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Linux/drivers/power/rx51_battery.c

  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 
 30 struct 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  */
 42 static 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  */
 55 static 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  */
 81 static 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
 93 static 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  */
107 static 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  */
146 static 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  */
161 static 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 
196 static 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 
205 static 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 
252 error_channel_vbat:
253         iio_channel_release(di->channel_vbat);
254 error_channel_bsi:
255         iio_channel_release(di->channel_bsi);
256 error_channel_temp:
257         iio_channel_release(di->channel_temp);
258 error:
259 
260         return ret;
261 }
262 
263 static 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
277 static const struct of_device_id n900_battery_of_match[] = {
278         {.compatible = "nokia,n900-battery", },
279         { },
280 };
281 MODULE_DEVICE_TABLE(of, n900_battery_of_match);
282 #endif
283 
284 static 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 };
292 module_platform_driver(rx51_battery_driver);
293 
294 MODULE_ALIAS("platform:rx51-battery");
295 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
296 MODULE_DESCRIPTION("Nokia RX-51 battery driver");
297 MODULE_LICENSE("GPL");
298 

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