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author | Arend van Spriel <arend@broadcom.com> | 2011-05-31 11:22:16 +0200 |
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committer | John W. Linville <linville@tuxdriver.com> | 2011-06-03 15:01:07 -0400 |
commit | 10f8113ecb76eea72f96c7cfb72d7fed7c282565 (patch) | |
tree | 85dd734aeee52e3f21851f11436f4dabaf130033 /include/linux/cordic.h | |
parent | 7150962d637cf38617924f7f72ea00612283eb89 (diff) | |
download | linux-stable-10f8113ecb76eea72f96c7cfb72d7fed7c282565.tar.gz linux-stable-10f8113ecb76eea72f96c7cfb72d7fed7c282565.tar.bz2 linux-stable-10f8113ecb76eea72f96c7cfb72d7fed7c282565.zip |
lib: cordic: add library module providing cordic angle calculation
The brcm80211 driver in the staging tree has a cordic function to
determine cosine and sine for a given angle. Feedback received from
John Linville suggested that these kind of functions should be made
available to others as a library function in the kernel tree. The
b43 driver also has a cordic angle calculation implemented.
Cc: linux-kernel@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Henry Ptasinski <henryp@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'include/linux/cordic.h')
-rw-r--r-- | include/linux/cordic.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/include/linux/cordic.h b/include/linux/cordic.h new file mode 100644 index 000000000000..f932093e20c2 --- /dev/null +++ b/include/linux/cordic.h @@ -0,0 +1,48 @@ +/* + * Copyright (c) 2011 Broadcom Corporation + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY + * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION + * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ +#ifndef __CORDIC_H_ +#define __CORDIC_H_ + +#include <linux/types.h> + +/** + * struct cordic_iq - i/q coordinate. + * + * @i: real part of coordinate (in phase). + * @q: imaginary part of coordinate (quadrature). + */ +struct cordic_iq { + s32 i; + s32 q; +}; + +/** + * cordic_calc_iq() - calculates the i/q coordinate for given angle. + * + * @theta: angle in degrees for which i/q coordinate is to be calculated. + * @coord: function output parameter holding the i/q coordinate. + * + * The function calculates the i/q coordinate for a given angle using + * cordic algorithm. The coordinate consists of a real (i) and an + * imaginary (q) part. The real part is essentially the cosine of the + * angle and the imaginary part is the sine of the angle. The returned + * values are scaled by 2^16 for precision. The range for theta is + * for -180 degrees to +180 degrees. Passed values outside this range are + * converted before doing the actual calculation. + */ +struct cordic_iq cordic_calc_iq(s32 theta); + +#endif /* __CORDIC_H_ */ |