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// SPDX-License-Identifier: GPL-2.0-only
/*
* Backup battery driver for Wolfson Microelectronics wm831x PMICs
*
* Copyright 2009 Wolfson Microelectronics PLC.
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/auxadc.h>
#include <linux/mfd/wm831x/pmu.h>
#include <linux/mfd/wm831x/pdata.h>
struct wm831x_backup {
struct wm831x *wm831x;
struct power_supply *backup;
struct power_supply_desc backup_desc;
char name[20];
};
static int wm831x_backup_read_voltage(struct wm831x *wm831x,
enum wm831x_auxadc src,
union power_supply_propval *val)
{
int ret;
ret = wm831x_auxadc_read_uv(wm831x, src);
if (ret >= 0)
val->intval = ret;
return ret;
}
/*********************************************************************
* Backup supply properties
*********************************************************************/
static void wm831x_config_backup(struct wm831x *wm831x)
{
struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
struct wm831x_backup_pdata *pdata;
int ret, reg;
if (!wm831x_pdata || !wm831x_pdata->backup) {
dev_warn(wm831x->dev,
"No backup battery charger configuration\n");
return;
}
pdata = wm831x_pdata->backup;
reg = 0;
if (pdata->charger_enable)
reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
if (pdata->no_constant_voltage)
reg |= WM831X_BKUP_CHG_MODE;
switch (pdata->vlim) {
case 2500:
break;
case 3100:
reg |= WM831X_BKUP_CHG_VLIM;
break;
default:
dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
pdata->vlim);
}
switch (pdata->ilim) {
case 100:
break;
case 200:
reg |= 1;
break;
case 300:
reg |= 2;
break;
case 400:
reg |= 3;
break;
default:
dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
pdata->ilim);
}
ret = wm831x_reg_unlock(wm831x);
if (ret != 0) {
dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
return;
}
ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
WM831X_BKUP_CHG_ENA_MASK |
WM831X_BKUP_CHG_MODE_MASK |
WM831X_BKUP_BATT_DET_ENA_MASK |
WM831X_BKUP_CHG_VLIM_MASK |
WM831X_BKUP_CHG_ILIM_MASK,
reg);
if (ret != 0)
dev_err(wm831x->dev,
"Failed to set backup charger config: %d\n", ret);
wm831x_reg_lock(wm831x);
}
static int wm831x_backup_get_prop(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct wm831x_backup *devdata = dev_get_drvdata(psy->dev.parent);
struct wm831x *wm831x = devdata->wm831x;
int ret = 0;
ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
if (ret < 0)
return ret;
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
if (ret & WM831X_BKUP_CHG_STS)
val->intval = POWER_SUPPLY_STATUS_CHARGING;
else
val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
break;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
val);
break;
case POWER_SUPPLY_PROP_PRESENT:
if (ret & WM831X_BKUP_CHG_STS)
val->intval = 1;
else
val->intval = 0;
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static enum power_supply_property wm831x_backup_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_PRESENT,
};
/*********************************************************************
* Initialisation
*********************************************************************/
static int wm831x_backup_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
struct wm831x_backup *devdata;
devdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_backup),
GFP_KERNEL);
if (devdata == NULL)
return -ENOMEM;
devdata->wm831x = wm831x;
/* We ignore configuration failures since we can still read
* back the status without enabling the charger (which may
* already be enabled anyway).
*/
wm831x_config_backup(wm831x);
if (wm831x_pdata && wm831x_pdata->wm831x_num)
snprintf(devdata->name, sizeof(devdata->name),
"wm831x-backup.%d", wm831x_pdata->wm831x_num);
else
snprintf(devdata->name, sizeof(devdata->name),
"wm831x-backup");
devdata->backup_desc.name = devdata->name;
devdata->backup_desc.type = POWER_SUPPLY_TYPE_BATTERY;
devdata->backup_desc.properties = wm831x_backup_props;
devdata->backup_desc.num_properties = ARRAY_SIZE(wm831x_backup_props);
devdata->backup_desc.get_property = wm831x_backup_get_prop;
devdata->backup = devm_power_supply_register(&pdev->dev,
&devdata->backup_desc, NULL);
return PTR_ERR_OR_ZERO(devdata->backup);
}
static struct platform_driver wm831x_backup_driver = {
.probe = wm831x_backup_probe,
.driver = {
.name = "wm831x-backup",
},
};
module_platform_driver(wm831x_backup_driver);
MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-backup");
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