greybus: add battery module

drivers/staging/greybus/Makefile

@@ -6,7 +6,8 @@ greybus-y :=	core.o		\
 		i2c-gb.o	\
 		gpio-gb.o	\
 		sdio-gb.o	\
-		uart-gb.o
+		uart-gb.o	\
+		battery-gb.o
 
 obj-m += greybus.o
 obj-m += es1-ap-usb.o

drivers/staging/greybus/battery-gb.c

@@ -0,0 +1,153 @@
+/*
+ * Battery driver for a Greybus module.
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/power_supply.h>
+#include "greybus.h"
+
+struct gb_battery {
+	struct power_supply bat;
+	struct greybus_device *gdev;
+};
+#define to_gb_battery(x) container_of(x, struct gb_battery, bat)
+
+static const struct greybus_module_id id_table[] = {
+	{ GREYBUS_DEVICE(0x42, 0x42) },	/* make shit up */
+	{ },	/* terminating NULL entry */
+};
+
+static int get_status(struct gb_battery *gb)
+{
+	// FIXME!!!
+	return 0;
+}
+
+static int get_capacity(struct gb_battery *gb)
+{
+	// FIXME!!!
+	return 0;
+}
+
+static int get_temp(struct gb_battery *gb)
+{
+	// FIXME!!!
+	return 0;
+}
+
+static int get_voltage(struct gb_battery *gb)
+{
+	// FIXME!!!
+	return 0;
+}
+
+
+
+static int get_property(struct power_supply *b,
+			enum power_supply_property psp,
+			union power_supply_propval *val)
+{
+	struct gb_battery *gb = to_gb_battery(b);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		// FIXME - guess!
+		val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
+		break;
+
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = get_status(gb);
+		break;
+
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		val->intval = 4700000;	// FIXME - guess???
+		break;
+
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = get_capacity(gb);
+		break;
+
+	case POWER_SUPPLY_PROP_TEMP:
+		val->intval = get_temp(gb);
+		break;
+
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = get_voltage(gb);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
+// FIXME - verify this list, odds are some can be removed and others added.
+static enum power_supply_property battery_props[] = {
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+};
+
+int gb_battery_probe(struct greybus_device *gdev,
+		 const struct greybus_module_id *id)
+{
+	struct gb_battery *gb;
+	struct power_supply *b;
+	int retval;
+
+	gb = kzalloc(sizeof(*gb), GFP_KERNEL);
+	if (!gb)
+		return -ENOMEM;
+
+	b = &gb->bat;
+	// FIXME - get a better (i.e. unique) name
+	// FIXME - anything else needs to be set?
+	b->name			= "gb_battery";
+	b->type			= POWER_SUPPLY_TYPE_BATTERY,
+	b->properties		= battery_props,
+	b->num_properties	= ARRAY_SIZE(battery_props),
+	b->get_property		= get_property,
+
+	retval = power_supply_register(&gdev->dev, b);
+	if (retval) {
+		kfree(gb);
+		return retval;
+	}
+	gdev->gb_battery = gb;
+
+	return 0;
+}
+
+void gb_battery_disconnect(struct greybus_device *gdev)
+{
+	struct gb_battery *gb;
+
+	gb = gdev->gb_battery;
+
+	power_supply_unregister(&gb->bat);
+
+	kfree(gb);
+}
+
+#if 0
+static struct greybus_driver battery_gb_driver = {
+	.probe =	gb_battery_probe,
+	.disconnect =	gb_battery_disconnect,
+	.id_table =	id_table,
+};
+
+module_greybus_driver(battery_gb_driver);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");
+#endif

drivers/staging/greybus/core.c

@@ -210,8 +210,15 @@ static int gb_init_subdevs(struct greybus_device *gdev,
 	retval = gb_tty_probe(gdev, id);
 	if (retval)
 		goto error_tty;
+
+	retval = gb_battery_probe(gdev, id);
+	if (retval)
+		goto error_battery;
 	return 0;
 
+error_battery:
+	gb_tty_disconnect(gdev);
+
 error_tty:
 	gb_sdio_disconnect(gdev);
 
@@ -444,6 +451,7 @@ void greybus_remove_device(struct greybus_device *gdev)
 	gb_gpio_disconnect(gdev);
 	gb_sdio_disconnect(gdev);
 	gb_tty_disconnect(gdev);
+	gb_battery_disconnect(gdev);
 
 	// FIXME - device_remove(&gdev->dev);
 }

drivers/staging/greybus/greybus.h

@@ -91,6 +91,7 @@ struct gb_gpio_device;
 struct gb_sdio_host;
 struct gb_tty;
 struct gb_usb_device;
+struct gb_battery;
 struct greybus_host_device;
 struct svc_msg;
 
@@ -142,6 +143,7 @@ struct greybus_device {
 	struct gb_sdio_host *gb_sdio_host;
 	struct gb_tty *gb_tty;
 	struct gb_usb_device *gb_usb_dev;
+	struct gb_battery *gb_battery;
 };
 #define to_greybus_device(d) container_of(d, struct greybus_device, dev)
 
@@ -237,6 +239,8 @@ int gb_sdio_probe(struct greybus_device *gdev, const struct greybus_module_id *i
 void gb_sdio_disconnect(struct greybus_device *gdev);
 int gb_tty_probe(struct greybus_device *gdev, const struct greybus_module_id *id);
 void gb_tty_disconnect(struct greybus_device *gdev);
+int gb_battery_probe(struct greybus_device *gdev, const struct greybus_module_id *id);
+void gb_battery_disconnect(struct greybus_device *gdev);
 
 int gb_tty_init(void);
 void gb_tty_exit(void);