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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Nokia RX-51 battery driver4 *5 * Copyright (C) 2012 Pali Rohár <pali@kernel.org>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 16struct 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 kernel27 */28static 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 voltage39 * This conversion formula was extracted from maemo program bsi-read40 */41static 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 tables55 * 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 bme58 * and formula from da9052 driver with values R = 100, B = 3380, I = 0.0067159 */60 61/*62 * Table1 (temperature for first 25 RAW values)63 * Usage: TEMP = rx51_temp_table1[RAW]64 * RAW is between 1 and 2465 * TEMP is between 201 C and 55 C66 */67static 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, 5570};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 C76 * RAW is between 25 and 99377 */78#define rx51_temp_table2_first 5379static 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, 102487};88 89/*90 * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius91 * Use Temperature look-up tables for conversation92 */93static 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 Ah130 * This conversion formula was extracted from maemo program bsi-read131 */132static 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 property146 */147static 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 182static 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 191static int rx51_battery_probe(struct platform_device *pdev)192{193 struct power_supply_config psy_cfg = {};194 struct rx51_device_info *di;195 196 di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);197 if (!di)198 return -ENOMEM;199 200 di->dev = &pdev->dev;201 di->bat_desc.name = "rx51-battery";202 di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;203 di->bat_desc.properties = rx51_battery_props;204 di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props);205 di->bat_desc.get_property = rx51_battery_get_property;206 207 psy_cfg.drv_data = di;208 209 di->channel_temp = devm_iio_channel_get(di->dev, "temp");210 if (IS_ERR(di->channel_temp))211 return PTR_ERR(di->channel_temp);212 213 di->channel_bsi = devm_iio_channel_get(di->dev, "bsi");214 if (IS_ERR(di->channel_bsi))215 return PTR_ERR(di->channel_bsi);216 217 di->channel_vbat = devm_iio_channel_get(di->dev, "vbat");218 if (IS_ERR(di->channel_vbat))219 return PTR_ERR(di->channel_vbat);220 221 di->bat = devm_power_supply_register(di->dev, &di->bat_desc, &psy_cfg);222 if (IS_ERR(di->bat))223 return PTR_ERR(di->bat);224 225 return 0;226}227 228#ifdef CONFIG_OF229static const struct of_device_id n900_battery_of_match[] = {230 {.compatible = "nokia,n900-battery", },231 { },232};233MODULE_DEVICE_TABLE(of, n900_battery_of_match);234#endif235 236static struct platform_driver rx51_battery_driver = {237 .probe = rx51_battery_probe,238 .driver = {239 .name = "rx51-battery",240 .of_match_table = of_match_ptr(n900_battery_of_match),241 },242};243module_platform_driver(rx51_battery_driver);244 245MODULE_ALIAS("platform:rx51-battery");246MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");247MODULE_DESCRIPTION("Nokia RX-51 battery driver");248MODULE_LICENSE("GPL");249