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; 174 175 /* We ignore configuration failures since we can still read 176 * back the status without enabling the charger (which may 177 * already be enabled anyway). 178 */ 179 wm831x_config_backup(wm831x); 180 181 if (wm831x_pdata && wm831x_pdata->wm831x_num) 182 snprintf(devdata->name, sizeof(devdata->name), 183 "wm831x-backup.%d", wm831x_pdata->wm831x_num); 184 else 185 snprintf(devdata->name, sizeof(devdata->name), 186 "wm831x-backup"); 187 188 devdata->backup_desc.name = devdata->name; 189 devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY; 190 devdata->backup_desc.properties = wm831x_backup_props; 191 devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props); 192 devdata->backup_desc.get_property = wm831x_backup_get_prop; 193 devdata->backup = devm_power_supply_register(&pdev->dev, 194 &devdata->backup_desc, NULL); 195 196 return PTR_ERR_OR_ZERO(devdata->backup); 197 } 198 199 static struct platform_driver wm831x_backup_driver = { 200 .probe = wm831x_backup_probe, 201 .driver = { 202 .name = "wm831x-backup", 203 }, 204 }; 205 206 module_platform_driver(wm831x_backup_driver); 207 208 MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs"); 209 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 210 MODULE_LICENSE("GPL"); 211 MODULE_ALIAS("platform:wm831x-backup"); 212