drivers/iio/adc/qcom-vadc-common.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/bug.h>
   3 #include <linux/kernel.h>
   4 #include <linux/bitops.h>
   5 #include <linux/math64.h>
   6 #include <linux/log2.h>
   7 #include <linux/err.h>
   8
   9 #include "qcom-vadc-common.h"
  10
  11 /* Voltage to temperature */
  12 static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
  13         {1758,  -40},
  14         {1742,  -35},
  15         {1719,  -30},
  16         {1691,  -25},
  17         {1654,  -20},
  18         {1608,  -15},
  19         {1551,  -10},
  20         {1483,  -5},
  21         {1404,  0},
  22         {1315,  5},
  23         {1218,  10},
  24         {1114,  15},
  25         {1007,  20},
  26         {900,   25},
  27         {795,   30},
  28         {696,   35},
  29         {605,   40},
  30         {522,   45},
  31         {448,   50},
  32         {383,   55},
  33         {327,   60},
  34         {278,   65},
  35         {237,   70},
  36         {202,   75},
  37         {172,   80},
  38         {146,   85},
  39         {125,   90},
  40         {107,   95},
  41         {92,    100},
  42         {79,    105},
  43         {68,    110},
  44         {59,    115},
  45         {51,    120},
  46         {44,    125}
  47 };
  48
  49 static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
  50                                       u32 tablesize, s32 input, s64 *output)
  51 {
  52         bool descending = 1;
  53         u32 i = 0;
  54
  55         if (!pts)
  56                 return -EINVAL;
  57
  58         /* Check if table is descending or ascending */
  59         if (tablesize > 1) {
  60                 if (pts[0].x < pts[1].x)
  61                         descending = 0;
  62         }
  63
  64         while (i < tablesize) {
  65                 if ((descending) && (pts[i].x < input)) {
  66                         /* table entry is less than measured*/
  67                          /* value and table is descending, stop */
  68                         break;
  69                 } else if ((!descending) &&
  70                                 (pts[i].x > input)) {
  71                         /* table entry is greater than measured*/
  72                         /*value and table is ascending, stop */
  73                         break;
  74                 }
  75                 i++;
  76         }
  77
  78         if (i == 0) {
  79                 *output = pts[0].y;
  80         } else if (i == tablesize) {
  81                 *output = pts[tablesize - 1].y;
  82         } else {
  83                 /* result is between search_index and search_index-1 */
  84                 /* interpolate linearly */
  85                 *output = (((s32)((pts[i].y - pts[i - 1].y) *
  86                         (input - pts[i - 1].x)) /
  87                         (pts[i].x - pts[i - 1].x)) +
  88                         pts[i - 1].y);
  89         }
  90
  91         return 0;
  92 }
  93
  94 static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,
  95                                   u16 adc_code,
  96                                   bool absolute,
  97                                   s64 *scale_voltage)
  98 {
  99         *scale_voltage = (adc_code - calib_graph->gnd);
 100         *scale_voltage *= calib_graph->dx;
 101         *scale_voltage = div64_s64(*scale_voltage, calib_graph->dy);
 102         if (absolute)
 103                 *scale_voltage += calib_graph->dx;
 104
 105         if (*scale_voltage < 0)
 106                 *scale_voltage = 0;
 107 }
 108
 109 static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,
 110                                 const struct vadc_prescale_ratio *prescale,
 111                                 bool absolute, u16 adc_code,
 112                                 int *result_uv)
 113 {
 114         s64 voltage = 0, result = 0;
 115
 116         qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
 117
 118         voltage = voltage * prescale->den;
 119         result = div64_s64(voltage, prescale->num);
 120         *result_uv = result;
 121
 122         return 0;
 123 }
 124
 125 static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
 126                                  const struct vadc_prescale_ratio *prescale,
 127                                  bool absolute, u16 adc_code,
 128                                  int *result_mdec)
 129 {
 130         s64 voltage = 0, result = 0;
 131         int ret;
 132
 133         qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
 134
 135         if (absolute)
 136                 voltage = div64_s64(voltage, 1000);
 137
 138         ret = qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
 139                                          ARRAY_SIZE(adcmap_100k_104ef_104fb),
 140                                          voltage, &result);
 141         if (ret)
 142                 return ret;
 143
 144         result *= 1000;
 145         *result_mdec = result;
 146
 147         return 0;
 148 }
 149
 150 static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,
 151                                     const struct vadc_prescale_ratio *prescale,
 152                                     bool absolute,
 153                                     u16 adc_code, int *result_mdec)
 154 {
 155         s64 voltage = 0;
 156         u64 temp; /* Temporary variable for do_div */
 157
 158         qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
 159
 160         if (voltage > 0) {
 161                 temp = voltage * prescale->den;
 162                 do_div(temp, prescale->num * 2);
 163                 voltage = temp;
 164         } else {
 165                 voltage = 0;
 166         }
 167
 168         voltage -= KELVINMIL_CELSIUSMIL;
 169         *result_mdec = voltage;
 170
 171         return 0;
 172 }
 173
 174 static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
 175                                     const struct vadc_prescale_ratio *prescale,
 176                                     bool absolute,
 177                                     u16 adc_code, int *result_mdec)
 178 {
 179         s64 voltage = 0, result = 0;
 180
 181         qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
 182
 183         voltage = voltage * prescale->den;
 184         voltage = div64_s64(voltage, prescale->num);
 185         voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
 186         voltage = (voltage + PMI_CHG_SCALE_2);
 187         result =  div64_s64(voltage, 1000000);
 188         *result_mdec = result;
 189
 190         return 0;
 191 }
 192
 193 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 194                     const struct vadc_linear_graph *calib_graph,
 195                     const struct vadc_prescale_ratio *prescale,
 196                     bool absolute,
 197                     u16 adc_code, int *result)
 198 {
 199         switch (scaletype) {
 200         case SCALE_DEFAULT:
 201                 return qcom_vadc_scale_volt(calib_graph, prescale,
 202                                             absolute, adc_code,
 203                                             result);
 204         case SCALE_THERM_100K_PULLUP:
 205         case SCALE_XOTHERM:
 206                 return qcom_vadc_scale_therm(calib_graph, prescale,
 207                                              absolute, adc_code,
 208                                              result);
 209         case SCALE_PMIC_THERM:
 210                 return qcom_vadc_scale_die_temp(calib_graph, prescale,
 211                                                 absolute, adc_code,
 212                                                 result);
 213         case SCALE_PMI_CHG_TEMP:
 214                 return qcom_vadc_scale_chg_temp(calib_graph, prescale,
 215                                                 absolute, adc_code,
 216                                                 result);
 217         default:
 218                 return -EINVAL;
 219         }
 220 }
 221 EXPORT_SYMBOL(qcom_vadc_scale);
 222
 223 int qcom_vadc_decimation_from_dt(u32 value)
 224 {
 225         if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
 226             value > VADC_DECIMATION_MAX)
 227                 return -EINVAL;
 228
 229         return __ffs64(value / VADC_DECIMATION_MIN);
 230 }
 231 EXPORT_SYMBOL(qcom_vadc_decimation_from_dt);