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 power_supply_desc bat_desc; 34 struct iio_channel *channel_temp; 35 struct iio_channel *channel_bsi; 36 struct iio_channel *channel_vbat; 37}; 38 39/* 40 * Read ADCIN channel value, code copied from maemo kernel 41 */ 42static int rx51_battery_read_adc(struct iio_channel *channel) 43{ 44 int val, err; 45 err = iio_read_channel_average_raw(channel, &val); 46 if (err < 0) 47 return err; 48 return val; 49} 50 51/* 52 * Read ADCIN channel 12 (voltage) and convert RAW value to micro voltage 53 * This conversion formula was extracted from maemo program bsi-read 54 */ 55static int rx51_battery_read_voltage(struct rx51_device_info *di) 56{ 57 int voltage = rx51_battery_read_adc(di->channel_vbat); 58 59 if (voltage < 0) { 60 dev_err(di->dev, "Could not read ADC: %d\n", voltage); 61 return voltage; 62 } 63 64 return 1000 * (10000 * voltage / 1705); 65} 66 67/* 68 * Temperature look-up tables 69 * TEMP = (1/(t1 + 1/298) - 273.15) 70 * Where t1 = (1/B) * ln((RAW_ADC_U * 2.5)/(R * I * 255)) 71 * Formula is based on experimental data, RX-51 CAL data, maemo program bme 72 * and formula from da9052 driver with values R = 100, B = 3380, I = 0.00671 73 */ 74 75/* 76 * Table1 (temperature for first 25 RAW values) 77 * Usage: TEMP = rx51_temp_table1[RAW] 78 * RAW is between 1 and 24 79 * TEMP is between 201 C and 55 C 80 */ 81static u8 rx51_temp_table1[] = { 82 255, 201, 159, 138, 124, 114, 106, 99, 94, 89, 85, 82, 78, 75, 83 73, 70, 68, 66, 64, 62, 61, 59, 57, 56, 55 84}; 85 86/* 87 * Table2 (lowest RAW value for temperature) 88 * Usage: RAW = rx51_temp_table2[TEMP-rx51_temp_table2_first] 89 * TEMP is between 53 C and -32 C 90 * RAW is between 25 and 993 91 */ 92#define rx51_temp_table2_first 53 93static u16 rx51_temp_table2[] = { 94 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 39, 95 40, 41, 43, 44, 46, 48, 49, 51, 53, 55, 57, 59, 61, 64, 96 66, 69, 71, 74, 77, 80, 83, 86, 90, 94, 97, 101, 106, 110, 97 115, 119, 125, 130, 136, 141, 148, 154, 161, 168, 176, 184, 202, 211, 98 221, 231, 242, 254, 266, 279, 293, 308, 323, 340, 357, 375, 395, 415, 99 437, 460, 485, 511, 539, 568, 600, 633, 669, 706, 747, 790, 836, 885, 100 937, 993, 1024 101}; 102 103/* 104 * Read ADCIN channel 0 (battery temp) and convert value to tenths of Celsius 105 * Use Temperature look-up tables for conversation 106 */ 107static int rx51_battery_read_temperature(struct rx51_device_info *di) 108{ 109 int min = 0; 110 int max = ARRAY_SIZE(rx51_temp_table2) - 1; 111 int raw = rx51_battery_read_adc(di->channel_temp); 112 113 if (raw < 0) 114 dev_err(di->dev, "Could not read ADC: %d\n", raw); 115 116 /* Zero and negative values are undefined */ 117 if (raw <= 0) 118 return INT_MAX; 119 120 /* ADC channels are 10 bit, higher value are undefined */ 121 if (raw >= (1 << 10)) 122 return INT_MIN; 123 124 /* First check for temperature in first direct table */ 125 if (raw < ARRAY_SIZE(rx51_temp_table1)) 126 return rx51_temp_table1[raw] * 10; 127 128 /* Binary search RAW value in second inverse table */ 129 while (max - min > 1) { 130 int mid = (max + min) / 2; 131 if (rx51_temp_table2[mid] <= raw) 132 min = mid; 133 else if (rx51_temp_table2[mid] > raw) 134 max = mid; 135 if (rx51_temp_table2[mid] == raw) 136 break; 137 } 138 139 return (rx51_temp_table2_first - min) * 10; 140} 141 142/* 143 * Read ADCIN channel 4 (BSI) and convert RAW value to micro Ah 144 * This conversion formula was extracted from maemo program bsi-read 145 */ 146static int rx51_battery_read_capacity(struct rx51_device_info *di) 147{ 148 int capacity = rx51_battery_read_adc(di->channel_bsi); 149 150 if (capacity < 0) { 151 dev_err(di->dev, "Could not read ADC: %d\n", capacity); 152 return capacity; 153 } 154 155 return 1280 * (1200 * capacity)/(1024 - capacity); 156} 157 158/* 159 * Return power_supply property 160 */ 161static int rx51_battery_get_property(struct power_supply *psy, 162 enum power_supply_property psp, 163 union power_supply_propval *val) 164{ 165 struct rx51_device_info *di = power_supply_get_drvdata(psy); 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 power_supply_config psy_cfg = {}; 208 struct rx51_device_info *di; 209 int ret; 210 211 di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL); 212 if (!di) 213 return -ENOMEM; 214 215 platform_set_drvdata(pdev, di); 216 217 di->dev = &pdev->dev; 218 di->bat_desc.name = dev_name(&pdev->dev); 219 di->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY; 220 di->bat_desc.properties = rx51_battery_props; 221 di->bat_desc.num_properties = ARRAY_SIZE(rx51_battery_props); 222 di->bat_desc.get_property = rx51_battery_get_property; 223 224 psy_cfg.drv_data = di; 225 226 di->channel_temp = iio_channel_get(di->dev, "temp"); 227 if (IS_ERR(di->channel_temp)) { 228 ret = PTR_ERR(di->channel_temp); 229 goto error; 230 } 231 232 di->channel_bsi = iio_channel_get(di->dev, "bsi"); 233 if (IS_ERR(di->channel_bsi)) { 234 ret = PTR_ERR(di->channel_bsi); 235 goto error_channel_temp; 236 } 237 238 di->channel_vbat = iio_channel_get(di->dev, "vbat"); 239 if (IS_ERR(di->channel_vbat)) { 240 ret = PTR_ERR(di->channel_vbat); 241 goto error_channel_bsi; 242 } 243 244 di->bat = power_supply_register(di->dev, &di->bat_desc, &psy_cfg); 245 if (IS_ERR(di->bat)) { 246 ret = PTR_ERR(di->bat); 247 goto error_channel_vbat; 248 } 249 250 return 0; 251 252error_channel_vbat: 253 iio_channel_release(di->channel_vbat); 254error_channel_bsi: 255 iio_channel_release(di->channel_bsi); 256error_channel_temp: 257 iio_channel_release(di->channel_temp); 258error: 259 260 return ret; 261} 262 263static int rx51_battery_remove(struct platform_device *pdev) 264{ 265 struct rx51_device_info *di = platform_get_drvdata(pdev); 266 267 power_supply_unregister(di->bat); 268 269 iio_channel_release(di->channel_vbat); 270 iio_channel_release(di->channel_bsi); 271 iio_channel_release(di->channel_temp); 272 273 return 0; 274} 275 276#ifdef CONFIG_OF 277static const struct of_device_id n900_battery_of_match[] = { 278 {.compatible = "nokia,n900-battery", }, 279 { }, 280}; 281MODULE_DEVICE_TABLE(of, n900_battery_of_match); 282#endif 283 284static struct platform_driver rx51_battery_driver = { 285 .probe = rx51_battery_probe, 286 .remove = rx51_battery_remove, 287 .driver = { 288 .name = "rx51-battery", 289 .of_match_table = of_match_ptr(n900_battery_of_match), 290 }, 291}; 292module_platform_driver(rx51_battery_driver); 293 294MODULE_ALIAS("platform:rx51-battery"); 295MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>"); 296MODULE_DESCRIPTION("Nokia RX-51 battery driver"); 297MODULE_LICENSE("GPL"); 298