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         char name[20];
  26 };
  27
  28 static 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
  45 static 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
 114 static 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
 154 static 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
 164 static 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 = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_backup),
 173                                 GFP_KERNEL);
 174         if (devdata == NULL)
 175                 return -ENOMEM;
 176
 177         devdata->wm831x = wm831x;
 178         platform_set_drvdata(pdev, devdata);
 179
 180         backup = &devdata->backup;
 181
 182         /* We ignore configuration failures since we can still read
 183          * back the status without enabling the charger (which may
 184          * already be enabled anyway).
 185          */
 186         wm831x_config_backup(wm831x);
 187
 188         if (wm831x_pdata && wm831x_pdata->wm831x_num)
 189                 snprintf(devdata->name, sizeof(devdata->name),
 190                          "wm831x-backup.%d", wm831x_pdata->wm831x_num);
 191         else
 192                 snprintf(devdata->name, sizeof(devdata->name),
 193                          "wm831x-backup");
 194
 195         backup->name = devdata->name;
 196         backup->type = POWER_SUPPLY_TYPE_BATTERY;
 197         backup->properties = wm831x_backup_props;
 198         backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
 199         backup->get_property = wm831x_backup_get_prop;
 200         ret = power_supply_register(&pdev->dev, backup);
 201
 202         return ret;
 203 }
 204
 205 static int wm831x_backup_remove(struct platform_device *pdev)
 206 {
 207         struct wm831x_backup *devdata = platform_get_drvdata(pdev);
 208
 209         power_supply_unregister(&devdata->backup);
 210
 211         return 0;
 212 }
 213
 214 static struct platform_driver wm831x_backup_driver = {
 215         .probe = wm831x_backup_probe,
 216         .remove = wm831x_backup_remove,
 217         .driver = {
 218                 .name = "wm831x-backup",
 219         },
 220 };
 221
 222 module_platform_driver(wm831x_backup_driver);
 223
 224 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
 225 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 226 MODULE_LICENSE("GPL");
 227 MODULE_ALIAS("platform:wm831x-backup");