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>

drivers/mfd/wm831x-core.c

@@ -793,6 +793,9 @@ static struct resource wm831x_wdt_resources[] = {
 };
 
 static struct mfd_cell wm8310_devs[] = {
+	{
+		.name = "wm831x-backup",
+	},
 	{
 		.name = "wm831x-buckv",
 		.id = 1,
@@ -946,6 +949,9 @@ static struct mfd_cell wm8310_devs[] = {
 };
 
 static struct mfd_cell wm8311_devs[] = {
+	{
+		.name = "wm831x-backup",
+	},
 	{
 		.name = "wm831x-buckv",
 		.id = 1,
@@ -1080,6 +1086,9 @@ static struct mfd_cell wm8311_devs[] = {
 };
 
 static struct mfd_cell wm8312_devs[] = {
+	{
+		.name = "wm831x-backup",
+	},
 	{
 		.name = "wm831x-buckv",
 		.id = 1,

drivers/power/Kconfig

@@ -29,6 +29,13 @@ config APM_POWER
 	  Say Y here to enable support APM status emulation using
 	  battery class devices.
 
+config WM831X_BACKUP
+	tristate "WM831X backup battery charger support"
+	depends on MFD_WM831X
+	help
+	  Say Y here to enable support for the backup battery charger
+	  in the Wolfson Microelectronics WM831x PMICs.
+
 config WM831X_POWER
 	tristate "WM831X PMU support"
 	depends on MFD_WM831X

drivers/power/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
 
 obj-$(CONFIG_PDA_POWER)		+= pda_power.o
 obj-$(CONFIG_APM_POWER)		+= apm_power.o
+obj-$(CONFIG_WM831X_BACKUP)	+= wm831x_backup.o
 obj-$(CONFIG_WM831X_POWER)	+= wm831x_power.o
 obj-$(CONFIG_WM8350_POWER)	+= wm8350_power.o
 

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");