1/* 2 * Nokia RX-51 battery driver 3 * 4 * Copyright (C) 2012 Pali Rohár <pali.rohar@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License along 17 * with this program; if not, write to the Free Software Foundation, Inc., 18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 19 */ 20 21#include <linux/module.h> 22#include <linux/param.h> 23#include <linux/platform_device.h> 24#include <linux/power_supply.h> 25#include <linux/slab.h> 26#include <linux/i2c/twl4030-madc.h> 27#include <linux/iio/consumer.h> 28#include <linux/of.h> 29 30struct rx51_device_info { 31 struct device *dev; 32 struct power_supply bat; 33 struct iio_channel *channel_temp; 34 struct iio_channel *channel_bsi; 35 struct iio_channel *channel_vbat; 36}; 37 38/* 39 * Read ADCIN channel value, code copied from maemo kernel 40 */ 41static int rx51_battery_read_adc(struct iio_channel *channel) 42{ 43 int val, err; 44 err = iio_read_channel_average_raw(channel, &val); 45 if (err < 0) 46 return err; 47 return val; 48} 49 50/* 51 * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage 52 * This conversion formula was extracted from maemo program bsi-read 53 */ 54static int rx51_battery_read_voltage(struct rx51_device_info *di) 55{ 56 int voltage = rx51_battery_read_adc(di->channel_vbat); 57 58 if (voltage < 0) { 59 dev_err(di->dev, "Could not read ADC: %d\n", voltage); 60 return voltage; 61 } 62 63 return 1000 * (10000 * voltage / 1705); 64} 65 66/* 67 * Temperature look-up tables 68 * TEMP = (1/(t1 + 1/298) - 273.15) 69 * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255)) 70 * Formula is based on experimental data, RX-51 CAL data, maemo program bme 71 * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671 72 */ 73 74/* 75 * Table1 (temperature for first 25 RAW values) 76 * Usage: TEMP = rx51_temp_table1[RAW] 77 * RAW is between 1 and 24 78 * TEMP is between 201 C and 55 C 79 */ 80static u8 rx51_temp_table1[] = { 81 255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75, 82 73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55 83}; 84 85/* 86 * Table2 (lowest RAW value for temperature) 87 * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first] 88 * TEMP is between 53 C and -32 C 89 * RAW is between 25 and 993 90 */ 91#define rx51_temp_table2_first 53 92static u16 rx51_temp_table2[] = { 93 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, 94 40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64, 95 66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110, 96 115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211, 97 221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415, 98 437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885, 99 937, 993, 1024 100}; 101 102/* 103 * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius 104 * Use Temperature look-up tables for conversation 105 */ 106static int rx51_battery_read_temperature(struct rx51_device_info *di) 107{ 108 int min = 0; 109 int max = ARRAY_SIZE(rx51_temp_table2) - 1; 110 int raw = rx51_battery_read_adc(di->channel_temp); 111 112 if (raw < 0) 113 dev_err(di->dev, "Could not read ADC: %d\n", raw); 114 115 /* Zero and negative values are undefined */ 116 if (raw <= 0) 117 return INT_MAX; 118 119 /* ADC channels are 10 bit, higher value are undefined */ 120 if (raw >= (1 << 10)) 121 return INT_MIN; 122 123 /* First check for temperature in first direct table */ 124 if (raw < ARRAY_SIZE(rx51_temp_table1)) 125 return rx51_temp_table1[raw] * 10; 126 127 /* Binary search RAW value in second inverse table */ 128 while (max - min > 1) { 129 int mid = (max + min) / 2; 130 if (rx51_temp_table2[mid] <= raw) 131 min = mid; 132 else if (rx51_temp_table2[mid] > raw) 133 max = mid; 134 if (rx51_temp_table2[mid] == raw) 135 break; 136 } 137 138 return (rx51_temp_table2_first - min) * 10; 139} 140 141/* 142 * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah 143 * This conversion formula was extracted from maemo program bsi-read 144 */ 145static int rx51_battery_read_capacity(struct rx51_device_info *di) 146{ 147 int capacity = rx51_battery_read_adc(di->channel_bsi); 148 149 if (capacity < 0) { 150 dev_err(di->dev, "Could not read ADC: %d\n", capacity); 151 return capacity; 152 } 153 154 return 1280 * (1200 * capacity)/(1024 - capacity); 155} 156 157/* 158 * Return power_supply property 159 */ 160static int rx51_battery_get_property(struct power_supply *psy, 161 enum power_supply_property psp, 162 union power_supply_propval *val) 163{ 164 struct rx51_device_info *di = container_of((psy), 165 struct rx51_device_info, bat); 166 167 switch (psp) { 168 case POWER_SUPPLY_PROP_TECHNOLOGY: 169 val->intval = POWER_SUPPLY_TECHNOLOGY_LION; 170 break; 171 case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN: 172 val->intval = 4200000; 173 break; 174 case POWER_SUPPLY_PROP_PRESENT: 175 val->intval = rx51_battery_read_voltage(di) ? 1 : 0; 176 break; 177 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 178 val->intval = rx51_battery_read_voltage(di); 179 break; 180 case POWER_SUPPLY_PROP_TEMP: 181 val->intval = rx51_battery_read_temperature(di); 182 break; 183 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: 184 val->intval = rx51_battery_read_capacity(di); 185 break; 186 default: 187 return -EINVAL; 188 } 189 190 if (val->intval == INT_MAX || val->intval == INT_MIN) 191 return -EINVAL; 192 193 return 0; 194} 195 196static enum power_supply_property rx51_battery_props[] = { 197 POWER_SUPPLY_PROP_TECHNOLOGY, 198 POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 199 POWER_SUPPLY_PROP_PRESENT, 200 POWER_SUPPLY_PROP_VOLTAGE_NOW, 201 POWER_SUPPLY_PROP_TEMP, 202 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 203}; 204 205static int rx51_battery_probe(struct platform_device *pdev) 206{ 207 struct rx51_device_info *di; 208 int ret; 209 210 di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL); 211 if (!di) 212 return -ENOMEM; 213 214 platform_set_drvdata(pdev, di); 215 216 di->dev = &pdev->dev; 217 di->bat.name = dev_name(&pdev->dev); 218 di->bat.type = POWER_SUPPLY_TYPE_BATTERY; 219 di->bat.properties = rx51_battery_props; 220 di->bat.num_properties = ARRAY_SIZE(rx51_battery_props); 221 di->bat.get_property = rx51_battery_get_property; 222 223 di->channel_temp = iio_channel_get(di->dev, "temp"); 224 if (IS_ERR(di->channel_temp)) { 225 ret = PTR_ERR(di->channel_temp); 226 goto error; 227 } 228 229 di->channel_bsi = iio_channel_get(di->dev, "bsi"); 230 if (IS_ERR(di->channel_bsi)) { 231 ret = PTR_ERR(di->channel_bsi); 232 goto error_channel_temp; 233 } 234 235 di->channel_vbat = iio_channel_get(di->dev, "vbat"); 236 if (IS_ERR(di->channel_vbat)) { 237 ret = PTR_ERR(di->channel_vbat); 238 goto error_channel_bsi; 239 } 240 241 ret = power_supply_register(di->dev, &di->bat); 242 if (ret) 243 goto error_channel_vbat; 244 245 return 0; 246 247error_channel_vbat: 248 iio_channel_release(di->channel_vbat); 249error_channel_bsi: 250 iio_channel_release(di->channel_bsi); 251error_channel_temp: 252 iio_channel_release(di->channel_temp); 253error: 254 255 return ret; 256} 257 258static int rx51_battery_remove(struct platform_device *pdev) 259{ 260 struct rx51_device_info *di = platform_get_drvdata(pdev); 261 262 power_supply_unregister(&di->bat); 263 264 iio_channel_release(di->channel_vbat); 265 iio_channel_release(di->channel_bsi); 266 iio_channel_release(di->channel_temp); 267 268 return 0; 269} 270 271#ifdef CONFIG_OF 272static const struct of_device_id n900_battery_of_match[] = { 273 {.compatible = "nokia,n900-battery", }, 274 { }, 275}; 276MODULE_DEVICE_TABLE(of, n900_battery_of_match); 277#endif 278 279static struct platform_driver rx51_battery_driver = { 280 .probe = rx51_battery_probe, 281 .remove = rx51_battery_remove, 282 .driver = { 283 .name = "rx51-battery", 284 .owner = THIS_MODULE, 285 .of_match_table = of_match_ptr(n900_battery_of_match), 286 }, 287}; 288module_platform_driver(rx51_battery_driver); 289 290MODULE_ALIAS("platform:rx51-battery"); 291MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>"); 292MODULE_DESCRIPTION("Nokia RX-51 battery driver"); 293MODULE_LICENSE("GPL"); 294