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_ */
58