// 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");