drivers/power/supply/rx51_battery.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Nokia RX-51 battery driver
   4  *
   5  * Copyright (C) 2012  Pali Rohár <pali.rohar@gmail.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/param.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/power_supply.h>
  12 #include <linux/slab.h>
  13 #include <linux/iio/consumer.h>
  14 #include <linux/of.h>
  15
  16 struct rx51_device_info {
  17         struct device *dev;
  18         struct power_supply *bat;
  19         struct power_supply_desc bat_desc;
  20         struct iio_channel *channel_temp;
  21         struct iio_channel *channel_bsi;
  22         struct iio_channel *channel_vbat;
  23 };
  24
  25 /*
  26  * Read ADCIN channel value, code copied from maemo kernel
  27  */
  28 static int rx51_battery_read_adc(struct iio_channel *channel)
  29 {
  30         int val, err;
  31         err = iio_read_channel_average_raw(channel, &val);
  32         if (err < 0)
  33                 return err;
  34         return val;
  35 }
  36
  37 /*
  38  * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage
  39  * This conversion formula was extracted from maemo program bsi-read
  40  */
  41 static int rx51_battery_read_voltage(struct rx51_device_info *di)
  42 {
  43         int voltage = rx51_battery_read_adc(di->channel_vbat);
  44
  45         if (voltage < 0) {
  46                 dev_err(di->dev, "Could not read ADC: %d\n", voltage);
  47                 return voltage;
  48         }
  49
  50         return 1000 * (10000 * voltage / 1705);
  51 }
  52
  53 /*
  54  * Temperature look-up tables
  55  * TEMP = (1/(t1 + 1/298) - 273.15)
  56  * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255))
  57  * Formula is based on experimental data, RX-51 CAL data, maemo program bme
  58  * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671
  59  */
  60
  61 /*
  62  * Table1 (temperature for first 25 RAW values)
  63  * Usage: TEMP = rx51_temp_table1[RAW]
  64  *   RAW is between 1 and 24
  65  *   TEMP is between 201 C and 55 C
  66  */
  67 static u8 rx51_temp_table1[] = {
  68         255, 201, 159, 138, 124, 114, 106,  99,  94,  89,  85,  82,  78,  75,
  69          73,  70,  68,  66,  64,  62,  61,  59,  57,  56,  55
  70 };
  71
  72 /*
  73  * Table2 (lowest RAW value for temperature)
  74  * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first]
  75  *   TEMP is between 53 C and -32 C
  76  *   RAW is between 25 and 993
  77  */
  78 #define rx51_temp_table2_first 53
  79 static u16 rx51_temp_table2[] = {
  80          25,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  39,
  81          40,  41,  43,  44,  46,  48,  49,  51,  53,  55,  57,  59,  61,  64,
  82          66,  69,  71,  74,  77,  80,  83,  86,  90,  94,  97, 101, 106, 110,
  83         115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211,
  84         221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415,
  85         437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885,
  86         937, 993, 1024
  87 };
  88
  89 /*
  90  * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius
  91  * Use Temperature look-up tables for conversation
  92  */
  93 static int rx51_battery_read_temperature(struct rx51_device_info *di)
  94 {
  95         int min = 0;
  96         int max = ARRAY_SIZE(rx51_temp_table2) - 1;
  97         int raw = rx51_battery_read_adc(di->channel_temp);
  98
  99         if (raw < 0)
 100                 dev_err(di->dev, "Could not read ADC: %d\n", raw);
 101
 102         /* Zero and negative values are undefined */
 103         if (raw <= 0)
 104                 return INT_MAX;
 105
 106         /* ADC channels are 10 bit, higher value are undefined */
 107         if (raw >= (1 << 10))
 108                 return INT_MIN;
 109
 110         /* First check for temperature in first direct table */
 111         if (raw < ARRAY_SIZE(rx51_temp_table1))
 112                 return rx51_temp_table1[raw] * 10;
 113
 114         /* Binary search RAW value in second inverse table */
 115         while (max - min > 1) {
 116                 int mid = (max + min) / 2;
 117                 if (rx51_temp_table2[mid] <= raw)
 118                         min = mid;
 119                 else if (rx51_temp_table2[mid] > raw)
 120                         max = mid;
 121                 if (rx51_temp_table2[mid] == raw)
 122                         break;
 123         }
 124
 125         return (rx51_temp_table2_first - min) * 10;
 126 }
 127
 128 /*
 129  * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah
 130  * This conversion formula was extracted from maemo program bsi-read
 131  */
 132 static int rx51_battery_read_capacity(struct rx51_device_info *di)
 133 {
 134         int capacity = rx51_battery_read_adc(di->channel_bsi);
 135
 136         if (capacity < 0) {
 137                 dev_err(di->dev, "Could not read ADC: %d\n", capacity);
 138                 return capacity;
 139         }
 140
 141         return 1280 * (1200 * capacity)/(1024 - capacity);
 142 }
 143
 144 /*
 145  * Return power_supply property
 146  */
 147 static int rx51_battery_get_property(struct power_supply *psy,
 148                                         enum power_supply_property psp,
 149                                         union power_supply_propval *val)
 150 {
 151         struct rx51_device_info *di = power_supply_get_drvdata(psy);
 152
 153         switch (psp) {
 154         case POWER_SUPPLY_PROP_TECHNOLOGY:
 155                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 156                 break;
 157         case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
 158                 val->intval = 4200000;
 159                 break;
 160         case POWER_SUPPLY_PROP_PRESENT:
 161                 val->intval = rx51_battery_read_voltage(di) ? 1 : 0;
 162                 break;
 163         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 164                 val->intval = rx51_battery_read_voltage(di);
 165                 break;
 166         case POWER_SUPPLY_PROP_TEMP:
 167                 val->intval = rx51_battery_read_temperature(di);
 168                 break;
 169         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 170                 val->intval = rx51_battery_read_capacity(di);
 171                 break;
 172         default:
 173                 return -EINVAL;
 174         }
 175
 176         if (val->intval == INT_MAX || val->intval == INT_MIN)
 177                 return -EINVAL;
 178
 179         return 0;
 180 }
 181
 182 static enum power_supply_property rx51_battery_props[] = {
 183         POWER_SUPPLY_PROP_TECHNOLOGY,
 184         POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
 185         POWER_SUPPLY_PROP_PRESENT,
 186         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 187         POWER_SUPPLY_PROP_TEMP,
 188         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 189 };
 190
 191 static int rx51_battery_probe(struct platform_device *pdev)
 192 {
 193         struct power_supply_config psy_cfg = {};
 194         struct rx51_device_info *di;
 195         int ret;
 196
 197         di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);
 198         if (!di)
 199                 return -ENOMEM;
 200
 201         platform_set_drvdata(pdev, di);
 202
 203         di->dev = &pdev->dev;
 204         di->bat_desc.name = "rx51-battery";
 205         di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 206         di->bat_desc.properties = rx51_battery_props;
 207         di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props);
 208         di->bat_desc.get_property = rx51_battery_get_property;
 209
 210         psy_cfg.drv_data = di;
 211
 212         di->channel_temp = iio_channel_get(di->dev, "temp");
 213         if (IS_ERR(di->channel_temp)) {
 214                 ret = PTR_ERR(di->channel_temp);
 215                 goto error;
 216         }
 217
 218         di->channel_bsi  = iio_channel_get(di->dev, "bsi");
 219         if (IS_ERR(di->channel_bsi)) {
 220                 ret = PTR_ERR(di->channel_bsi);
 221                 goto error_channel_temp;
 222         }
 223
 224         di->channel_vbat = iio_channel_get(di->dev, "vbat");
 225         if (IS_ERR(di->channel_vbat)) {
 226                 ret = PTR_ERR(di->channel_vbat);
 227                 goto error_channel_bsi;
 228         }
 229
 230         di->bat = power_supply_register(di->dev, &di->bat_desc, &psy_cfg);
 231         if (IS_ERR(di->bat)) {
 232                 ret = PTR_ERR(di->bat);
 233                 goto error_channel_vbat;
 234         }
 235
 236         return 0;
 237
 238 error_channel_vbat:
 239         iio_channel_release(di->channel_vbat);
 240 error_channel_bsi:
 241         iio_channel_release(di->channel_bsi);
 242 error_channel_temp:
 243         iio_channel_release(di->channel_temp);
 244 error:
 245
 246         return ret;
 247 }
 248
 249 static int rx51_battery_remove(struct platform_device *pdev)
 250 {
 251         struct rx51_device_info *di = platform_get_drvdata(pdev);
 252
 253         power_supply_unregister(di->bat);
 254
 255         iio_channel_release(di->channel_vbat);
 256         iio_channel_release(di->channel_bsi);
 257         iio_channel_release(di->channel_temp);
 258
 259         return 0;
 260 }
 261
 262 #ifdef CONFIG_OF
 263 static const struct of_device_id n900_battery_of_match[] = {
 264         {.compatible = "nokia,n900-battery", },
 265         { },
 266 };
 267 MODULE_DEVICE_TABLE(of, n900_battery_of_match);
 268 #endif
 269
 270 static struct platform_driver rx51_battery_driver = {
 271         .probe = rx51_battery_probe,
 272         .remove = rx51_battery_remove,
 273         .driver = {
 274                 .name = "rx51-battery",
 275                 .of_match_table = of_match_ptr(n900_battery_of_match),
 276         },
 277 };
 278 module_platform_driver(rx51_battery_driver);
 279
 280 MODULE_ALIAS("platform:rx51-battery");
 281 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 282 MODULE_DESCRIPTION("Nokia RX-51 battery driver");
 283 MODULE_LICENSE("GPL");