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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/* Copyright(c) 2024 Realtek Corporation
*/
#include "util.h"
#define FRAC_ROWS 3
#define FRAC_ROW_MAX (FRAC_ROWS - 1)
#define NORM_ROW_MIN FRAC_ROWS
static const u32 db_invert_table[12][8] = {
/* rows 0~2 in unit of U(32,3) */
{10, 13, 16, 20, 25, 32, 40, 50},
{64, 80, 101, 128, 160, 201, 256, 318},
{401, 505, 635, 800, 1007, 1268, 1596, 2010},
/* rows 3~11 in unit of U(32,0) */
{316, 398, 501, 631, 794, 1000, 1259, 1585},
{1995, 2512, 3162, 3981, 5012, 6310, 7943, 10000},
{12589, 15849, 19953, 25119, 31623, 39811, 50119, 63098},
{79433, 100000, 125893, 158489, 199526, 251189, 316228, 398107},
{501187, 630957, 794328, 1000000, 1258925, 1584893, 1995262, 2511886},
{3162278, 3981072, 5011872, 6309573, 7943282, 1000000, 12589254,
15848932},
{19952623, 25118864, 31622777, 39810717, 50118723, 63095734, 79432823,
100000000},
{125892541, 158489319, 199526232, 251188643, 316227766, 398107171,
501187234, 630957345},
{794328235, 1000000000, 1258925412, 1584893192, 1995262315, 2511886432U,
3162277660U, 3981071706U},
};
u32 rtw89_linear_2_db(u64 val)
{
u8 i, j;
u32 dB;
for (i = 0; i < 12; i++) {
for (j = 0; j < 8; j++) {
if (i <= FRAC_ROW_MAX &&
(val << RTW89_LINEAR_FRAC_BITS) <= db_invert_table[i][j])
goto cnt;
else if (i > FRAC_ROW_MAX && val <= db_invert_table[i][j])
goto cnt;
}
}
return 96; /* maximum 96 dB */
cnt:
/* special cases */
if (j == 0 && i == 0)
goto end;
if (i == NORM_ROW_MIN && j == 0) {
if (db_invert_table[NORM_ROW_MIN][0] - val >
val - (db_invert_table[FRAC_ROW_MAX][7] >> RTW89_LINEAR_FRAC_BITS)) {
i = FRAC_ROW_MAX;
j = 7;
}
goto end;
}
if (i <= FRAC_ROW_MAX)
val <<= RTW89_LINEAR_FRAC_BITS;
/* compare difference to get precise dB */
if (j == 0) {
if (db_invert_table[i][j] - val >
val - db_invert_table[i - 1][7]) {
i--;
j = 7;
}
} else {
if (db_invert_table[i][j] - val >
val - db_invert_table[i][j - 1]) {
j--;
}
}
end:
dB = (i << 3) + j + 1;
return dB;
}
EXPORT_SYMBOL(rtw89_linear_2_db);
u64 rtw89_db_2_linear(u32 db)
{
u64 linear;
u8 i, j;
if (db > 96)
db = 96;
else if (db < 1)
return 1;
i = (db - 1) >> 3;
j = (db - 1) & 0x7;
linear = db_invert_table[i][j];
if (i >= NORM_ROW_MIN)
linear = linear << RTW89_LINEAR_FRAC_BITS;
return linear;
}
EXPORT_SYMBOL(rtw89_db_2_linear);
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