drivers/thermal/qcom/tsens-common.c

   1 /*
   2  * Copyright (c) 2015, The Linux Foundation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 and
   6  * only version 2 as published by the Free Software Foundation.
   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/err.h>
  16 #include <linux/io.h>
  17 #include <linux/nvmem-consumer.h>
  18 #include <linux/of_address.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21 #include "tsens.h"
  22
  23 #define S0_ST_ADDR              0x1030
  24 #define SN_ADDR_OFFSET          0x4
  25 #define SN_ST_TEMP_MASK         0x3ff
  26 #define CAL_DEGC_PT1            30
  27 #define CAL_DEGC_PT2            120
  28 #define SLOPE_FACTOR            1000
  29 #define SLOPE_DEFAULT           3200
  30
  31 char *qfprom_read(struct device *dev, const char *cname)
  32 {
  33         struct nvmem_cell *cell;
  34         ssize_t data;
  35         char *ret;
  36
  37         cell = nvmem_cell_get(dev, cname);
  38         if (IS_ERR(cell))
  39                 return ERR_CAST(cell);
  40
  41         ret = nvmem_cell_read(cell, &data);
  42         nvmem_cell_put(cell);
  43
  44         return ret;
  45 }
  46
  47 /*
  48  * Use this function on devices where slope and offset calculations
  49  * depend on calibration data read from qfprom. On others the slope
  50  * and offset values are derived from tz->tzp->slope and tz->tzp->offset
  51  * resp.
  52  */
  53 void compute_intercept_slope(struct tsens_device *tmdev, u32 *p1,
  54                              u32 *p2, u32 mode)
  55 {
  56         int i;
  57         int num, den;
  58
  59         for (i = 0; i < tmdev->num_sensors; i++) {
  60                 dev_dbg(tmdev->dev,
  61                         "sensor%d - data_point1:%#x data_point2:%#x\n",
  62                         i, p1[i], p2[i]);
  63
  64                 tmdev->sensor[i].slope = SLOPE_DEFAULT;
  65                 if (mode == TWO_PT_CALIB) {
  66                         /*
  67                          * slope (m) = adc_code2 - adc_code1 (y2 - y1)/
  68                          *      temp_120_degc - temp_30_degc (x2 - x1)
  69                          */
  70                         num = p2[i] - p1[i];
  71                         num *= SLOPE_FACTOR;
  72                         den = CAL_DEGC_PT2 - CAL_DEGC_PT1;
  73                         tmdev->sensor[i].slope = num / den;
  74                 }
  75
  76                 tmdev->sensor[i].offset = (p1[i] * SLOPE_FACTOR) -
  77                                 (CAL_DEGC_PT1 *
  78                                 tmdev->sensor[i].slope);
  79                 dev_dbg(tmdev->dev, "offset:%d\n", tmdev->sensor[i].offset);
  80         }
  81 }
  82
  83 static inline int code_to_degc(u32 adc_code, const struct tsens_sensor *s)
  84 {
  85         int degc, num, den;
  86
  87         num = (adc_code * SLOPE_FACTOR) - s->offset;
  88         den = s->slope;
  89
  90         if (num > 0)
  91                 degc = num + (den / 2);
  92         else if (num < 0)
  93                 degc = num - (den / 2);
  94         else
  95                 degc = num;
  96
  97         degc /= den;
  98
  99         return degc;
 100 }
 101
 102 int get_temp_common(struct tsens_device *tmdev, int id, int *temp)
 103 {
 104         struct tsens_sensor *s = &tmdev->sensor[id];
 105         u32 code;
 106         unsigned int sensor_addr;
 107         int last_temp = 0, ret;
 108
 109         sensor_addr = S0_ST_ADDR + s->hw_id * SN_ADDR_OFFSET;
 110         ret = regmap_read(tmdev->map, sensor_addr, &code);
 111         if (ret)
 112                 return ret;
 113         last_temp = code & SN_ST_TEMP_MASK;
 114
 115         *temp = code_to_degc(last_temp, s) * 1000;
 116
 117         return 0;
 118 }
 119
 120 static const struct regmap_config tsens_config = {
 121         .reg_bits       = 32,
 122         .val_bits       = 32,
 123         .reg_stride     = 4,
 124 };
 125
 126 int __init init_common(struct tsens_device *tmdev)
 127 {
 128         void __iomem *base;
 129
 130         base = of_iomap(tmdev->dev->of_node, 0);
 131         if (!base)
 132                 return -EINVAL;
 133
 134         tmdev->map = devm_regmap_init_mmio(tmdev->dev, base, &tsens_config);
 135         if (IS_ERR(tmdev->map)) {
 136                 iounmap(base);
 137                 return PTR_ERR(tmdev->map);
 138         }
 139
 140         return 0;
 141 }