wm831x: Factor out WM831x backup battery charger

The backup battery on WM831x is a separate IP block to the main PMU
and is largely unrelated to the main supply functionality. Factor it
out into a separate driver in order to reflect this and better support
future hardware versions.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

1 files changed, 233 insertions, 0 deletions

diff --git a/drivers/power/wm831x_backup.c b/drivers/power/wm831x_backup.c
new file mode 100644
index 000000000000..f181076a4085
--- /dev/null
+++ b/drivers/power/wm831x_backup.c
@@ -0,0 +1,233 @@
+/*
+ * 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/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;
+};
+
+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 __devinit int wm831x_backup_probe(struct platform_device *pdev)
+{
+        struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
+        struct wm831x_backup *devdata;
+        struct power_supply *backup;
+        int ret, irq, i;
+
+        devdata = kzalloc(sizeof(struct wm831x_backup), GFP_KERNEL);
+        if (devdata == NULL)
+                return -ENOMEM;
+
+        devdata->wm831x = wm831x;
+        platform_set_drvdata(pdev, devdata);
+
+        backup = &devdata->backup;
+
+        /* 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);
+
+        backup->name = "wm831x-backup";
+        backup->type = POWER_SUPPLY_TYPE_BATTERY;
+        backup->properties = wm831x_backup_props;
+        backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
+        backup->get_property = wm831x_backup_get_prop;
+        ret = power_supply_register(&pdev->dev, backup);
+        if (ret)
+                goto err_kmalloc;
+
+        return ret;
+
+err_kmalloc:
+        kfree(devdata);
+        return ret;
+}
+
+static __devexit int wm831x_backup_remove(struct platform_device *pdev)
+{
+        struct wm831x_backup *devdata = platform_get_drvdata(pdev);
+
+        power_supply_unregister(&devdata->backup);
+        kfree(devdata);
+
+        return 0;
+}
+
+static struct platform_driver wm831x_backup_driver = {
+        .probe = wm831x_backup_probe,
+        .remove = __devexit_p(wm831x_backup_remove),
+        .driver = {
+                .name = "wm831x-backup",
+        },
+};
+
+static int __init wm831x_backup_init(void)
+{
+        return platform_driver_register(&wm831x_backup_driver);
+}
+module_init(wm831x_backup_init);
+
+static void __exit wm831x_backup_exit(void)
+{
+        platform_driver_unregister(&wm831x_backup_driver);
+}
+module_exit(wm831x_backup_exit);
+
+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");