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path: root/drivers/net/wireless/b43/phy_common.c
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Diffstat (limited to 'drivers/net/wireless/b43/phy_common.c')
-rw-r--r--drivers/net/wireless/b43/phy_common.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/net/wireless/b43/phy_common.c b/drivers/net/wireless/b43/phy_common.c
index 75b26e175e8f..8f7d7eff2d80 100644
--- a/drivers/net/wireless/b43/phy_common.c
+++ b/drivers/net/wireless/b43/phy_common.c
@@ -421,3 +421,48 @@ void b43_phyop_switch_analog_generic(struct b43_wldev *dev, bool on)
{
b43_write16(dev, B43_MMIO_PHY0, on ? 0 : 0xF4);
}
+
+/* http://bcm-v4.sipsolutions.net/802.11/PHY/Cordic */
+struct b43_c32 b43_cordic(int theta)
+{
+ u32 arctg[] = { 2949120, 1740967, 919879, 466945, 234379, 117304,
+ 58666, 29335, 14668, 7334, 3667, 1833, 917, 458,
+ 229, 115, 57, 29, };
+ u8 i;
+ s32 tmp;
+ s8 signx = 1;
+ u32 angle = 0;
+ struct b43_c32 ret = { .i = 39797, .q = 0, };
+
+ while (theta > (180 << 16))
+ theta -= (360 << 16);
+ while (theta < -(180 << 16))
+ theta += (360 << 16);
+
+ if (theta > (90 << 16)) {
+ theta -= (180 << 16);
+ signx = -1;
+ } else if (theta < -(90 << 16)) {
+ theta += (180 << 16);
+ signx = -1;
+ }
+
+ for (i = 0; i <= 17; i++) {
+ if (theta > angle) {
+ tmp = ret.i - (ret.q >> i);
+ ret.q += ret.i >> i;
+ ret.i = tmp;
+ angle += arctg[i];
+ } else {
+ tmp = ret.i + (ret.q >> i);
+ ret.q -= ret.i >> i;
+ ret.i = tmp;
+ angle -= arctg[i];
+ }
+ }
+
+ ret.i *= signx;
+ ret.q *= signx;
+
+ return ret;
+}