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 mutex            work_lock;
  29        struct work_struct      bat_work;
  30};
  31
  32static unsigned long z2_read_bat(struct z2_charger *charger)
  33{
  34        int data;
  35        data = i2c_smbus_read_byte_data(charger->client,
  36                                        charger->info->batt_I2C_reg);
  37        if (data < 0)
  38                return 0;
  39
  40        return data * charger->info->batt_mult / charger->info->batt_div;
  41}
  42
  43static int z2_batt_get_property(struct power_supply *batt_ps,
  44                            enum power_supply_property psp,
  45                            union power_supply_propval *val)
  46{
  47        struct z2_charger *charger = container_of(batt_ps, struct z2_charger,
  48                                                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 = container_of(batt_ps, struct z2_charger,
  89                                                batt_ps);
  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.name, old_status,
 110                        charger->bat_status);
 111                power_supply_changed(&charger->batt_ps);
 112        }
 113
 114        mutex_unlock(&charger->work_lock);
 115}
 116
 117static void z2_batt_work(struct work_struct *work)
 118{
 119        struct z2_charger *charger;
 120        charger = container_of(work, struct z2_charger, bat_work);
 121        z2_batt_update(charger);
 122}
 123
 124static irqreturn_t z2_charge_switch_irq(int irq, void *devid)
 125{
 126        struct z2_charger *charger = devid;
 127        schedule_work(&charger->bat_work);
 128        return IRQ_HANDLED;
 129}
 130
 131static int z2_batt_ps_init(struct z2_charger *charger, int props)
 132{
 133        int i = 0;
 134        enum power_supply_property *prop;
 135        struct z2_battery_info *info = charger->info;
 136
 137        if (info->batt_tech >= 0)
 138                props++;        /* POWER_SUPPLY_PROP_TECHNOLOGY */
 139        if (info->batt_I2C_reg >= 0)
 140                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_NOW */
 141        if (info->max_voltage >= 0)
 142                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_MAX */
 143        if (info->min_voltage >= 0)
 144                props++;        /* POWER_SUPPLY_PROP_VOLTAGE_MIN */
 145
 146        prop = kzalloc(props * sizeof(*prop), GFP_KERNEL);
 147        if (!prop)
 148                return -ENOMEM;
 149
 150        prop[i++] = POWER_SUPPLY_PROP_PRESENT;
 151        if (info->charge_gpio >= 0)
 152                prop[i++] = POWER_SUPPLY_PROP_STATUS;
 153        if (info->batt_tech >= 0)
 154                prop[i++] = POWER_SUPPLY_PROP_TECHNOLOGY;
 155        if (info->batt_I2C_reg >= 0)
 156                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_NOW;
 157        if (info->max_voltage >= 0)
 158                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MAX;
 159        if (info->min_voltage >= 0)
 160                prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MIN;
 161
 162        if (!info->batt_name) {
 163                dev_info(&charger->client->dev,
 164                                "Please consider setting proper battery "
 165                                "name in platform definition file, falling "
 166                                "back to name \" Z2_DEFAULT_NAME \"\n");
 167                charger->batt_ps.name = Z2_DEFAULT_NAME;
 168        } else
 169                charger->batt_ps.name = info->batt_name;
 170
 171        charger->batt_ps.properties             = prop;
 172        charger->batt_ps.num_properties         = props;
 173        charger->batt_ps.type                   = POWER_SUPPLY_TYPE_BATTERY;
 174        charger->batt_ps.get_property           = z2_batt_get_property;
 175        charger->batt_ps.external_power_changed = z2_batt_ext_power_changed;
 176        charger->batt_ps.use_for_apm            = 1;
 177
 178        return 0;
 179}
 180
 181static int __devinit z2_batt_probe(struct i2c_client *client,
 182                                const struct i2c_device_id *id)
 183{
 184        int ret = 0;
 185        int props = 1;  /* POWER_SUPPLY_PROP_PRESENT */
 186        struct z2_charger *charger;
 187        struct z2_battery_info *info = client->dev.platform_data;
 188
 189        if (info == NULL) {
 190                dev_err(&client->dev,
 191                        "Please set platform device platform_data"
 192                        " to a valid z2_battery_info pointer!\n");
 193                return -EINVAL;
 194        }
 195
 196        charger = kzalloc(sizeof(*charger), GFP_KERNEL);
 197        if (charger == NULL)
 198                return -ENOMEM;
 199
 200        charger->bat_status = POWER_SUPPLY_STATUS_UNKNOWN;
 201        charger->info = info;
 202        charger->client = client;
 203        i2c_set_clientdata(client, charger);
 204
 205        mutex_init(&charger->work_lock);
 206
 207        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
 208                ret = gpio_request(info->charge_gpio, "BATT CHRG");
 209                if (ret)
 210                        goto err;
 211
 212                ret = gpio_direction_input(info->charge_gpio);
 213                if (ret)
 214                        goto err2;
 215
 216                set_irq_type(gpio_to_irq(info->charge_gpio),
 217                                IRQ_TYPE_EDGE_BOTH);
 218                ret = request_irq(gpio_to_irq(info->charge_gpio),
 219                                z2_charge_switch_irq, IRQF_DISABLED,
 220                                "AC Detect", charger);
 221                if (ret)
 222                        goto err3;
 223        }
 224
 225        ret = z2_batt_ps_init(charger, props);
 226        if (ret)
 227                goto err3;
 228
 229        INIT_WORK(&charger->bat_work, z2_batt_work);
 230
 231        ret = power_supply_register(&client->dev, &charger->batt_ps);
 232        if (ret)
 233                goto err4;
 234
 235        schedule_work(&charger->bat_work);
 236
 237        return 0;
 238
 239err4:
 240        kfree(charger->batt_ps.properties);
 241err3:
 242        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
 243                free_irq(gpio_to_irq(info->charge_gpio), charger);
 244err2:
 245        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
 246                gpio_free(info->charge_gpio);
 247err:
 248        kfree(charger);
 249        return ret;
 250}
 251
 252static int __devexit z2_batt_remove(struct i2c_client *client)
 253{
 254        struct z2_charger *charger = i2c_get_clientdata(client);
 255        struct z2_battery_info *info = charger->info;
 256
 257        flush_scheduled_work();
 258        power_supply_unregister(&charger->batt_ps);
 259
 260        kfree(charger->batt_ps.properties);
 261        if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
 262                free_irq(gpio_to_irq(info->charge_gpio), charger);
 263                gpio_free(info->charge_gpio);
 264        }
 265
 266        kfree(charger);
 267
 268        return 0;
 269}
 270
 271#ifdef CONFIG_PM
 272static int z2_batt_suspend(struct i2c_client *client, pm_message_t state)
 273{
 274        flush_scheduled_work();
 275        return 0;
 276}
 277
 278static int z2_batt_resume(struct i2c_client *client)
 279{
 280        struct z2_charger *charger = i2c_get_clientdata(client);
 281
 282        schedule_work(&charger->bat_work);
 283        return 0;
 284}
 285#else
 286#define z2_batt_suspend NULL
 287#define z2_batt_resume NULL
 288#endif
 289
 290static const struct i2c_device_id z2_batt_id[] = {
 291        { "aer915", 0 },
 292        { }
 293};
 294
 295static struct i2c_driver z2_batt_driver = {
 296        .driver = {
 297                .name   = "z2-battery",
 298                .owner  = THIS_MODULE,
 299        },
 300        .probe          = z2_batt_probe,
 301        .remove         = z2_batt_remove,
 302        .suspend        = z2_batt_suspend,
 303        .resume         = z2_batt_resume,
 304        .id_table       = z2_batt_id,
 305};
 306
 307static int __init z2_batt_init(void)
 308{
 309        return i2c_add_driver(&z2_batt_driver);
 310}
 311
 312static void __exit z2_batt_exit(void)
 313{
 314        i2c_del_driver(&z2_batt_driver);
 315}
 316
 317module_init(z2_batt_init);
 318module_exit(z2_batt_exit);
 319
 320MODULE_LICENSE("GPL");
 321MODULE_AUTHOR("Peter Edwards <sweetlilmre@gmail.com>");
 322MODULE_DESCRIPTION("Zipit Z2 battery driver");
 323
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