linux/drivers/power/wm831x_backup.c
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   1/*
   2 * Backup battery driver for Wolfson Microelectronics wm831x PMICs
   3 *
   4 * Copyright 2009 Wolfson Microelectronics PLC.
   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#include <linux/module.h>
  12#include <linux/err.h>
  13#include <linux/platform_device.h>
  14#include <linux/power_supply.h>
  15#include <linux/slab.h>
  16
  17#include <linux/mfd/wm831x/core.h>
  18#include <linux/mfd/wm831x/auxadc.h>
  19#include <linux/mfd/wm831x/pmu.h>
  20#include <linux/mfd/wm831x/pdata.h>
  21
  22struct wm831x_backup {
  23        struct wm831x *wm831x;
  24        struct power_supply backup;
  25        char name[20];
  26};
  27
  28static int wm831x_backup_read_voltage(struct wm831x *wm831x,
  29                                     enum wm831x_auxadc src,
  30                                     union power_supply_propval *val)
  31{
  32        int ret;
  33
  34        ret = wm831x_auxadc_read_uv(wm831x, src);
  35        if (ret >= 0)
  36                val->intval = ret;
  37
  38        return ret;
  39}
  40
  41/*********************************************************************
  42 *              Backup supply properties
  43 *********************************************************************/
  44
  45static void wm831x_config_backup(struct wm831x *wm831x)
  46{
  47        struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
  48        struct wm831x_backup_pdata *pdata;
  49        int ret, reg;
  50
  51        if (!wm831x_pdata || !wm831x_pdata->backup) {
  52                dev_warn(wm831x->dev,
  53                         "No backup battery charger configuration\n");
  54                return;
  55        }
  56
  57        pdata = wm831x_pdata->backup;
  58
  59        reg = 0;
  60
  61        if (pdata->charger_enable)
  62                reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
  63        if (pdata->no_constant_voltage)
  64                reg |= WM831X_BKUP_CHG_MODE;
  65
  66        switch (pdata->vlim) {
  67        case 2500:
  68                break;
  69        case 3100:
  70                reg |= WM831X_BKUP_CHG_VLIM;
  71                break;
  72        default:
  73                dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
  74                        pdata->vlim);
  75        }
  76
  77        switch (pdata->ilim) {
  78        case 100:
  79                break;
  80        case 200:
  81                reg |= 1;
  82                break;
  83        case 300:
  84                reg |= 2;
  85                break;
  86        case 400:
  87                reg |= 3;
  88                break;
  89        default:
  90                dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
  91                        pdata->ilim);
  92        }
  93
  94        ret = wm831x_reg_unlock(wm831x);
  95        if (ret != 0) {
  96                dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
  97                return;
  98        }
  99
 100        ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
 101                              WM831X_BKUP_CHG_ENA_MASK |
 102                              WM831X_BKUP_CHG_MODE_MASK |
 103                              WM831X_BKUP_BATT_DET_ENA_MASK |
 104                              WM831X_BKUP_CHG_VLIM_MASK |
 105                              WM831X_BKUP_CHG_ILIM_MASK,
 106                              reg);
 107        if (ret != 0)
 108                dev_err(wm831x->dev,
 109                        "Failed to set backup charger config: %d\n", ret);
 110
 111        wm831x_reg_lock(wm831x);
 112}
 113
 114static int wm831x_backup_get_prop(struct power_supply *psy,
 115                                  enum power_supply_property psp,
 116                                  union power_supply_propval *val)
 117{
 118        struct wm831x_backup *devdata = dev_get_drvdata(psy->dev->parent);
 119        struct wm831x *wm831x = devdata->wm831x;
 120        int ret = 0;
 121
 122        ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
 123        if (ret < 0)
 124                return ret;
 125
 126        switch (psp) {
 127        case POWER_SUPPLY_PROP_STATUS:
 128                if (ret & WM831X_BKUP_CHG_STS)
 129                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
 130                else
 131                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 132                break;
 133
 134        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 135                ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
 136                                                val);
 137                break;
 138
 139        case POWER_SUPPLY_PROP_PRESENT:
 140                if (ret & WM831X_BKUP_CHG_STS)
 141                        val->intval = 1;
 142                else
 143                        val->intval = 0;
 144                break;
 145
 146        default:
 147                ret = -EINVAL;
 148                break;
 149        }
 150
 151        return ret;
 152}
 153
 154static enum power_supply_property wm831x_backup_props[] = {
 155        POWER_SUPPLY_PROP_STATUS,
 156        POWER_SUPPLY_PROP_VOLTAGE_NOW,
 157        POWER_SUPPLY_PROP_PRESENT,
 158};
 159
 160/*********************************************************************
 161 *              Initialisation
 162 *********************************************************************/
 163
 164static __devinit int wm831x_backup_probe(struct platform_device *pdev)
 165{
 166        struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 167        struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
 168        struct wm831x_backup *devdata;
 169        struct power_supply *backup;
 170        int ret;
 171
 172        devdata = kzalloc(sizeof(struct wm831x_backup), GFP_KERNEL);
 173        if (devdata == NULL)
 174                return -ENOMEM;
 175
 176        devdata->wm831x = wm831x;
 177        platform_set_drvdata(pdev, devdata);
 178
 179        backup = &devdata->backup;
 180
 181        /* We ignore configuration failures since we can still read
 182         * back the status without enabling the charger (which may
 183         * already be enabled anyway).
 184         */
 185        wm831x_config_backup(wm831x);
 186
 187        if (wm831x_pdata && wm831x_pdata->wm831x_num)
 188                snprintf(devdata->name, sizeof(devdata->name),
 189                         "wm831x-backup.%d", wm831x_pdata->wm831x_num);
 190        else
 191                snprintf(devdata->name, sizeof(devdata->name),
 192                         "wm831x-backup");
 193
 194        backup->name = devdata->name;
 195        backup->type = POWER_SUPPLY_TYPE_BATTERY;
 196        backup->properties = wm831x_backup_props;
 197        backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
 198        backup->get_property = wm831x_backup_get_prop;
 199        ret = power_supply_register(&pdev->dev, backup);
 200        if (ret)
 201                goto err_kmalloc;
 202
 203        return ret;
 204
 205err_kmalloc:
 206        kfree(devdata);
 207        return ret;
 208}
 209
 210static __devexit int wm831x_backup_remove(struct platform_device *pdev)
 211{
 212        struct wm831x_backup *devdata = platform_get_drvdata(pdev);
 213
 214        power_supply_unregister(&devdata->backup);
 215        kfree(devdata->backup.name);
 216        kfree(devdata);
 217
 218        return 0;
 219}
 220
 221static struct platform_driver wm831x_backup_driver = {
 222        .probe = wm831x_backup_probe,
 223        .remove = __devexit_p(wm831x_backup_remove),
 224        .driver = {
 225                .name = "wm831x-backup",
 226        },
 227};
 228
 229module_platform_driver(wm831x_backup_driver);
 230
 231MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
 232MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 233MODULE_LICENSE("GPL");
 234MODULE_ALIAS("platform:wm831x-backup");
 235
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