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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Backup battery driver for Wolfson Microelectronics wm831x PMICs4 *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 19struct wm831x_backup {20 struct wm831x *wm831x;21 struct power_supply *backup;22 struct power_supply_desc backup_desc;23 char name[20];24};25 26static 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 properties41 *********************************************************************/42 43static 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 112static 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 else129 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 else141 val->intval = 0;142 break;143 144 default:145 ret = -EINVAL;146 break;147 }148 149 return ret;150}151 152static 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 * Initialisation160 *********************************************************************/161 162static 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 read176 * back the status without enabling the charger (which may177 * 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 else185 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 199static struct platform_driver wm831x_backup_driver = {200 .probe = wm831x_backup_probe,201 .driver = {202 .name = "wm831x-backup",203 },204};205 206module_platform_driver(wm831x_backup_driver);207 208MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");209MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");210MODULE_LICENSE("GPL");211MODULE_ALIAS("platform:wm831x-backup");212