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 #define CORDIC_ANGLE_GEN 39797
22 #define CORDIC_PRECISION_SHIFT 16
23 #define CORDIC_NUM_ITER (CORDIC_PRECISION_SHIFT + 2)
24
25 #define CORDIC_FIXED(X) ((s32)((X) << CORDIC_PRECISION_SHIFT))
26 #define CORDIC_FLOAT(X) (((X) >= 0) \
27 ? ((((X) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1) \
28 : -((((-(X)) >> (CORDIC_PRECISION_SHIFT - 1)) + 1) >> 1))
29
30 /**
31 * struct cordic_iq - i/q coordinate.
32 *
33 * @i: real part of coordinate (in phase).
34 * @q: imaginary part of coordinate (quadrature).
35 */
36 struct cordic_iq {
37 s32 i;
38 s32 q;
39 };
40
41 /**
42 * cordic_calc_iq() - calculates the i/q coordinate for given angle.
43 *
44 * @theta: angle in degrees for which i/q coordinate is to be calculated.
45 * @coord: function output parameter holding the i/q coordinate.
46 *
47 * The function calculates the i/q coordinate for a given angle using the
48 * CORDIC algorithm. The coordinate consists of a real (i) and an
49 * imaginary (q) part. The real part is essentially the cosine of the
50 * angle and the imaginary part is the sine of the angle. The returned
51 * values are scaled by 2^16 for precision. The range for theta is
52 * for -180 degrees to +180 degrees. Passed values outside this range are
53 * converted before doing the actual calculation.
54 */
55 struct cordic_iq cordic_calc_iq(s32 theta);
56
57 #endif /* __CORDIC_H_ */