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"); 226