drivers/power/supply/wm831x_backup.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Backup battery driver for Wolfson Microelectronics wm831x PMICs
   4  *
   5  * Copyright 2009 Wolfson Microelectronics PLC.
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/err.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/power_supply.h>
  12 #include <linux/slab.h>
  13
  14 #include <linux/mfd/wm831x/core.h>
  15 #include <linux/mfd/wm831x/auxadc.h>
  16 #include <linux/mfd/wm831x/pmu.h>
  17 #include <linux/mfd/wm831x/pdata.h>
  18
  19 struct wm831x_backup {
  20         struct wm831x *wm831x;
  21         struct power_supply *backup;
  22         struct power_supply_desc backup_desc;
  23         char name[20];
  24 };
  25
  26 static int wm831x_backup_read_voltage(struct wm831x *wm831x,
  27                                      enum wm831x_auxadc src,
  28                                      union power_supply_propval *val)
  29 {
  30         int ret;
  31
  32         ret = wm831x_auxadc_read_uv(wm831x, src);
  33         if (ret >= 0)
  34                 val->intval = ret;
  35
  36         return ret;
  37 }
  38
  39 /*********************************************************************
  40  *              Backup supply properties
  41  *********************************************************************/
  42
  43 static void wm831x_config_backup(struct wm831x *wm831x)
  44 {
  45         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
  46         struct wm831x_backup_pdata *pdata;
  47         int ret, reg;
  48
  49         if (!wm831x_pdata || !wm831x_pdata->backup) {
  50                 dev_warn(wm831x->dev,
  51                          "No backup battery charger configuration\n");
  52                 return;
  53         }
  54
  55         pdata = wm831x_pdata->backup;
  56
  57         reg = 0;
  58
  59         if (pdata->charger_enable)
  60                 reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
  61         if (pdata->no_constant_voltage)
  62                 reg |= WM831X_BKUP_CHG_MODE;
  63
  64         switch (pdata->vlim) {
  65         case 2500:
  66                 break;
  67         case 3100:
  68                 reg |= WM831X_BKUP_CHG_VLIM;
  69                 break;
  70         default:
  71                 dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
  72                         pdata->vlim);
  73         }
  74
  75         switch (pdata->ilim) {
  76         case 100:
  77                 break;
  78         case 200:
  79                 reg |= 1;
  80                 break;
  81         case 300:
  82                 reg |= 2;
  83                 break;
  84         case 400:
  85                 reg |= 3;
  86                 break;
  87         default:
  88                 dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
  89                         pdata->ilim);
  90         }
  91
  92         ret = wm831x_reg_unlock(wm831x);
  93         if (ret != 0) {
  94                 dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
  95                 return;
  96         }
  97
  98         ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
  99                               WM831X_BKUP_CHG_ENA_MASK |
 100                               WM831X_BKUP_CHG_MODE_MASK |
 101                               WM831X_BKUP_BATT_DET_ENA_MASK |
 102                               WM831X_BKUP_CHG_VLIM_MASK |
 103                               WM831X_BKUP_CHG_ILIM_MASK,
 104                               reg);
 105         if (ret != 0)
 106                 dev_err(wm831x->dev,
 107                         "Failed to set backup charger config: %d\n", ret);
 108
 109         wm831x_reg_lock(wm831x);
 110 }
 111
 112 static int wm831x_backup_get_prop(struct power_supply *psy,
 113                                   enum power_supply_property psp,
 114                                   union power_supply_propval *val)
 115 {
 116         struct wm831x_backup *devdata = dev_get_drvdata(psy->dev.parent);
 117         struct wm831x *wm831x = devdata->wm831x;
 118         int ret = 0;
 119
 120         ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
 121         if (ret < 0)
 122                 return ret;
 123
 124         switch (psp) {
 125         case POWER_SUPPLY_PROP_STATUS:
 126                 if (ret & WM831X_BKUP_CHG_STS)
 127                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
 128                 else
 129                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 130                 break;
 131
 132         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 133                 ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
 134                                                 val);
 135                 break;
 136
 137         case POWER_SUPPLY_PROP_PRESENT:
 138                 if (ret & WM831X_BKUP_CHG_STS)
 139                         val->intval = 1;
 140                 else
 141                         val->intval = 0;
 142                 break;
 143
 144         default:
 145                 ret = -EINVAL;
 146                 break;
 147         }
 148
 149         return ret;
 150 }
 151
 152 static enum power_supply_property wm831x_backup_props[] = {
 153         POWER_SUPPLY_PROP_STATUS,
 154         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 155         POWER_SUPPLY_PROP_PRESENT,
 156 };
 157
 158 /*********************************************************************
 159  *              Initialisation
 160  *********************************************************************/
 161
 162 static int wm831x_backup_probe(struct platform_device *pdev)
 163 {
 164         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 165         struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
 166         struct wm831x_backup *devdata;
 167
 168         devdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_backup),
 169                                 GFP_KERNEL);
 170         if (devdata == NULL)
 171                 return -ENOMEM;
 172
 173         devdata->wm831x = wm831x;
 174         platform_set_drvdata(pdev, devdata);
 175
 176         /* We ignore configuration failures since we can still read
 177          * back the status without enabling the charger (which may
 178          * already be enabled anyway).
 179          */
 180         wm831x_config_backup(wm831x);
 181
 182         if (wm831x_pdata && wm831x_pdata->wm831x_num)
 183                 snprintf(devdata->name, sizeof(devdata->name),
 184                          "wm831x-backup.%d", wm831x_pdata->wm831x_num);
 185         else
 186                 snprintf(devdata->name, sizeof(devdata->name),
 187                          "wm831x-backup");
 188
 189         devdata->backup_desc.name = devdata->name;
 190         devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 191         devdata->backup_desc.properties = wm831x_backup_props;
 192         devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props);
 193         devdata->backup_desc.get_property = wm831x_backup_get_prop;
 194         devdata->backup = power_supply_register(&pdev->dev,
 195                                                 &devdata->backup_desc, NULL);
 196
 197         return PTR_ERR_OR_ZERO(devdata->backup);
 198 }
 199
 200 static int wm831x_backup_remove(struct platform_device *pdev)
 201 {
 202         struct wm831x_backup *devdata = platform_get_drvdata(pdev);
 203
 204         power_supply_unregister(devdata->backup);
 205
 206         return 0;
 207 }
 208
 209 static struct platform_driver wm831x_backup_driver = {
 210         .probe = wm831x_backup_probe,
 211         .remove = wm831x_backup_remove,
 212         .driver = {
 213                 .name = "wm831x-backup",
 214         },
 215 };
 216
 217 module_platform_driver(wm831x_backup_driver);
 218
 219 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
 220 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 221 MODULE_LICENSE("GPL");
 222 MODULE_ALIAS("platform:wm831x-backup");