1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* Copyright(c) 2024 Realtek Corporation 3 */ 4 5 #include "util.h" 6 7 #define FRAC_ROWS 3 8 #define FRAC_ROW_MAX (FRAC_ROWS - 1) 9 #define NORM_ROW_MIN FRAC_ROWS 10 11 static const u32 db_invert_table[12][8] = { 12 /* rows 0~2 in unit of U(32,3) */ 13 {10, 13, 16, 20, 25, 32, 40, 50}, 14 {64, 80, 101, 128, 160, 201, 256, 318}, 15 {401, 505, 635, 800, 1007, 1268, 1596, 2010}, 16 /* rows 3~11 in unit of U(32,0) */ 17 {316, 398, 501, 631, 794, 1000, 1259, 1585}, 18 {1995, 2512, 3162, 3981, 5012, 6310, 7943, 10000}, 19 {12589, 15849, 19953, 25119, 31623, 39811, 50119, 63098}, 20 {79433, 100000, 125893, 158489, 199526, 251189, 316228, 398107}, 21 {501187, 630957, 794328, 1000000, 1258925, 1584893, 1995262, 2511886}, 22 {3162278, 3981072, 5011872, 6309573, 7943282, 1000000, 12589254, 23 15848932}, 24 {19952623, 25118864, 31622777, 39810717, 50118723, 63095734, 79432823, 25 100000000}, 26 {125892541, 158489319, 199526232, 251188643, 316227766, 398107171, 27 501187234, 630957345}, 28 {794328235, 1000000000, 1258925412, 1584893192, 1995262315, 2511886432U, 29 3162277660U, 3981071706U}, 30 }; 31 32 u32 rtw89_linear_2_db(u64 val) 33 { 34 u8 i, j; 35 u32 dB; 36 37 for (i = 0; i < 12; i++) { 38 for (j = 0; j < 8; j++) { 39 if (i <= FRAC_ROW_MAX && 40 (val << RTW89_LINEAR_FRAC_BITS) <= db_invert_table[i][j]) 41 goto cnt; 42 else if (i > FRAC_ROW_MAX && val <= db_invert_table[i][j]) 43 goto cnt; 44 } 45 } 46 47 return 96; /* maximum 96 dB */ 48 49 cnt: 50 /* special cases */ 51 if (j == 0 && i == 0) 52 goto end; 53 54 if (i == NORM_ROW_MIN && j == 0) { 55 if (db_invert_table[NORM_ROW_MIN][0] - val > 56 val - (db_invert_table[FRAC_ROW_MAX][7] >> RTW89_LINEAR_FRAC_BITS)) { 57 i = FRAC_ROW_MAX; 58 j = 7; 59 } 60 goto end; 61 } 62 63 if (i <= FRAC_ROW_MAX) 64 val <<= RTW89_LINEAR_FRAC_BITS; 65 66 /* compare difference to get precise dB */ 67 if (j == 0) { 68 if (db_invert_table[i][j] - val > 69 val - db_invert_table[i - 1][7]) { 70 i--; 71 j = 7; 72 } 73 } else { 74 if (db_invert_table[i][j] - val > 75 val - db_invert_table[i][j - 1]) { 76 j--; 77 } 78 } 79 end: 80 dB = (i << 3) + j + 1; 81 82 return dB; 83 } 84 EXPORT_SYMBOL(rtw89_linear_2_db); 85 86 u64 rtw89_db_2_linear(u32 db) 87 { 88 u64 linear; 89 u8 i, j; 90 91 if (db > 96) 92 db = 96; 93 else if (db < 1) 94 return 1; 95 96 i = (db - 1) >> 3; 97 j = (db - 1) & 0x7; 98 99 linear = db_invert_table[i][j]; 100 101 if (i >= NORM_ROW_MIN) 102 linear = linear << RTW89_LINEAR_FRAC_BITS; 103 104 return linear; 105 } 106 EXPORT_SYMBOL(rtw89_db_2_linear); 107