linux/drivers/power/z2_battery.c
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   1/*
   2 * Battery measurement code for Zipit Z2
   3 *
   4 * Copyright (C) 2009 Peter Edwards <sweetlilmre@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 version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/gpio.h>
  14#include <linux/i2c.h>
  15#include <linux/interrupt.h>
  16#include <linux/irq.h>
  17#include <linux/power_supply.h>
  18#include <linux/slab.h>
  19#include <linux/z2_battery.h>
  20
  21#define Z2_DEFAULT_NAME "Z2"
  22
  23struct z2_charger {
  24        struct z2_battery_info          *info;
  25        int                             bat_status;
  26        struct i2c_client               *client;
  27        struct power_supply             *batt_ps;
  28        struct power_supply_desc        batt_ps_desc;
  29        struct mutex                    work_lock;
  30        struct work_struct              bat_work;
  31};
  32
  33static unsigned long z2_read_bat(struct z2_charger *charger)
  34{
  35        int data;
  36        data = i2c_smbus_read_byte_data(charger->client,
  37                                        charger->info->batt_I2C_reg);
  38        if (data < 0)
  39                return 0;
  40
  41        return data * charger->info->batt_mult / charger->info->batt_div;
  42}
  43
  44static int z2_batt_get_property(struct power_supply *batt_ps,
  45                            enum power_supply_property psp,
  46                            union power_supply_propval *val)
  47{
  48        struct z2_charger *charger = power_supply_get_drvdata(batt_ps);
  49        struct z2_battery_info *info = charger->info;
  50
  51        switch (psp) {
  52        case POWER_SUPPLY_PROP_STATUS:
  53                val->intval = charger->bat_status;
  54                break;
  55        case POWER_SUPPLY_PROP_TECHNOLOGY:
  56                val->intval = info->batt_tech;
  57                break;
  58        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  59                if (info->batt_I2C_reg >= 0)
  60                        val->intval = z2_read_bat(charger);
  61                else
  62                        return -EINVAL;
  63                break;
  64        case POWER_SUPPLY_PROP_VOLTAGE_MAX:
  65                if (info->max_voltage >= 0)
  66                        val->intval = info->max_voltage;
  67                else
  68                        return -EINVAL;
  69                break;
  70        case POWER_SUPPLY_PROP_VOLTAGE_MIN:
  71                if (info->min_voltage >= 0)
  72                        val->intval = info->min_voltage;
  73                else
  74                        return -EINVAL;
  75                break;
  76        case POWER_SUPPLY_PROP_PRESENT:
  77                val->intval = 1;
  78                break;
  79        default:
  80                return -EINVAL;
  81        }
  82
  83        return 0;
  84}
  85
  86static void z2_batt_ext_power_changed(struct power_supply *batt_ps)
  87{
  88        struct z2_charger *charger = power_supply_get_drvdata(batt_ps);
  89
  90        schedule_work(&charger->bat_work);
  91}
  92
  93static void z2_batt_update(struct z2_charger *charger)
  94{
  95        int old_status = charger->bat_status;
  96        struct z2_battery_info *info;
  97
  98        info = charger->info;
  99
 100        mutex_lock(&charger->work_lock);
 101
 102        charger->bat_status = (info->charge_gpio >= 0) ?
 103                (gpio_get_value(info->charge_gpio) ?
 104                POWER_SUPPLY_STATUS_CHARGING :
 105                POWER_SUPPLY_STATUS_DISCHARGING) :
 106                POWER_SUPPLY_STATUS_UNKNOWN;
 107
 108        if (old_status != charger->bat_status) {
 109                pr_debug("%s: %i -> %i\n", charger->batt_ps->desc->name,
 110                                old_status,
 111                                charger->bat_status);
 112                power_supply_changed(charger->batt_ps);
 113        }
 114
 115        mutex_unlock(&charger->work_lock);
 116}
 117
 118static void z2_batt_work(struct work_struct *work)
 119{
 120        struct z2_charger *charger;
 121        charger = container_of(work, struct z2_charger, bat_work);
 122        z2_batt_update(charger);
 123}
 124
 125static irqreturn_t z2_charge_switch_irq(int irq, void *devid)
 126{
 127        struct z2_charger *charger = devid;
 128        schedule_work(&charger->bat_work);
 129        return IRQ_HANDLED;
 130}
 131
 132static int z2_batt_ps_init(struct z2_charger *charger, int props)
 133{
 134        int i = 0;
 135        enum power_supply_property *prop;
 136        struct z2_battery_info *info = charger->info;
 137
 138        if (info->charge_gpio >= 0)
 139                props++;        /* POWER_SUPPLY_PROP_STATUS */
 140        if (info->batt_tech >= 0)
 141                props++;        /* POWER_SUPPLY_PROP_TECHNOLOGY */
 142        if (info->batt_I2C_reg >= 0)
 143                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_NOW */
 144        if (info->max_voltage >= 0)
 145                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_MAX */
 146        if (info->min_voltage >= 0)
 147                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_MIN */
 148
 149        prop = kzalloc(props * sizeof(*prop), GFP_KERNEL);
 150        if (!prop)
 151                return -ENOMEM;
 152
 153        prop[i++] = POWER_SUPPLY_PROP_PRESENT;
 154        if (info->charge_gpio >= 0)
 155                prop[i++] = POWER_SUPPLY_PROP_STATUS;
 156        if (info->batt_tech >= 0)
 157                prop[i++] = POWER_SUPPLY_PROP_TECHNOLOGY;
 158        if (info->batt_I2C_reg >= 0)
 159                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_NOW;
 160        if (info->max_voltage >= 0)
 161                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MAX;
 162        if (info->min_voltage >= 0)
 163                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MIN;
 164
 165        if (!info->batt_name) {
 166                dev_info(&charger->client->dev,
 167                                "Please consider setting proper battery "
 168                                "name in platform definition file, falling "
 169                                "back to name \" Z2_DEFAULT_NAME \"\n");
 170                charger->batt_ps_desc.name = Z2_DEFAULT_NAME;
 171        } else
 172                charger->batt_ps_desc.name = info->batt_name;
 173
 174        charger->batt_ps_desc.properties        = prop;
 175        charger->batt_ps_desc.num_properties    = props;
 176        charger->batt_ps_desc.type              = POWER_SUPPLY_TYPE_BATTERY;
 177        charger->batt_ps_desc.get_property      = z2_batt_get_property;
 178        charger->batt_ps_desc.external_power_changed =
 179                                                z2_batt_ext_power_changed;
 180        charger->batt_ps_desc.use_for_apm       = 1;
 181
 182        return 0;
 183}
 184
 185static int z2_batt_probe(struct i2c_client *client,
 186                                const struct i2c_device_id *id)
 187{
 188        int ret = 0;
 189        int props = 1;  /* POWER_SUPPLY_PROP_PRESENT */
 190        struct z2_charger *charger;
 191        struct z2_battery_info *info = client->dev.platform_data;
 192        struct power_supply_config psy_cfg = {};
 193
 194        if (info == NULL) {
 195                dev_err(&client->dev,
 196                        "Please set platform device platform_data"
 197                        " to a valid z2_battery_info pointer!\n");
 198                return -EINVAL;
 199        }
 200
 201        charger = kzalloc(sizeof(*charger), GFP_KERNEL);
 202        if (charger == NULL)
 203                return -ENOMEM;
 204
 205        charger->bat_status = POWER_SUPPLY_STATUS_UNKNOWN;
 206        charger->info = info;
 207        charger->client = client;
 208        i2c_set_clientdata(client, charger);
 209        psy_cfg.drv_data = charger;
 210
 211        mutex_init(&charger->work_lock);
 212
 213        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
 214                ret = gpio_request(info->charge_gpio, "BATT CHRG");
 215                if (ret)
 216                        goto err;
 217
 218                ret = gpio_direction_input(info->charge_gpio);
 219                if (ret)
 220                        goto err2;
 221
 222                irq_set_irq_type(gpio_to_irq(info->charge_gpio),
 223                                 IRQ_TYPE_EDGE_BOTH);
 224                ret = request_irq(gpio_to_irq(info->charge_gpio),
 225                                z2_charge_switch_irq, 0,
 226                                "AC Detect", charger);
 227                if (ret)
 228                        goto err3;
 229        }
 230
 231        ret = z2_batt_ps_init(charger, props);
 232        if (ret)
 233                goto err3;
 234
 235        INIT_WORK(&charger->bat_work, z2_batt_work);
 236
 237        charger->batt_ps = power_supply_register(&client->dev,
 238                                                 &charger->batt_ps_desc,
 239                                                 &psy_cfg);
 240        if (IS_ERR(charger->batt_ps)) {
 241                ret = PTR_ERR(charger->batt_ps);
 242                goto err4;
 243        }
 244
 245        schedule_work(&charger->bat_work);
 246
 247        return 0;
 248
 249err4:
 250        kfree(charger->batt_ps_desc.properties);
 251err3:
 252        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
 253                free_irq(gpio_to_irq(info->charge_gpio), charger);
 254err2:
 255        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
 256                gpio_free(info->charge_gpio);
 257err:
 258        kfree(charger);
 259        return ret;
 260}
 261
 262static int z2_batt_remove(struct i2c_client *client)
 263{
 264        struct z2_charger *charger = i2c_get_clientdata(client);
 265        struct z2_battery_info *info = charger->info;
 266
 267        cancel_work_sync(&charger->bat_work);
 268        power_supply_unregister(charger->batt_ps);
 269
 270        kfree(charger->batt_ps_desc.properties);
 271        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
 272                free_irq(gpio_to_irq(info->charge_gpio), charger);
 273                gpio_free(info->charge_gpio);
 274        }
 275
 276        kfree(charger);
 277
 278        return 0;
 279}
 280
 281#ifdef CONFIG_PM
 282static int z2_batt_suspend(struct device *dev)
 283{
 284        struct i2c_client *client = to_i2c_client(dev);
 285        struct z2_charger *charger = i2c_get_clientdata(client);
 286
 287        flush_work(&charger->bat_work);
 288        return 0;
 289}
 290
 291static int z2_batt_resume(struct device *dev)
 292{
 293        struct i2c_client *client = to_i2c_client(dev);
 294        struct z2_charger *charger = i2c_get_clientdata(client);
 295
 296        schedule_work(&charger->bat_work);
 297        return 0;
 298}
 299
 300static const struct dev_pm_ops z2_battery_pm_ops = {
 301        .suspend        = z2_batt_suspend,
 302        .resume         = z2_batt_resume,
 303};
 304
 305#define Z2_BATTERY_PM_OPS       (&z2_battery_pm_ops)
 306
 307#else
 308#define Z2_BATTERY_PM_OPS       (NULL)
 309#endif
 310
 311static const struct i2c_device_id z2_batt_id[] = {
 312        { "aer915", 0 },
 313        { }
 314};
 315MODULE_DEVICE_TABLE(i2c, z2_batt_id);
 316
 317static struct i2c_driver z2_batt_driver = {
 318        .driver = {
 319                .name   = "z2-battery",
 320                .owner  = THIS_MODULE,
 321                .pm     = Z2_BATTERY_PM_OPS
 322        },
 323        .probe          = z2_batt_probe,
 324        .remove         = z2_batt_remove,
 325        .id_table       = z2_batt_id,
 326};
 327module_i2c_driver(z2_batt_driver);
 328
 329MODULE_LICENSE("GPL");
 330MODULE_AUTHOR("Peter Edwards <sweetlilmre@gmail.com>");
 331MODULE_DESCRIPTION("Zipit Z2 battery driver");
 332