diff options
Diffstat (limited to 'drivers/power/supply/wm831x_backup.c')
| -rw-r--r-- | drivers/power/supply/wm831x_backup.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/drivers/power/supply/wm831x_backup.c b/drivers/power/supply/wm831x_backup.c new file mode 100644 index 000000000..2e33109ca --- /dev/null +++ b/drivers/power/supply/wm831x_backup.c @@ -0,0 +1,225 @@ +/* + * Backup battery driver for Wolfson Microelectronics wm831x PMICs + * + * Copyright 2009 Wolfson Microelectronics PLC. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#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; + platform_set_drvdata(pdev, devdata); + + /* 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 = power_supply_register(&pdev->dev, + &devdata->backup_desc, NULL); + + return PTR_ERR_OR_ZERO(devdata->backup); +} + +static int wm831x_backup_remove(struct platform_device *pdev) +{ + struct wm831x_backup *devdata = platform_get_drvdata(pdev); + + power_supply_unregister(devdata->backup); + + return 0; +} + +static struct platform_driver wm831x_backup_driver = { + .probe = wm831x_backup_probe, + .remove = wm831x_backup_remove, + .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"); |