power: implement platform battery driver

This driver can be used for dumb batteries when all knowledge about
their state belongs to the platform that does necessary ADC readings,
conversions, guessimations etc.

Signed-off-by: Paul Fertser <fercerpav@gmail.com>

4 files changed, 138 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index bdbc4f73fcd..5382c108db0 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -103,4 +103,10 @@ config CHARGER_PCF50633
 	help
 	 Say Y to include support for NXP PCF50633 Main Battery Charger.
 
+config BATTERY_PLATFORM
+	tristate "Platform battery driver"
+	help
+	  Say Y here to include support for battery driver that gets all
+	  information from platform functions.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 380d17c9ae2..b962d1a9031 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_BATTERY_BQ27x00)	+= bq27x00_battery.o
 obj-$(CONFIG_BATTERY_DA9030)	+= da9030_battery.o
 obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
 obj-$(CONFIG_CHARGER_PCF50633)	+= pcf50633-charger.o
+obj-$(CONFIG_BATTERY_PLATFORM)	+= platform_battery.o
diff --git a/drivers/power/platform_battery.c b/drivers/power/platform_battery.c
new file mode 100644
index 00000000000..99e155a2057
--- /dev/null
+++ b/drivers/power/platform_battery.c
@@ -0,0 +1,119 @@
+/*
+ * Driver for platform battery
+ *
+ * Copyright (c) Paul Fertser <fercerpav@gmail.com>
+ * Inspired by Balaji Rao <balajirrao@openmoko.org>
+ *
+ * This driver can be used for dumb batteries when all knowledge about
+ * their state belongs to the platform that does necessary ADC readings,
+ * conversions, guessimations etc.
+ *
+ * Use consistent with the GNU GPL is permitted, provided that this
+ * copyright notice is preserved in its entirety in all copies and derived
+ * works.
+ */
+
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/platform_battery.h>
+
+struct platform_battery {
+	struct power_supply psy;
+	struct platform_bat_platform_data *pdata;
+};
+
+static int platform_bat_get_property(struct power_supply *psy,
+				       enum power_supply_property psp,
+				       union power_supply_propval *val)
+{
+	struct platform_battery *bat =
+				container_of(psy, struct platform_battery, psy);
+	size_t i;
+	int present=1;
+
+	if (bat->pdata->is_present)
+		present = bat->pdata->is_present();
+
+	if (psp != POWER_SUPPLY_PROP_PRESENT && !present)
+		return -ENODEV;
+
+	for (i = 0; i < psy->num_properties; i++)
+		if (psy->properties[i] == psp) {
+			val->intval = bat->pdata->get_property[i]();
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+static void platform_bat_ext_changed(struct power_supply *psy)
+{
+	struct platform_battery *bat =
+				container_of(psy, struct platform_battery, psy);
+	power_supply_changed(&bat->psy);
+}
+
+static int platform_battery_probe(struct platform_device *pdev)
+{
+	struct platform_battery *platform_bat;
+	struct platform_bat_platform_data *pdata =
+		(struct platform_bat_platform_data *)pdev->dev.platform_data;
+
+	platform_bat = kzalloc(sizeof(*platform_bat), GFP_KERNEL);
+	if (!platform_bat)
+		return -ENOMEM;
+
+	if (pdata->name)
+		platform_bat->psy.name = pdata->name;
+	else
+		platform_bat->psy.name = dev_name(&pdev->dev);
+	platform_bat->psy.type = POWER_SUPPLY_TYPE_BATTERY;
+	platform_bat->psy.properties = pdata->properties;
+	platform_bat->psy.num_properties = pdata->num_properties;
+	platform_bat->psy.get_property = platform_bat_get_property;
+	platform_bat->psy.external_power_changed = platform_bat_ext_changed;
+
+	platform_bat->pdata = pdata;
+	platform_set_drvdata(pdev, platform_bat);
+	power_supply_register(&pdev->dev, &platform_bat->psy);
+
+	return 0;
+}
+
+static int platform_battery_remove(struct platform_device *pdev)
+{
+	struct platform_battery *bat = platform_get_drvdata(pdev);
+
+	power_supply_unregister(&bat->psy);
+	kfree(bat);
+
+	return 0;
+}
+
+static struct platform_driver platform_battery_driver = {
+	.driver = {
+		.name = "platform_battery",
+	},
+	.probe	  = platform_battery_probe,
+	.remove   = platform_battery_remove,
+};
+
+static int __init platform_battery_init(void)
+{
+	return platform_driver_register(&platform_battery_driver);
+}
+module_init(platform_battery_init);
+
+static void __exit platform_battery_exit(void)
+{
+	platform_driver_unregister(&platform_battery_driver);
+}
+module_exit(platform_battery_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul Fertser <fercerpav@gmail.com>");
+MODULE_DESCRIPTION("platform battery driver");
diff --git a/include/linux/platform_battery.h b/include/linux/platform_battery.h
new file mode 100644
index 00000000000..00f7651096a
--- /dev/null
+++ b/include/linux/platform_battery.h
@@ -0,0 +1,12 @@
+#ifndef __PLATFORM_BATTERY_H__
+#define __PLATFORM_BATTERY_H__
+
+struct platform_bat_platform_data {
+	const char *name;
+	int (**get_property)(void);
+	int (*is_present)(void);
+	enum power_supply_property *properties;
+	size_t num_properties;
+};
+
+#endif