drivers/thermal/tegra/soctherm-fuse.c

   1 /*
   2  * Copyright (c) 2014-2016, NVIDIA CORPORATION.  All rights reserved.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <soc/tegra/fuse.h>
  18
  19 #include "soctherm.h"
  20
  21 #define NOMINAL_CALIB_FT                        105
  22 #define NOMINAL_CALIB_CP                        25
  23
  24 #define FUSE_TSENSOR_CALIB_CP_TS_BASE_MASK      0x1fff
  25 #define FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK      (0x1fff << 13)
  26 #define FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT     13
  27
  28 #define FUSE_TSENSOR_COMMON                     0x180
  29
  30 /*
  31  * Tegra210: Layout of bits in FUSE_TSENSOR_COMMON:
  32  *    3                   2                   1                   0
  33  *  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
  34  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  * |       BASE_FT       |      BASE_CP      | SHFT_FT | SHIFT_CP  |
  36  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *
  38  * Tegra12x, etc:
  39  * In chips prior to Tegra210, this fuse was incorrectly sized as 26 bits,
  40  * and didn't hold SHIFT_CP in [31:26]. Therefore these missing six bits
  41  * were obtained via the FUSE_SPARE_REALIGNMENT_REG register [5:0].
  42  *
  43  * FUSE_TSENSOR_COMMON:
  44  *    3                   2                   1                   0
  45  *  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
  46  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47  * |-----------| SHFT_FT |       BASE_FT       |      BASE_CP      |
  48  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  49  *
  50  * FUSE_SPARE_REALIGNMENT_REG:
  51  *    3                   2                   1                   0
  52  *  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
  53  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54  * |---------------------------------------------------| SHIFT_CP  |
  55  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56  */
  57
  58 #define CALIB_COEFFICIENT 1000000LL
  59
  60 /**
  61  * div64_s64_precise() - wrapper for div64_s64()
  62  * @a:  the dividend
  63  * @b:  the divisor
  64  *
  65  * Implements division with fairly accurate rounding instead of truncation by
  66  * shifting the dividend to the left by 16 so that the quotient has a
  67  * much higher precision.
  68  *
  69  * Return: the quotient of a / b.
  70  */
  71 static s64 div64_s64_precise(s64 a, s32 b)
  72 {
  73         s64 r, al;
  74
  75         /* Scale up for increased precision division */
  76         al = a << 16;
  77
  78         r = div64_s64(al * 2 + 1, 2 * b);
  79         return r >> 16;
  80 }
  81
  82 int tegra_calc_shared_calib(const struct tegra_soctherm_fuse *tfuse,
  83                             struct tsensor_shared_calib *shared)
  84 {
  85         u32 val;
  86         s32 shifted_cp, shifted_ft;
  87         int err;
  88
  89         err = tegra_fuse_readl(FUSE_TSENSOR_COMMON, &val);
  90         if (err)
  91                 return err;
  92
  93         shared->base_cp = (val & tfuse->fuse_base_cp_mask) >>
  94                           tfuse->fuse_base_cp_shift;
  95         shared->base_ft = (val & tfuse->fuse_base_ft_mask) >>
  96                           tfuse->fuse_base_ft_shift;
  97
  98         shifted_ft = (val & tfuse->fuse_shift_ft_mask) >>
  99                      tfuse->fuse_shift_ft_shift;
 100         shifted_ft = sign_extend32(shifted_ft, 4);
 101
 102         if (tfuse->fuse_spare_realignment) {
 103                 err = tegra_fuse_readl(tfuse->fuse_spare_realignment, &val);
 104                 if (err)
 105                         return err;
 106         }
 107
 108         shifted_cp = sign_extend32(val, 5);
 109
 110         shared->actual_temp_cp = 2 * NOMINAL_CALIB_CP + shifted_cp;
 111         shared->actual_temp_ft = 2 * NOMINAL_CALIB_FT + shifted_ft;
 112
 113         return 0;
 114 }
 115
 116 int tegra_calc_tsensor_calib(const struct tegra_tsensor *sensor,
 117                              const struct tsensor_shared_calib *shared,
 118                              u32 *calibration)
 119 {
 120         const struct tegra_tsensor_group *sensor_group;
 121         u32 val, calib;
 122         s32 actual_tsensor_ft, actual_tsensor_cp;
 123         s32 delta_sens, delta_temp;
 124         s32 mult, div;
 125         s16 therma, thermb;
 126         s64 temp;
 127         int err;
 128
 129         sensor_group = sensor->group;
 130
 131         err = tegra_fuse_readl(sensor->calib_fuse_offset, &val);
 132         if (err)
 133                 return err;
 134
 135         actual_tsensor_cp = (shared->base_cp * 64) + sign_extend32(val, 12);
 136         val = (val & FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK) >>
 137               FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT;
 138         actual_tsensor_ft = (shared->base_ft * 32) + sign_extend32(val, 12);
 139
 140         delta_sens = actual_tsensor_ft - actual_tsensor_cp;
 141         delta_temp = shared->actual_temp_ft - shared->actual_temp_cp;
 142
 143         mult = sensor_group->pdiv * sensor->config->tsample_ate;
 144         div = sensor->config->tsample * sensor_group->pdiv_ate;
 145
 146         temp = (s64)delta_temp * (1LL << 13) * mult;
 147         therma = div64_s64_precise(temp, (s64)delta_sens * div);
 148
 149         temp = ((s64)actual_tsensor_ft * shared->actual_temp_cp) -
 150                 ((s64)actual_tsensor_cp * shared->actual_temp_ft);
 151         thermb = div64_s64_precise(temp, delta_sens);
 152
 153         temp = (s64)therma * sensor->fuse_corr_alpha;
 154         therma = div64_s64_precise(temp, CALIB_COEFFICIENT);
 155
 156         temp = (s64)thermb * sensor->fuse_corr_alpha + sensor->fuse_corr_beta;
 157         thermb = div64_s64_precise(temp, CALIB_COEFFICIENT);
 158
 159         calib = ((u16)therma << SENSOR_CONFIG2_THERMA_SHIFT) |
 160                 ((u16)thermb << SENSOR_CONFIG2_THERMB_SHIFT);
 161
 162         *calibration = calib;
 163
 164         return 0;
 165 }
 166
 167 MODULE_AUTHOR("Wei Ni <wni@nvidia.com>");
 168 MODULE_DESCRIPTION("Tegra SOCTHERM fuse management");
 169 MODULE_LICENSE("GPL v2");