include/linux/cordic.h

   1 /*
   2  * Copyright (c) 2011 Broadcom Corporation
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  11  * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  13  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  14  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 #ifndef __CORDIC_H_
  17 #define __CORDIC_H_
  18
  19 #include <linux/types.h>
  20
  21 /**
  22  * struct cordic_iq - i/q coordinate.
  23  *
  24  * @i: real part of coordinate (in phase).
  25  * @q: imaginary part of coordinate (quadrature).
  26  */
  27 struct cordic_iq {
  28         s32 i;
  29         s32 q;
  30 };
  31
  32 /**
  33  * cordic_calc_iq() - calculates the i/q coordinate for given angle.
  34  *
  35  * @theta: angle in degrees for which i/q coordinate is to be calculated.
  36  * @coord: function output parameter holding the i/q coordinate.
  37  *
  38  * The function calculates the i/q coordinate for a given angle using the
  39  * CORDIC algorithm. The coordinate consists of a real (i) and an
  40  * imaginary (q) part. The real part is essentially the cosine of the
  41  * angle and the imaginary part is the sine of the angle. The returned
  42  * values are scaled by 2^16 for precision. The range for theta is
  43  * for -180 degrees to +180 degrees. Passed values outside this range are
  44  * converted before doing the actual calculation.
  45  */
  46 struct cordic_iq cordic_calc_iq(s32 theta);
  47
  48 #endif /* __CORDIC_H_ */