linux/drivers/thermal/tegra/soctherm-fuse.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2014-2016, NVIDIA CORPORATION.  All rights reserved.
   4 */
   5
   6#include <linux/module.h>
   7#include <linux/platform_device.h>
   8#include <soc/tegra/fuse.h>
   9
  10#include "soctherm.h"
  11
  12#define NOMINAL_CALIB_FT                        105
  13#define NOMINAL_CALIB_CP                        25
  14
  15#define FUSE_TSENSOR_CALIB_CP_TS_BASE_MASK      0x1fff
  16#define FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK      (0x1fff << 13)
  17#define FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT     13
  18
  19#define FUSE_TSENSOR_COMMON                     0x180
  20
  21/*
  22 * Tegra210: Layout of bits in FUSE_TSENSOR_COMMON:
  23 *    3                   2                   1                   0
  24 *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  25 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  26 * |       BASE_FT       |      BASE_CP      | SHFT_FT | SHIFT_CP  |
  27 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  28 *
  29 * Tegra12x, etc:
  30 * In chips prior to Tegra210, this fuse was incorrectly sized as 26 bits,
  31 * and didn't hold SHIFT_CP in [31:26]. Therefore these missing six bits
  32 * were obtained via the FUSE_SPARE_REALIGNMENT_REG register [5:0].
  33 *
  34 * FUSE_TSENSOR_COMMON:
  35 *    3                   2                   1                   0
  36 *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  37 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  38 * |-----------| SHFT_FT |       BASE_FT       |      BASE_CP      |
  39 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  40 *
  41 * FUSE_SPARE_REALIGNMENT_REG:
  42 *    3                   2                   1                   0
  43 *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  44 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45 * |---------------------------------------------------| SHIFT_CP  |
  46 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47 */
  48
  49#define CALIB_COEFFICIENT 1000000LL
  50
  51/**
  52 * div64_s64_precise() - wrapper for div64_s64()
  53 * @a:  the dividend
  54 * @b:  the divisor
  55 *
  56 * Implements division with fairly accurate rounding instead of truncation by
  57 * shifting the dividend to the left by 16 so that the quotient has a
  58 * much higher precision.
  59 *
  60 * Return: the quotient of a / b.
  61 */
  62static s64 div64_s64_precise(s64 a, s32 b)
  63{
  64        s64 r, al;
  65
  66        /* Scale up for increased precision division */
  67        al = a << 16;
  68
  69        r = div64_s64(al * 2 + 1, 2 * b);
  70        return r >> 16;
  71}
  72
  73int tegra_calc_shared_calib(const struct tegra_soctherm_fuse *tfuse,
  74                            struct tsensor_shared_calib *shared)
  75{
  76        u32 val;
  77        s32 shifted_cp, shifted_ft;
  78        int err;
  79
  80        err = tegra_fuse_readl(FUSE_TSENSOR_COMMON, &val);
  81        if (err)
  82                return err;
  83
  84        shared->base_cp = (val & tfuse->fuse_base_cp_mask) >>
  85                          tfuse->fuse_base_cp_shift;
  86        shared->base_ft = (val & tfuse->fuse_base_ft_mask) >>
  87                          tfuse->fuse_base_ft_shift;
  88
  89        shifted_ft = (val & tfuse->fuse_shift_ft_mask) >>
  90                     tfuse->fuse_shift_ft_shift;
  91        shifted_ft = sign_extend32(shifted_ft, 4);
  92
  93        if (tfuse->fuse_spare_realignment) {
  94                err = tegra_fuse_readl(tfuse->fuse_spare_realignment, &val);
  95                if (err)
  96                        return err;
  97        }
  98
  99        shifted_cp = sign_extend32(val, 5);
 100
 101        shared->actual_temp_cp = 2 * NOMINAL_CALIB_CP + shifted_cp;
 102        shared->actual_temp_ft = 2 * NOMINAL_CALIB_FT + shifted_ft;
 103
 104        return 0;
 105}
 106
 107int tegra_calc_tsensor_calib(const struct tegra_tsensor *sensor,
 108                             const struct tsensor_shared_calib *shared,
 109                             u32 *calibration)
 110{
 111        const struct tegra_tsensor_group *sensor_group;
 112        u32 val, calib;
 113        s32 actual_tsensor_ft, actual_tsensor_cp;
 114        s32 delta_sens, delta_temp;
 115        s32 mult, div;
 116        s16 therma, thermb;
 117        s64 temp;
 118        int err;
 119
 120        sensor_group = sensor->group;
 121
 122        err = tegra_fuse_readl(sensor->calib_fuse_offset, &val);
 123        if (err)
 124                return err;
 125
 126        actual_tsensor_cp = (shared->base_cp * 64) + sign_extend32(val, 12);
 127        val = (val & FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK) >>
 128              FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT;
 129        actual_tsensor_ft = (shared->base_ft * 32) + sign_extend32(val, 12);
 130
 131        delta_sens = actual_tsensor_ft - actual_tsensor_cp;
 132        delta_temp = shared->actual_temp_ft - shared->actual_temp_cp;
 133
 134        mult = sensor_group->pdiv * sensor->config->tsample_ate;
 135        div = sensor->config->tsample * sensor_group->pdiv_ate;
 136
 137        temp = (s64)delta_temp * (1LL << 13) * mult;
 138        therma = div64_s64_precise(temp, (s64)delta_sens * div);
 139
 140        temp = ((s64)actual_tsensor_ft * shared->actual_temp_cp) -
 141                ((s64)actual_tsensor_cp * shared->actual_temp_ft);
 142        thermb = div64_s64_precise(temp, delta_sens);
 143
 144        temp = (s64)therma * sensor->fuse_corr_alpha;
 145        therma = div64_s64_precise(temp, CALIB_COEFFICIENT);
 146
 147        temp = (s64)thermb * sensor->fuse_corr_alpha + sensor->fuse_corr_beta;
 148        thermb = div64_s64_precise(temp, CALIB_COEFFICIENT);
 149
 150        calib = ((u16)therma << SENSOR_CONFIG2_THERMA_SHIFT) |
 151                ((u16)thermb << SENSOR_CONFIG2_THERMB_SHIFT);
 152
 153        *calibration = calib;
 154
 155        return 0;
 156}
 157
 158MODULE_AUTHOR("Wei Ni <wni@nvidia.com>");
 159MODULE_DESCRIPTION("Tegra SOCTHERM fuse management");
 160MODULE_LICENSE("GPL v2");
 161