ind);
+  phy->one_by_p   = (1.0f / poles);
 }
 
 /****************************************************************************

libs/libdsp/lib_motor_b16.c

@@ -324,6 +324,7 @@ void motor_phy_params_init_b16(FAR struct motor_phy_params_b16_s *phy,
   phy->res        = res;
   phy->ind        = ind;
   phy->one_by_ind = b16divb16(b16ONE, ind);
+  phy->one_by_p   = b16divb16(b16ONE, poles);
 }
 
 /****************************************************************************