drivers/power/wm831x_backup.c

   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
  22 struct wm831x_backup {
  23         struct wm831x *wm831x;
  24         struct power_supply backup;
  25 };
  26
  27 static int wm831x_backup_read_voltage(struct wm831x *wm831x,
  28                                      enum wm831x_auxadc src,
  29                                      union power_supply_propval *val)
  30 {
  31         int ret;
  32
  33         ret = wm831x_auxadc_read_uv(wm831x, src);
  34         if (ret >= 0)
  35                 val->intval = ret;
  36
  37         return ret;
  38 }
  39
  40 /*********************************************************************
  41  *              Backup supply properties
  42  *********************************************************************/
  43
  44 static void wm831x_config_backup(struct wm831x *wm831x)
  45 {
  46         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
  47         struct wm831x_backup_pdata *pdata;
  48         int ret, reg;
  49
  50         if (!wm831x_pdata || !wm831x_pdata->backup) {
  51                 dev_warn(wm831x->dev,
  52                          "No backup battery charger configuration\n");
  53                 return;
  54         }
  55
  56         pdata = wm831x_pdata->backup;
  57
  58         reg = 0;
  59
  60         if (pdata->charger_enable)
  61                 reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
  62         if (pdata->no_constant_voltage)
  63                 reg |= WM831X_BKUP_CHG_MODE;
  64
  65         switch (pdata->vlim) {
  66         case 2500:
  67                 break;
  68         case 3100:
  69                 reg |= WM831X_BKUP_CHG_VLIM;
  70                 break;
  71         default:
  72                 dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
  73                         pdata->vlim);
  74         }
  75
  76         switch (pdata->ilim) {
  77         case 100:
  78                 break;
  79         case 200:
  80                 reg |= 1;
  81                 break;
  82         case 300:
  83                 reg |= 2;
  84                 break;
  85         case 400:
  86                 reg |= 3;
  87                 break;
  88         default:
  89                 dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
  90                         pdata->ilim);
  91         }
  92
  93         ret = wm831x_reg_unlock(wm831x);
  94         if (ret != 0) {
  95                 dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
  96                 return;
  97         }
  98
  99         ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
 100                               WM831X_BKUP_CHG_ENA_MASK |
 101                               WM831X_BKUP_CHG_MODE_MASK |
 102                               WM831X_BKUP_BATT_DET_ENA_MASK |
 103                               WM831X_BKUP_CHG_VLIM_MASK |
 104                               WM831X_BKUP_CHG_ILIM_MASK,
 105                               reg);
 106         if (ret != 0)
 107                 dev_err(wm831x->dev,
 108                         "Failed to set backup charger config: %d\n", ret);
 109
 110         wm831x_reg_lock(wm831x);
 111 }
 112
 113 static int wm831x_backup_get_prop(struct power_supply *psy,
 114                                   enum power_supply_property psp,
 115                                   union power_supply_propval *val)
 116 {
 117         struct wm831x_backup *devdata = dev_get_drvdata(psy->dev->parent);
 118         struct wm831x *wm831x = devdata->wm831x;
 119         int ret = 0;
 120
 121         ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
 122         if (ret < 0)
 123                 return ret;
 124
 125         switch (psp) {
 126         case POWER_SUPPLY_PROP_STATUS:
 127                 if (ret & WM831X_BKUP_CHG_STS)
 128                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
 129                 else
 130                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 131                 break;
 132
 133         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 134                 ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
 135                                                 val);
 136                 break;
 137
 138         case POWER_SUPPLY_PROP_PRESENT:
 139                 if (ret & WM831X_BKUP_CHG_STS)
 140                         val->intval = 1;
 141                 else
 142                         val->intval = 0;
 143                 break;
 144
 145         default:
 146                 ret = -EINVAL;
 147                 break;
 148         }
 149
 150         return ret;
 151 }
 152
 153 static enum power_supply_property wm831x_backup_props[] = {
 154         POWER_SUPPLY_PROP_STATUS,
 155         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 156         POWER_SUPPLY_PROP_PRESENT,
 157 };
 158
 159 /*********************************************************************
 160  *              Initialisation
 161  *********************************************************************/
 162
 163 static __devinit int wm831x_backup_probe(struct platform_device *pdev)
 164 {
 165         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 166         struct wm831x_backup *devdata;
 167         struct power_supply *backup;
 168         int ret;
 169
 170         devdata = kzalloc(sizeof(struct wm831x_backup), GFP_KERNEL);
 171         if (devdata == NULL)
 172                 return -ENOMEM;
 173
 174         devdata->wm831x = wm831x;
 175         platform_set_drvdata(pdev, devdata);
 176
 177         backup = &devdata->backup;
 178
 179         /* We ignore configuration failures since we can still read
 180          * back the status without enabling the charger (which may
 181          * already be enabled anyway).
 182          */
 183         wm831x_config_backup(wm831x);
 184
 185         backup->name = "wm831x-backup";
 186         backup->type = POWER_SUPPLY_TYPE_BATTERY;
 187         backup->properties = wm831x_backup_props;
 188         backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
 189         backup->get_property = wm831x_backup_get_prop;
 190         ret = power_supply_register(&pdev->dev, backup);
 191         if (ret)
 192                 goto err_kmalloc;
 193
 194         return ret;
 195
 196 err_kmalloc:
 197         kfree(devdata);
 198         return ret;
 199 }
 200
 201 static __devexit int wm831x_backup_remove(struct platform_device *pdev)
 202 {
 203         struct wm831x_backup *devdata = platform_get_drvdata(pdev);
 204
 205         power_supply_unregister(&devdata->backup);
 206         kfree(devdata);
 207
 208         return 0;
 209 }
 210
 211 static struct platform_driver wm831x_backup_driver = {
 212         .probe = wm831x_backup_probe,
 213         .remove = __devexit_p(wm831x_backup_remove),
 214         .driver = {
 215                 .name = "wm831x-backup",
 216         },
 217 };
 218
 219 static int __init wm831x_backup_init(void)
 220 {
 221         return platform_driver_register(&wm831x_backup_driver);
 222 }
 223 module_init(wm831x_backup_init);
 224
 225 static void __exit wm831x_backup_exit(void)
 226 {
 227         platform_driver_unregister(&wm831x_backup_driver);
 228 }
 229 module_exit(wm831x_backup_exit);
 230
 231 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
 232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 233 MODULE_LICENSE("GPL");
 234 MODULE_ALIAS("platform:wm831x-backup");