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Linux/drivers/power/twl4030_madc_battery.c

  1 /*
  2  * Dumb driver for LiIon batteries using TWL4030 madc.
  3  *
  4  * Copyright 2013 Golden Delicious Computers
  5  * Lukas Märdian <lukas@goldelico.com>
  6  *
  7  * Based on dumb driver for gta01 battery
  8  * Copyright 2009 Openmoko, Inc
  9  * Balaji Rao <balajirrao@openmoko.org>
 10  */
 11 
 12 #include <linux/module.h>
 13 #include <linux/param.h>
 14 #include <linux/delay.h>
 15 #include <linux/workqueue.h>
 16 #include <linux/platform_device.h>
 17 #include <linux/power_supply.h>
 18 #include <linux/slab.h>
 19 #include <linux/sort.h>
 20 #include <linux/i2c/twl4030-madc.h>
 21 #include <linux/power/twl4030_madc_battery.h>
 22 
 23 struct twl4030_madc_battery {
 24         struct power_supply psy;
 25         struct twl4030_madc_bat_platform_data *pdata;
 26 };
 27 
 28 static enum power_supply_property twl4030_madc_bat_props[] = {
 29         POWER_SUPPLY_PROP_PRESENT,
 30         POWER_SUPPLY_PROP_STATUS,
 31         POWER_SUPPLY_PROP_TECHNOLOGY,
 32         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 33         POWER_SUPPLY_PROP_CURRENT_NOW,
 34         POWER_SUPPLY_PROP_CAPACITY,
 35         POWER_SUPPLY_PROP_CHARGE_FULL,
 36         POWER_SUPPLY_PROP_CHARGE_NOW,
 37         POWER_SUPPLY_PROP_TEMP,
 38         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 39 };
 40 
 41 static int madc_read(int index)
 42 {
 43         struct twl4030_madc_request req;
 44         int val;
 45 
 46         req.channels = index;
 47         req.method = TWL4030_MADC_SW2;
 48         req.type = TWL4030_MADC_WAIT;
 49         req.do_avg = 0;
 50         req.raw = false;
 51         req.func_cb = NULL;
 52 
 53         val = twl4030_madc_conversion(&req);
 54         if (val < 0)
 55                 return val;
 56 
 57         return req.rbuf[ffs(index) - 1];
 58 }
 59 
 60 static int twl4030_madc_bat_get_charging_status(void)
 61 {
 62         return (madc_read(TWL4030_MADC_ICHG) > 0) ? 1 : 0;
 63 }
 64 
 65 static int twl4030_madc_bat_get_voltage(void)
 66 {
 67         return madc_read(TWL4030_MADC_VBAT);
 68 }
 69 
 70 static int twl4030_madc_bat_get_current(void)
 71 {
 72         return madc_read(TWL4030_MADC_ICHG) * 1000;
 73 }
 74 
 75 static int twl4030_madc_bat_get_temp(void)
 76 {
 77         return madc_read(TWL4030_MADC_BTEMP) * 10;
 78 }
 79 
 80 static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
 81                                         int volt)
 82 {
 83         struct twl4030_madc_bat_calibration *calibration;
 84         int i, res = 0;
 85 
 86         /* choose charging curve */
 87         if (twl4030_madc_bat_get_charging_status())
 88                 calibration = bat->pdata->charging;
 89         else
 90                 calibration = bat->pdata->discharging;
 91 
 92         if (volt > calibration[0].voltage) {
 93                 res = calibration[0].level;
 94         } else {
 95                 for (i = 0; calibration[i+1].voltage >= 0; i++) {
 96                         if (volt <= calibration[i].voltage &&
 97                                         volt >= calibration[i+1].voltage) {
 98                                 /* interval found - interpolate within range */
 99                                 res = calibration[i].level -
100                                         ((calibration[i].voltage - volt) *
101                                         (calibration[i].level -
102                                         calibration[i+1].level)) /
103                                         (calibration[i].voltage -
104                                         calibration[i+1].voltage);
105                                 break;
106                         }
107                 }
108         }
109         return res;
110 }
111 
112 static int twl4030_madc_bat_get_property(struct power_supply *psy,
113                                         enum power_supply_property psp,
114                                         union power_supply_propval *val)
115 {
116         struct twl4030_madc_battery *bat = container_of(psy,
117                                         struct twl4030_madc_battery, psy);
118 
119         switch (psp) {
120         case POWER_SUPPLY_PROP_STATUS:
121                 if (twl4030_madc_bat_voltscale(bat,
122                                 twl4030_madc_bat_get_voltage()) > 95)
123                         val->intval = POWER_SUPPLY_STATUS_FULL;
124                 else {
125                         if (twl4030_madc_bat_get_charging_status())
126                                 val->intval = POWER_SUPPLY_STATUS_CHARGING;
127                         else
128                                 val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
129                 }
130                 break;
131         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
132                 val->intval = twl4030_madc_bat_get_voltage() * 1000;
133                 break;
134         case POWER_SUPPLY_PROP_TECHNOLOGY:
135                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
136                 break;
137         case POWER_SUPPLY_PROP_CURRENT_NOW:
138                 val->intval = twl4030_madc_bat_get_current();
139                 break;
140         case POWER_SUPPLY_PROP_PRESENT:
141                 /* assume battery is always present */
142                 val->intval = 1;
143                 break;
144         case POWER_SUPPLY_PROP_CHARGE_NOW: {
145                         int percent = twl4030_madc_bat_voltscale(bat,
146                                         twl4030_madc_bat_get_voltage());
147                         val->intval = (percent * bat->pdata->capacity) / 100;
148                         break;
149                 }
150         case POWER_SUPPLY_PROP_CAPACITY:
151                 val->intval = twl4030_madc_bat_voltscale(bat,
152                                         twl4030_madc_bat_get_voltage());
153                 break;
154         case POWER_SUPPLY_PROP_CHARGE_FULL:
155                 val->intval = bat->pdata->capacity;
156                 break;
157         case POWER_SUPPLY_PROP_TEMP:
158                 val->intval = twl4030_madc_bat_get_temp();
159                 break;
160         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
161                         int percent = twl4030_madc_bat_voltscale(bat,
162                                         twl4030_madc_bat_get_voltage());
163                         /* in mAh */
164                         int chg = (percent * (bat->pdata->capacity/1000))/100;
165 
166                         /* assume discharge with 400 mA (ca. 1.5W) */
167                         val->intval = (3600l * chg) / 400;
168                         break;
169                 }
170         default:
171                 return -EINVAL;
172         }
173 
174         return 0;
175 }
176 
177 static void twl4030_madc_bat_ext_changed(struct power_supply *psy)
178 {
179         struct twl4030_madc_battery *bat = container_of(psy,
180                                         struct twl4030_madc_battery, psy);
181 
182         power_supply_changed(&bat->psy);
183 }
184 
185 static int twl4030_cmp(const void *a, const void *b)
186 {
187         return ((struct twl4030_madc_bat_calibration *)b)->voltage -
188                 ((struct twl4030_madc_bat_calibration *)a)->voltage;
189 }
190 
191 static int twl4030_madc_battery_probe(struct platform_device *pdev)
192 {
193         struct twl4030_madc_battery *twl4030_madc_bat;
194         struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
195 
196         twl4030_madc_bat = kzalloc(sizeof(*twl4030_madc_bat), GFP_KERNEL);
197         if (!twl4030_madc_bat)
198                 return -ENOMEM;
199 
200         twl4030_madc_bat->psy.name = "twl4030_battery";
201         twl4030_madc_bat->psy.type = POWER_SUPPLY_TYPE_BATTERY;
202         twl4030_madc_bat->psy.properties = twl4030_madc_bat_props;
203         twl4030_madc_bat->psy.num_properties =
204                                         ARRAY_SIZE(twl4030_madc_bat_props);
205         twl4030_madc_bat->psy.get_property = twl4030_madc_bat_get_property;
206         twl4030_madc_bat->psy.external_power_changed =
207                                         twl4030_madc_bat_ext_changed;
208 
209         /* sort charging and discharging calibration data */
210         sort(pdata->charging, pdata->charging_size,
211                 sizeof(struct twl4030_madc_bat_calibration),
212                 twl4030_cmp, NULL);
213         sort(pdata->discharging, pdata->discharging_size,
214                 sizeof(struct twl4030_madc_bat_calibration),
215                 twl4030_cmp, NULL);
216 
217         twl4030_madc_bat->pdata = pdata;
218         platform_set_drvdata(pdev, twl4030_madc_bat);
219         power_supply_register(&pdev->dev, &twl4030_madc_bat->psy);
220 
221         return 0;
222 }
223 
224 static int twl4030_madc_battery_remove(struct platform_device *pdev)
225 {
226         struct twl4030_madc_battery *bat = platform_get_drvdata(pdev);
227 
228         power_supply_unregister(&bat->psy);
229         kfree(bat);
230 
231         return 0;
232 }
233 
234 static struct platform_driver twl4030_madc_battery_driver = {
235         .driver = {
236                 .name = "twl4030_madc_battery",
237         },
238         .probe  = twl4030_madc_battery_probe,
239         .remove = twl4030_madc_battery_remove,
240 };
241 module_platform_driver(twl4030_madc_battery_driver);
242 
243 MODULE_LICENSE("GPL");
244 MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
245 MODULE_DESCRIPTION("twl4030_madc battery driver");
246 

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