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         struct power_supply_desc backup_desc;
  26         char name[20];
  27 };
  28
  29 static int wm831x_backup_read_voltage(struct wm831x *wm831x,
  30                                      enum wm831x_auxadc src,
  31                                      union power_supply_propval *val)
  32 {
  33         int ret;
  34
  35         ret = wm831x_auxadc_read_uv(wm831x, src);
  36         if (ret >= 0)
  37                 val->intval = ret;
  38
  39         return ret;
  40 }
  41
  42 /*********************************************************************
  43  *              Backup supply properties
  44  *********************************************************************/
  45
  46 static void wm831x_config_backup(struct wm831x *wm831x)
  47 {
  48         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
  49         struct wm831x_backup_pdata *pdata;
  50         int ret, reg;
  51
  52         if (!wm831x_pdata || !wm831x_pdata->backup) {
  53                 dev_warn(wm831x->dev,
  54                          "No backup battery charger configuration\n");
  55                 return;
  56         }
  57
  58         pdata = wm831x_pdata->backup;
  59
  60         reg = 0;
  61
  62         if (pdata->charger_enable)
  63                 reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
  64         if (pdata->no_constant_voltage)
  65                 reg |= WM831X_BKUP_CHG_MODE;
  66
  67         switch (pdata->vlim) {
  68         case 2500:
  69                 break;
  70         case 3100:
  71                 reg |= WM831X_BKUP_CHG_VLIM;
  72                 break;
  73         default:
  74                 dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
  75                         pdata->vlim);
  76         }
  77
  78         switch (pdata->ilim) {
  79         case 100:
  80                 break;
  81         case 200:
  82                 reg |= 1;
  83                 break;
  84         case 300:
  85                 reg |= 2;
  86                 break;
  87         case 400:
  88                 reg |= 3;
  89                 break;
  90         default:
  91                 dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
  92                         pdata->ilim);
  93         }
  94
  95         ret = wm831x_reg_unlock(wm831x);
  96         if (ret != 0) {
  97                 dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
  98                 return;
  99         }
 100
 101         ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
 102                               WM831X_BKUP_CHG_ENA_MASK |
 103                               WM831X_BKUP_CHG_MODE_MASK |
 104                               WM831X_BKUP_BATT_DET_ENA_MASK |
 105                               WM831X_BKUP_CHG_VLIM_MASK |
 106                               WM831X_BKUP_CHG_ILIM_MASK,
 107                               reg);
 108         if (ret != 0)
 109                 dev_err(wm831x->dev,
 110                         "Failed to set backup charger config: %d\n", ret);
 111
 112         wm831x_reg_lock(wm831x);
 113 }
 114
 115 static int wm831x_backup_get_prop(struct power_supply *psy,
 116                                   enum power_supply_property psp,
 117                                   union power_supply_propval *val)
 118 {
 119         struct wm831x_backup *devdata = dev_get_drvdata(psy->dev.parent);
 120         struct wm831x *wm831x = devdata->wm831x;
 121         int ret = 0;
 122
 123         ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
 124         if (ret < 0)
 125                 return ret;
 126
 127         switch (psp) {
 128         case POWER_SUPPLY_PROP_STATUS:
 129                 if (ret & WM831X_BKUP_CHG_STS)
 130                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
 131                 else
 132                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 133                 break;
 134
 135         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 136                 ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
 137                                                 val);
 138                 break;
 139
 140         case POWER_SUPPLY_PROP_PRESENT:
 141                 if (ret & WM831X_BKUP_CHG_STS)
 142                         val->intval = 1;
 143                 else
 144                         val->intval = 0;
 145                 break;
 146
 147         default:
 148                 ret = -EINVAL;
 149                 break;
 150         }
 151
 152         return ret;
 153 }
 154
 155 static enum power_supply_property wm831x_backup_props[] = {
 156         POWER_SUPPLY_PROP_STATUS,
 157         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 158         POWER_SUPPLY_PROP_PRESENT,
 159 };
 160
 161 /*********************************************************************
 162  *              Initialisation
 163  *********************************************************************/
 164
 165 static int wm831x_backup_probe(struct platform_device *pdev)
 166 {
 167         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 168         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
 169         struct wm831x_backup *devdata;
 170
 171         devdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_backup),
 172                                 GFP_KERNEL);
 173         if (devdata == NULL)
 174                 return -ENOMEM;
 175
 176         devdata->wm831x = wm831x;
 177         platform_set_drvdata(pdev, devdata);
 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         if (wm831x_pdata && wm831x_pdata->wm831x_num)
 186                 snprintf(devdata->name, sizeof(devdata->name),
 187                          "wm831x-backup.%d", wm831x_pdata->wm831x_num);
 188         else
 189                 snprintf(devdata->name, sizeof(devdata->name),
 190                          "wm831x-backup");
 191
 192         devdata->backup_desc.name = devdata->name;
 193         devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 194         devdata->backup_desc.properties = wm831x_backup_props;
 195         devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props);
 196         devdata->backup_desc.get_property = wm831x_backup_get_prop;
 197         devdata->backup = power_supply_register(&pdev->dev,
 198                                                 &devdata->backup_desc, NULL);
 199
 200         return PTR_ERR_OR_ZERO(devdata->backup);
 201 }
 202
 203 static int wm831x_backup_remove(struct platform_device *pdev)
 204 {
 205         struct wm831x_backup *devdata = platform_get_drvdata(pdev);
 206
 207         power_supply_unregister(devdata->backup);
 208
 209         return 0;
 210 }
 211
 212 static struct platform_driver wm831x_backup_driver = {
 213         .probe = wm831x_backup_probe,
 214         .remove = wm831x_backup_remove,
 215         .driver = {
 216                 .name = "wm831x-backup",
 217         },
 218 };
 219
 220 module_platform_driver(wm831x_backup_driver);
 221
 222 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
 223 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 224 MODULE_LICENSE("GPL");
 225 MODULE_ALIAS("platform:wm831x-backup");