Quelle  wm831x_backup.c   Sprache: C

// 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 ");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-backup");