Merge git://git.infradead.org/~dwmw2/battery-2.6

* git://git.infradead.org/~dwmw2/battery-2.6:
  [BATTERY] ds2760 W1 slave
  [BATTERY] One Laptop Per Child power/battery driver
  [BATTERY] Apple PMU driver
  [BATTERY] 1-Wire ds2760 chip battery driver
  [BATTERY] APM emulation driver for class batteries
  [BATTERY] pda_power platform driver
  [BATTERY] Universal power supply class (was: battery class)

21 files changed, 2958 insertions, 0 deletions

diff --git a/Documentation/power_supply_class.txt b/Documentation/power_supply_class.txt
new file mode 100644
index 00000000000..9758cf433c0
--- /dev/null
+++ b/Documentation/power_supply_class.txt
@@ -0,0 +1,167 @@
+Linux power supply class
+========================
+
+Synopsis
+~~~~~~~~
+Power supply class used to represent battery, UPS, AC or DC power supply
+properties to user-space.
+
+It defines core set of attributes, which should be applicable to (almost)
+every power supply out there. Attributes are available via sysfs and uevent
+interfaces.
+
+Each attribute has well defined meaning, up to unit of measure used. While
+the attributes provided are believed to be universally applicable to any
+power supply, specific monitoring hardware may not be able to provide them
+all, so any of them may be skipped.
+
+Power supply class is extensible, and allows to define drivers own attributes.
+The core attribute set is subject to the standard Linux evolution (i.e.
+if it will be found that some attribute is applicable to many power supply
+types or their drivers, it can be added to the core set).
+
+It also integrates with LED framework, for the purpose of providing
+typically expected feedback of battery charging/fully charged status and
+AC/USB power supply online status. (Note that specific details of the
+indication (including whether to use it at all) are fully controllable by
+user and/or specific machine defaults, per design principles of LED
+framework).
+
+
+Attributes/properties
+~~~~~~~~~~~~~~~~~~~~~
+Power supply class has predefined set of attributes, this eliminates code
+duplication across drivers. Power supply class insist on reusing its
+predefined attributes *and* their units.
+
+So, userspace gets predictable set of attributes and their units for any
+kind of power supply, and can process/present them to a user in consistent
+manner. Results for different power supplies and machines are also directly
+comparable.
+
+See drivers/power/ds2760_battery.c and drivers/power/pda_power.c for the
+example how to declare and handle attributes.
+
+
+Units
+~~~~~
+Quoting include/linux/power_supply.h:
+
+  All voltages, currents, charges, energies, time and temperatures in µV,
+  µA, µAh, µWh, seconds and tenths of degree Celsius unless otherwise
+  stated. It's driver's job to convert its raw values to units in which
+  this class operates.
+
+
+Attributes/properties detailed
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+~ ~ ~ ~ ~ ~ ~  Charge/Energy/Capacity - how to not confuse  ~ ~ ~ ~ ~ ~ ~
+~                                                                       ~
+~ Because both "charge" (µAh) and "energy" (µWh) represents "capacity"  ~
+~ of battery, this class distinguish these terms. Don't mix them!       ~
+~                                                                       ~
+~ CHARGE_* attributes represents capacity in µAh only.                  ~
+~ ENERGY_* attributes represents capacity in µWh only.                  ~
+~ CAPACITY attribute represents capacity in *percents*, from 0 to 100.  ~
+~                                                                       ~
+~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
+
+Postfixes:
+_AVG - *hardware* averaged value, use it if your hardware is really able to
+report averaged values.
+_NOW - momentary/instantaneous values.
+
+STATUS - this attribute represents operating status (charging, full,
+discharging (i.e. powering a load), etc.). This corresponds to
+BATTERY_STATUS_* values, as defined in battery.h.
+
+HEALTH - represents health of the battery, values corresponds to
+POWER_SUPPLY_HEALTH_*, defined in battery.h.
+
+VOLTAGE_MAX_DESIGN, VOLTAGE_MIN_DESIGN - design values for maximal and
+minimal power supply voltages. Maximal/minimal means values of voltages
+when battery considered "full"/"empty" at normal conditions. Yes, there is
+no direct relation between voltage and battery capacity, but some dumb
+batteries use voltage for very approximated calculation of capacity.
+Battery driver also can use this attribute just to inform userspace
+about maximal and minimal voltage thresholds of a given battery.
+
+CHARGE_FULL_DESIGN, CHARGE_EMPTY_DESIGN - design charge values, when
+battery considered full/empty.
+
+ENERGY_FULL_DESIGN, ENERGY_EMPTY_DESIGN - same as above but for energy.
+
+CHARGE_FULL, CHARGE_EMPTY - These attributes means "last remembered value
+of charge when battery became full/empty". It also could mean "value of
+charge when battery considered full/empty at given conditions (temperature,
+age)". I.e. these attributes represents real thresholds, not design values.
+
+ENERGY_FULL, ENERGY_EMPTY - same as above but for energy.
+
+CAPACITY - capacity in percents.
+CAPACITY_LEVEL - capacity level. This corresponds to
+POWER_SUPPLY_CAPACITY_LEVEL_*.
+
+TEMP - temperature of the power supply.
+TEMP_AMBIENT - ambient temperature.
+
+TIME_TO_EMPTY - seconds left for battery to be considered empty (i.e.
+while battery powers a load)
+TIME_TO_FULL - seconds left for battery to be considered full (i.e.
+while battery is charging)
+
+
+Battery <-> external power supply interaction
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Often power supplies are acting as supplies and supplicants at the same
+time. Batteries are good example. So, batteries usually care if they're
+externally powered or not.
+
+For that case, power supply class implements notification mechanism for
+batteries.
+
+External power supply (AC) lists supplicants (batteries) names in
+"supplied_to" struct member, and each power_supply_changed() call
+issued by external power supply will notify supplicants via
+external_power_changed callback.
+
+
+QA
+~~
+Q: Where is POWER_SUPPLY_PROP_XYZ attribute?
+A: If you cannot find attribute suitable for your driver needs, feel free
+   to add it and send patch along with your driver.
+
+   The attributes available currently are the ones currently provided by the
+   drivers written.
+
+   Good candidates to add in future: model/part#, cycle_time, manufacturer,
+   etc.
+
+
+Q: I have some very specific attribute (e.g. battery color), should I add
+   this attribute to standard ones?
+A: Most likely, no. Such attribute can be placed in the driver itself, if
+   it is useful. Of course, if the attribute in question applicable to
+   large set of batteries, provided by many drivers, and/or comes from
+   some general battery specification/standard, it may be a candidate to
+   be added to the core attribute set.
+
+
+Q: Suppose, my battery monitoring chip/firmware does not provides capacity
+   in percents, but provides charge_{now,full,empty}. Should I calculate
+   percentage capacity manually, inside the driver, and register CAPACITY
+   attribute? The same question about time_to_empty/time_to_full.
+A: Most likely, no. This class is designed to export properties which are
+   directly measurable by the specific hardware available.
+
+   Inferring not available properties using some heuristics or mathematical
+   model is not subject of work for a battery driver. Such functionality
+   should be factored out, and in fact, apm_power, the driver to serve
+   legacy APM API on top of power supply class, uses a simple heuristic of
+   approximating remaining battery capacity based on its charge, current,
+   voltage and so on. But full-fledged battery model is likely not subject
+   for kernel at all, as it would require floating point calculation to deal
+   with things like differential equations and Kalman filters. This is
+   better be handled by batteryd/libbattery, yet to be written.
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 4e6487d461f..7916f4b86d2 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -52,6 +52,8 @@ source "drivers/spi/Kconfig"
 
 source "drivers/w1/Kconfig"
 
+source "drivers/power/Kconfig"
+
 source "drivers/hwmon/Kconfig"
 
 source "drivers/mfd/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index adad2f3d438..503d8256944 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_I2O)		+= message/
 obj-$(CONFIG_RTC_LIB)		+= rtc/
 obj-y				+= i2c/
 obj-$(CONFIG_W1)		+= w1/
+obj-$(CONFIG_POWER_SUPPLY)	+= power/
 obj-$(CONFIG_HWMON)		+= hwmon/
 obj-$(CONFIG_PHONE)		+= telephony/
 obj-$(CONFIG_MD)		+= md/
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
new file mode 100644
index 00000000000..ab9c3e5a7c1
--- /dev/null
+++ b/drivers/power/Kconfig
@@ -0,0 +1,51 @@
+menuconfig POWER_SUPPLY
+	tristate "Power supply class support"
+	help
+	  Say Y here to enable power supply class support. This allows
+	  power supply (batteries, AC, USB) monitoring by userspace
+	  via sysfs and uevent (if available) and/or APM kernel interface
+	  (if selected below).
+
+if POWER_SUPPLY
+
+config POWER_SUPPLY_DEBUG
+	bool "Power supply debug"
+	help
+	  Say Y here to enable debugging messages for power supply class
+	  and drivers.
+
+config PDA_POWER
+	tristate "Generic PDA/phone power driver"
+	help
+	  Say Y here to enable generic power driver for PDAs and phones with
+	  one or two external power supplies (AC/USB) connected to main and
+	  backup batteries, and optional builtin charger.
+
+config APM_POWER
+	tristate "APM emulation for class batteries"
+	depends on APM_EMULATION
+	help
+	  Say Y here to enable support APM status emulation using
+	  battery class devices.
+
+config BATTERY_DS2760
+	tristate "DS2760 battery driver (HP iPAQ & others)"
+	select W1
+	select W1_SLAVE_DS2760
+	help
+	  Say Y here to enable support for batteries with ds2760 chip.
+
+config BATTERY_PMU
+	tristate "Apple PMU battery"
+	depends on ADB_PMU
+	help
+	  Say Y here to expose battery information on Apple machines
+	  through the generic battery class.
+
+config BATTERY_OLPC
+	tristate "One Laptop Per Child battery"
+	depends on X86_32 && OLPC
+	help
+	  Say Y to enable support for the battery on the OLPC laptop.
+
+endif # POWER_SUPPLY
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
new file mode 100644
index 00000000000..6413ded5fe5
--- /dev/null
+++ b/drivers/power/Makefile
@@ -0,0 +1,22 @@
+power_supply-objs := power_supply_core.o
+
+ifeq ($(CONFIG_SYSFS),y)
+power_supply-objs += power_supply_sysfs.o
+endif
+
+ifeq ($(CONFIG_LEDS_TRIGGERS),y)
+power_supply-objs += power_supply_leds.o
+endif
+
+ifeq ($(CONFIG_POWER_SUPPLY_DEBUG),y)
+EXTRA_CFLAGS += -DDEBUG
+endif
+
+obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
+
+obj-$(CONFIG_PDA_POWER)		+= pda_power.o
+obj-$(CONFIG_APM_POWER)		+= apm_power.o
+
+obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o
+obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o
+obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o
diff --git a/drivers/power/apm_power.c b/drivers/power/apm_power.c
new file mode 100644
index 00000000000..042bd950d03
--- /dev/null
+++ b/drivers/power/apm_power.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright © 2007 Anton Vorontsov <cbou@mail.ru>
+ * Copyright © 2007 Eugeny Boger <eugenyboger@dgap.mipt.ru>
+ *
+ * Author: Eugeny Boger <eugenyboger@dgap.mipt.ru>
+ *
+ * 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/power_supply.h>
+#include <linux/apm-emulation.h>
+
+#define PSY_PROP(psy, prop, val) psy->get_property(psy, \
+			 POWER_SUPPLY_PROP_##prop, val)
+
+#define _MPSY_PROP(prop, val) main_battery->get_property(main_battery, \
+							 prop, val)
+
+#define MPSY_PROP(prop, val) _MPSY_PROP(POWER_SUPPLY_PROP_##prop, val)
+
+static struct power_supply *main_battery;
+
+static void find_main_battery(void)
+{
+	struct device *dev;
+	struct power_supply *bat, *batm;
+	union power_supply_propval full;
+	int max_charge = 0;
+
+	main_battery = NULL;
+	batm = NULL;
+	list_for_each_entry(dev, &power_supply_class->devices, node) {
+		bat = dev_get_drvdata(dev);
+		/* If none of battery devices cantains 'use_for_apm' flag,
+		   choice one with maximum design charge */
+		if (!PSY_PROP(bat, CHARGE_FULL_DESIGN, &full)) {
+			if (full.intval > max_charge) {
+				batm = bat;
+				max_charge = full.intval;
+			}
+		}
+
+		if (bat->use_for_apm)
+			main_battery = bat;
+	}
+	if (!main_battery)
+		main_battery = batm;
+
+	return;
+}
+
+static int calculate_time(int status)
+{
+	union power_supply_propval charge_full, charge_empty;
+	union power_supply_propval charge, I;
+
+	if (MPSY_PROP(CHARGE_FULL, &charge_full)) {
+		/* if battery can't report this property, use design value */
+		if (MPSY_PROP(CHARGE_FULL_DESIGN, &charge_full))
+			return -1;
+	}
+
+	if (MPSY_PROP(CHARGE_EMPTY, &charge_empty)) {
+		/* if battery can't report this property, use design value */
+		if (MPSY_PROP(CHARGE_EMPTY_DESIGN, &charge_empty))
+			charge_empty.intval = 0;
+	}
+
+	if (MPSY_PROP(CHARGE_AVG, &charge)) {
+		/* if battery can't report average value, use momentary */
+		if (MPSY_PROP(CHARGE_NOW, &charge))
+			return -1;
+	}
+
+	if (MPSY_PROP(CURRENT_AVG, &I)) {
+		/* if battery can't report average value, use momentary */
+		if (MPSY_PROP(CURRENT_NOW, &I))
+			return -1;
+	}
+
+	if (status == POWER_SUPPLY_STATUS_CHARGING)
+		return ((charge.intval - charge_full.intval) * 60L) /
+		       I.intval;
+	else
+		return -((charge.intval - charge_empty.intval) * 60L) /
+			I.intval;
+}
+
+static int calculate_capacity(int using_charge)
+{
+	enum power_supply_property full_prop, empty_prop;
+	enum power_supply_property full_design_prop, empty_design_prop;
+	enum power_supply_property now_prop, avg_prop;
+	union power_supply_propval empty, full, cur;
+	int ret;
+
+	if (using_charge) {
+		full_prop = POWER_SUPPLY_PROP_CHARGE_FULL;
+		empty_prop = POWER_SUPPLY_PROP_CHARGE_EMPTY;
+		full_design_prop = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
+		empty_design_prop = POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN;
+		now_prop = POWER_SUPPLY_PROP_CHARGE_NOW;
+		avg_prop = POWER_SUPPLY_PROP_CHARGE_AVG;
+	} else {
+		full_prop = POWER_SUPPLY_PROP_ENERGY_FULL;
+		empty_prop = POWER_SUPPLY_PROP_ENERGY_EMPTY;
+		full_design_prop = POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN;
+		empty_design_prop = POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN;
+		now_prop = POWER_SUPPLY_PROP_ENERGY_NOW;
+		avg_prop = POWER_SUPPLY_PROP_ENERGY_AVG;
+	}
+
+	if (_MPSY_PROP(full_prop, &full)) {
+		/* if battery can't report this property, use design value */
+		if (_MPSY_PROP(full_design_prop, &full))
+			return -1;
+	}
+
+	if (_MPSY_PROP(avg_prop, &cur)) {
+		/* if battery can't report average value, use momentary */
+		if (_MPSY_PROP(now_prop, &cur))
+			return -1;
+	}
+
+	if (_MPSY_PROP(empty_prop, &empty)) {
+		/* if battery can't report this property, use design value */
+		if (_MPSY_PROP(empty_design_prop, &empty))
+			empty.intval = 0;
+	}
+
+	if (full.intval - empty.intval)
+		ret =  ((cur.intval - empty.intval) * 100L) /
+		       (full.intval - empty.intval);
+	else
+		return -1;
+
+	if (ret > 100)
+		return 100;
+	else if (ret < 0)
+		return 0;
+
+	return ret;
+}
+
+static void apm_battery_apm_get_power_status(struct apm_power_info *info)
+{
+	union power_supply_propval status;
+	union power_supply_propval capacity, time_to_full, time_to_empty;
+
+	down(&power_supply_class->sem);
+	find_main_battery();
+	if (!main_battery) {
+		up(&power_supply_class->sem);
+		return;
+	}
+
+	/* status */
+
+	if (MPSY_PROP(STATUS, &status))
+		status.intval = POWER_SUPPLY_STATUS_UNKNOWN;
+
+	/* ac line status */
+
+	if ((status.intval == POWER_SUPPLY_STATUS_CHARGING) ||
+	    (status.intval == POWER_SUPPLY_STATUS_NOT_CHARGING) ||
+	    (status.intval == POWER_SUPPLY_STATUS_FULL))
+		info->ac_line_status = APM_AC_ONLINE;
+	else
+		info->ac_line_status = APM_AC_OFFLINE;
+
+	/* battery life (i.e. capacity, in percents) */
+
+	if (MPSY_PROP(CAPACITY, &capacity) == 0) {
+		info->battery_life = capacity.intval;
+	} else {
+		/* try calculate using energy */
+		info->battery_life = calculate_capacity(0);
+		/* if failed try calculate using charge instead */
+		if (info->battery_life == -1)
+			info->battery_life = calculate_capacity(1);
+	}
+
+	/* charging status */
+
+	if (status.intval == POWER_SUPPLY_STATUS_CHARGING) {
+		info->battery_status = APM_BATTERY_STATUS_CHARGING;
+	} else {
+		if (info->battery_life > 50)
+			info->battery_status = APM_BATTERY_STATUS_HIGH;
+		else if (info->battery_life > 5)
+			info->battery_status = APM_BATTERY_STATUS_LOW;
+		else
+			info->battery_status = APM_BATTERY_STATUS_CRITICAL;
+	}
+	info->battery_flag = info->battery_status;
+
+	/* time */
+
+	info->units = APM_UNITS_MINS;
+
+	if (status.intval == POWER_SUPPLY_STATUS_CHARGING) {
+		if (MPSY_PROP(TIME_TO_FULL_AVG, &time_to_full)) {
+			if (MPSY_PROP(TIME_TO_FULL_NOW, &time_to_full))
+				info->time = calculate_time(status.intval);
+			else
+				info->time = time_to_full.intval / 60;
+		}
+	} else {
+		if (MPSY_PROP(TIME_TO_EMPTY_AVG, &time_to_empty)) {
+			if (MPSY_PROP(TIME_TO_EMPTY_NOW, &time_to_empty))
+				info->time = calculate_time(status.intval);
+			else
+				info->time = time_to_empty.intval / 60;
+		}
+	}
+
+	up(&power_supply_class->sem);
+	return;
+}
+
+static int __init apm_battery_init(void)
+{
+	printk(KERN_INFO "APM Battery Driver\n");
+
+	apm_get_power_status = apm_battery_apm_get_power_status;
+	return 0;
+}
+
+static void __exit apm_battery_exit(void)
+{
+	apm_get_power_status = NULL;
+	return;
+}
+
+module_init(apm_battery_init);
+module_exit(apm_battery_exit);
+
+MODULE_AUTHOR("Eugeny Boger <eugenyboger@dgap.mipt.ru>");
+MODULE_DESCRIPTION("APM emulation driver for battery monitoring class");
+MODULE_LICENSE("GPL");
diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c
new file mode 100644
index 00000000000..00e1ea6f1de
--- /dev/null
+++ b/drivers/power/ds2760_battery.c
@@ -0,0 +1,470 @@
+/*
+ * Driver for batteries with DS2760 chips inside.
+ *
+ * Copyright © 2007 Anton Vorontsov
+ *	       2004-2007 Matt Reimer
+ *	       2004 Szabolcs Gyurko
+ *
+ * Use consistent with the GNU GPL is permitted,
+ * provided that this copyright notice is
+ * preserved in its entirety in all copies and derived works.
+ *
+ * Author:  Anton Vorontsov <cbou@mail.ru>
+ *	    February 2007
+ *
+ *	    Matt Reimer <mreimer@vpop.net>
+ *	    April 2004, 2005, 2007
+ *
+ *	    Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
+ *	    September 2004
+ */
+
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/jiffies.h>
+#include <linux/workqueue.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+
+#include "../w1/w1.h"
+#include "../w1/slaves/w1_ds2760.h"
+
+struct ds2760_device_info {
+	struct device *dev;
+
+	/* DS2760 data, valid after calling ds2760_battery_read_status() */
+	unsigned long update_time;	/* jiffies when data read */
+	char raw[DS2760_DATA_SIZE];	/* raw DS2760 data */
+	int voltage_raw;		/* units of 4.88 mV */
+	int voltage_uV;			/* units of µV */
+	int current_raw;		/* units of 0.625 mA */
+	int current_uA;			/* units of µA */
+	int accum_current_raw;		/* units of 0.25 mAh */
+	int accum_current_uAh;		/* units of µAh */
+	int temp_raw;			/* units of 0.125 °C */
+	int temp_C;			/* units of 0.1 °C */
+	int rated_capacity;		/* units of µAh */
+	int rem_capacity;		/* percentage */
+	int full_active_uAh;		/* units of µAh */
+	int empty_uAh;			/* units of µAh */
+	int life_sec;			/* units of seconds */
+	int charge_status;		/* POWER_SUPPLY_STATUS_* */
+
+	int full_counter;
+	struct power_supply bat;
+	struct device *w1_dev;
+	struct workqueue_struct *monitor_wqueue;
+	struct delayed_work monitor_work;
+};
+
+static unsigned int cache_time = 1000;
+module_param(cache_time, uint, 0644);
+MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
+
+/* Some batteries have their rated capacity stored a N * 10 mAh, while
+ * others use an index into this table. */
+static int rated_capacities[] = {
+	0,
+	920,	/* Samsung */
+	920,	/* BYD */
+	920,	/* Lishen */
+	920,	/* NEC */
+	1440,	/* Samsung */
+	1440,	/* BYD */
+	1440,	/* Lishen */
+	1440,	/* NEC */
+	2880,	/* Samsung */
+	2880,	/* BYD */
+	2880,	/* Lishen */
+	2880	/* NEC */
+};
+
+/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
+ * temp is in Celsius */
+static int battery_interpolate(int array[], int temp)
+{
+	int index, dt;
+
+	if (temp <= 0)
+		return array[0];
+	if (temp >= 40)
+		return array[4];
+
+	index = temp / 10;
+	dt    = temp % 10;
+
+	return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
+}
+
+static int ds2760_battery_read_status(struct ds2760_device_info *di)
+{
+	int ret, i, start, count, scale[5];
+
+	if (di->update_time && time_before(jiffies, di->update_time +
+					   msecs_to_jiffies(cache_time)))
+		return 0;
+
+	/* The first time we read the entire contents of SRAM/EEPROM,
+	 * but after that we just read the interesting bits that change. */
+	if (di->update_time == 0) {
+		start = 0;
+		count = DS2760_DATA_SIZE;
+	} else {
+		start = DS2760_VOLTAGE_MSB;
+		count = DS2760_TEMP_LSB - start + 1;
+	}
+
+	ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
+	if (ret != count) {
+		dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
+			 di->w1_dev);
+		return 1;
+	}
+
+	di->update_time = jiffies;
+
+	/* DS2760 reports voltage in units of 4.88mV, but the battery class
+	 * reports in units of uV, so convert by multiplying by 4880. */
+	di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
+			  (di->raw[DS2760_VOLTAGE_LSB] >> 5);
+	di->voltage_uV = di->voltage_raw * 4880;
+
+	/* DS2760 reports current in signed units of 0.625mA, but the battery
+	 * class reports in units of µA, so convert by multiplying by 625. */
+	di->current_raw =
+	    (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
+			  (di->raw[DS2760_CURRENT_LSB] >> 3);
+	di->current_uA = di->current_raw * 625;
+
+	/* DS2760 reports accumulated current in signed units of 0.25mAh. */
+	di->accum_current_raw =
+	    (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
+			   di->raw[DS2760_CURRENT_ACCUM_LSB];
+	di->accum_current_uAh = di->accum_current_raw * 250;
+
+	/* DS2760 reports temperature in signed units of 0.125°C, but the
+	 * battery class reports in units of 1/10 °C, so we convert by
+	 * multiplying by .125 * 10 = 1.25. */
+	di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
+				     (di->raw[DS2760_TEMP_LSB] >> 5);
+	di->temp_C = di->temp_raw + (di->temp_raw / 4);
+
+	/* At least some battery monitors (e.g. HP iPAQ) store the battery's
+	 * maximum rated capacity. */
+	if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
+		di->rated_capacity = rated_capacities[
+			(unsigned int)di->raw[DS2760_RATED_CAPACITY]];
+	else
+		di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
+
+	di->rated_capacity *= 1000; /* convert to µAh */
+
+	/* Calculate the full level at the present temperature. */
+	di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
+			      di->raw[DS2760_ACTIVE_FULL + 1];
+
+	scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
+		   di->raw[DS2760_ACTIVE_FULL + 1];
+	for (i = 1; i < 5; i++)
+		scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
+
+	di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
+	di->full_active_uAh *= 1000; /* convert to µAh */
+
+	/* Calculate the empty level at the present temperature. */
+	scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
+	for (i = 3; i >= 0; i--)
+		scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
+
+	di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
+	di->empty_uAh *= 1000; /* convert to µAh */
+
+	/* From Maxim Application Note 131: remaining capacity =
+	 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
+	di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
+			    (di->full_active_uAh - di->empty_uAh);
+
+	if (di->rem_capacity < 0)
+		di->rem_capacity = 0;
+	if (di->rem_capacity > 100)
+		di->rem_capacity = 100;
+
+	if (di->current_uA)
+		di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
+				 3600L) / di->current_uA;
+	else
+		di->life_sec = 0;
+
+	return 0;
+}
+
+static void ds2760_battery_update_status(struct ds2760_device_info *di)
+{
+	int old_charge_status = di->charge_status;
+
+	ds2760_battery_read_status(di);
+
+	if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
+		di->full_counter = 0;
+
+	if (power_supply_am_i_supplied(&di->bat)) {
+		if (di->current_uA > 10000) {
+			di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
+			di->full_counter = 0;
+		} else if (di->current_uA < -5000) {
+			if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
+				dev_notice(di->dev, "not enough power to "
+					   "charge\n");
+			di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			di->full_counter = 0;
+		} else if (di->current_uA < 10000 &&
+			    di->charge_status != POWER_SUPPLY_STATUS_FULL) {
+
+			/* Don't consider the battery to be full unless
+			 * we've seen the current < 10 mA at least two
+			 * consecutive times. */
+
+			di->full_counter++;
+
+			if (di->full_counter < 2) {
+				di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
+			} else {
+				unsigned char acr[2];
+				int acr_val;
+
+				/* acr is in units of 0.25 mAh */
+				acr_val = di->full_active_uAh * 4L / 1000;
+
+				acr[0] = acr_val >> 8;
+				acr[1] = acr_val & 0xff;
+
+				if (w1_ds2760_write(di->w1_dev, acr,
+				    DS2760_CURRENT_ACCUM_MSB, 2) < 2)
+					dev_warn(di->dev,
+						 "ACR reset failed\n");
+
+				di->charge_status = POWER_SUPPLY_STATUS_FULL;
+			}
+		}
+	} else {
+		di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
+		di->full_counter = 0;
+	}
+
+	if (di->charge_status != old_charge_status)
+		power_supply_changed(&di->bat);
+
+	return;
+}
+
+static void ds2760_battery_work(struct work_struct *work)
+{
+	struct ds2760_device_info *di = container_of(work,
+		struct ds2760_device_info, monitor_work.work);
+	const int interval = HZ * 60;
+
+	dev_dbg(di->dev, "%s\n", __FUNCTION__);
+
+	ds2760_battery_update_status(di);
+	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
+
+	return;
+}
+
+#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
+					      bat);
+
+static void ds2760_battery_external_power_changed(struct power_supply *psy)
+{
+	struct ds2760_device_info *di = to_ds2760_device_info(psy);
+
+	dev_dbg(di->dev, "%s\n", __FUNCTION__);
+
+	cancel_delayed_work(&di->monitor_work);
+	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
+
+	return;
+}
+
+static int ds2760_battery_get_property(struct power_supply *psy,
+				       enum power_supply_property psp,
+				       union power_supply_propval *val)
+{
+	struct ds2760_device_info *di = to_ds2760_device_info(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = di->charge_status;
+		return 0;
+	default:
+		break;
+	}
+
+	ds2760_battery_read_status(di);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = di->voltage_uV;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		val->intval = di->current_uA;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		val->intval = di->rated_capacity;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		val->intval = di->full_active_uAh;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
+		val->intval = di->empty_uAh;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW:
+		val->intval = di->accum_current_uAh;
+		break;
+	case POWER_SUPPLY_PROP_TEMP:
+		val->intval = di->temp_C;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static enum power_supply_property ds2760_battery_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_EMPTY,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_TEMP,
+};
+
+static int ds2760_battery_probe(struct platform_device *pdev)
+{
+	int retval = 0;
+	struct ds2760_device_info *di;
+	struct ds2760_platform_data *pdata;
+
+	di = kzalloc(sizeof(*di), GFP_KERNEL);
+	if (!di) {
+		retval = -ENOMEM;
+		goto di_alloc_failed;
+	}
+
+	platform_set_drvdata(pdev, di);
+
+	pdata = pdev->dev.platform_data;
+	di->dev		= &pdev->dev;
+	di->w1_dev	     = pdev->dev.parent;
+	di->bat.name	   = pdev->dev.bus_id;
+	di->bat.type	   = POWER_SUPPLY_TYPE_BATTERY;
+	di->bat.properties     = ds2760_battery_props;
+	di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
+	di->bat.get_property   = ds2760_battery_get_property;
+	di->bat.external_power_changed =
+				  ds2760_battery_external_power_changed;
+
+	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
+
+	retval = power_supply_register(&pdev->dev, &di->bat);
+	if (retval) {
+		dev_err(di->dev, "failed to register battery");
+		goto batt_failed;
+	}
+
+	INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
+	di->monitor_wqueue