w1: add Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC support

Add support for the Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC.

It was suggested to combine this functionality with the current ds2782
driver.  Unfortunately, I'm unable to commit the time to refactoring this
driver to that extent and I don't have a platform with the ds2782 part to
validate that there are no regression issues by adding this functionality.

[akpm@linux-foundation.org: use min_t()]
Signed-off-by: Clifton Barnes <cabarnes@indesign-llc.com>
Tested-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 861 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 52a462fc6b84..dc8c531ed276 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -68,6 +68,13 @@ config BATTERY_DS2760
         help
           Say Y here to enable support for batteries with ds2760 chip.
 
+config BATTERY_DS2780
+        tristate "DS2780 battery driver"
+        select W1
+        select W1_SLAVE_DS2780
+        help
+          Say Y here to enable support for batteries with ds2780 chip.
+
 config BATTERY_DS2782
         tristate "DS2782/DS2786 standalone gas-gauge"
         depends on I2C
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 8385bfae8728..8224990b933d 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_WM8350_POWER)	+= wm8350_power.o
 obj-$(CONFIG_TEST_POWER)        += test_power.o
 
 obj-$(CONFIG_BATTERY_DS2760)    += ds2760_battery.o
+obj-$(CONFIG_BATTERY_DS2780)    += ds2780_battery.o
 obj-$(CONFIG_BATTERY_DS2782)    += ds2782_battery.o
 obj-$(CONFIG_BATTERY_PMU)       += pmu_battery.o
 obj-$(CONFIG_BATTERY_OLPC)      += olpc_battery.o
diff --git a/drivers/power/ds2780_battery.c b/drivers/power/ds2780_battery.c
new file mode 100644
index 000000000000..1fefe82e12e3
--- /dev/null
+++ b/drivers/power/ds2780_battery.c
@@ -0,0 +1,853 @@
+/*
+ * 1-wire client/driver for the Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC
+ *
+ * Copyright (C) 2010 Indesign, LLC
+ *
+ * Author: Clifton Barnes <cabarnes@indesign-llc.com>
+ *
+ * Based on ds2760_battery and ds2782_battery drivers
+ *
+ * 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/slab.h>
+#include <linux/param.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/idr.h>
+
+#include "../w1/w1.h"
+#include "../w1/slaves/w1_ds2780.h"
+
+/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
+#define DS2780_CURRENT_UNITS    1563
+/* Charge unit measurement in uAh for a 1 milli-ohm sense resistor */
+#define DS2780_CHARGE_UNITS             6250
+/* Number of bytes in user EEPROM space */
+#define DS2780_USER_EEPROM_SIZE         (DS2780_EEPROM_BLOCK0_END - \
+                                        DS2780_EEPROM_BLOCK0_START + 1)
+/* Number of bytes in parameter EEPROM space */
+#define DS2780_PARAM_EEPROM_SIZE        (DS2780_EEPROM_BLOCK1_END - \
+                                        DS2780_EEPROM_BLOCK1_START + 1)
+
+struct ds2780_device_info {
+        struct device *dev;
+        struct power_supply bat;
+        struct device *w1_dev;
+};
+
+enum current_types {
+        CURRENT_NOW,
+        CURRENT_AVG,
+};
+
+static const char model[] = "DS2780";
+static const char manufacturer[] = "Maxim/Dallas";
+
+static inline struct ds2780_device_info *to_ds2780_device_info(
+        struct power_supply *psy)
+{
+        return container_of(psy, struct ds2780_device_info, bat);
+}
+
+static inline struct power_supply *to_power_supply(struct device *dev)
+{
+        return dev_get_drvdata(dev);
+}
+
+static inline int ds2780_read8(struct device *dev, u8 *val, int addr)
+{
+        return w1_ds2780_io(dev, val, addr, sizeof(u8), 0);
+}
+
+static int ds2780_read16(struct device *dev, s16 *val, int addr)
+{
+        int ret;
+        u8 raw[2];
+
+        ret = w1_ds2780_io(dev, raw, addr, sizeof(u8) * 2, 0);
+        if (ret < 0)
+                return ret;
+
+        *val = (raw[0] << 8) | raw[1];
+
+        return 0;
+}
+
+static inline int ds2780_read_block(struct device *dev, u8 *val, int addr,
+        size_t count)
+{
+        return w1_ds2780_io(dev, val, addr, count, 0);
+}
+
+static inline int ds2780_write(struct device *dev, u8 *val, int addr,
+        size_t count)
+{
+        return w1_ds2780_io(dev, val, addr, count, 1);
+}
+
+static inline int ds2780_store_eeprom(struct device *dev, int addr)
+{
+        return w1_ds2780_eeprom_cmd(dev, addr, W1_DS2780_COPY_DATA);
+}
+
+static inline int ds2780_recall_eeprom(struct device *dev, int addr)
+{
+        return w1_ds2780_eeprom_cmd(dev, addr, W1_DS2780_RECALL_DATA);
+}
+
+static int ds2780_save_eeprom(struct ds2780_device_info *dev_info, int reg)
+{
+        int ret;
+
+        ret = ds2780_store_eeprom(dev_info->w1_dev, reg);
+        if (ret < 0)
+                return ret;
+
+        ret = ds2780_recall_eeprom(dev_info->w1_dev, reg);
+        if (ret < 0)
+                return ret;
+
+        return 0;
+}
+
+/* Set sense resistor value in mhos */
+static int ds2780_set_sense_register(struct ds2780_device_info *dev_info,
+        u8 conductance)
+{
+        int ret;
+
+        ret = ds2780_write(dev_info->w1_dev, &conductance,
+                                DS2780_RSNSP_REG, sizeof(u8));
+        if (ret < 0)
+                return ret;
+
+        return ds2780_save_eeprom(dev_info, DS2780_RSNSP_REG);
+}
+
+/* Get RSGAIN value from 0 to 1.999 in steps of 0.001 */
+static int ds2780_get_rsgain_register(struct ds2780_device_info *dev_info,
+        u16 *rsgain)
+{
+        return ds2780_read16(dev_info->w1_dev, rsgain, DS2780_RSGAIN_MSB_REG);
+}
+
+/* Set RSGAIN value from 0 to 1.999 in steps of 0.001 */
+static int ds2780_set_rsgain_register(struct ds2780_device_info *dev_info,
+        u16 rsgain)
+{
+        int ret;
+        u8 raw[] = {rsgain >> 8, rsgain & 0xFF};
+
+        ret = ds2780_write(dev_info->w1_dev, raw,
+                                DS2780_RSGAIN_MSB_REG, sizeof(u8) * 2);
+        if (ret < 0)
+                return ret;
+
+        return ds2780_save_eeprom(dev_info, DS2780_RSGAIN_MSB_REG);
+}
+
+static int ds2780_get_voltage(struct ds2780_device_info *dev_info,
+        int *voltage_uV)
+{
+        int ret;
+        s16 voltage_raw;
+
+        /*
+         * The voltage value is located in 10 bits across the voltage MSB
+         * and LSB registers in two's compliment form
+         * Sign bit of the voltage value is in bit 7 of the voltage MSB register
+         * Bits 9 - 3 of the voltage value are in bits 6 - 0 of the
+         * voltage MSB register
+         * Bits 2 - 0 of the voltage value are in bits 7 - 5 of the
+         * voltage LSB register
+         */
+        ret = ds2780_read16(dev_info->w1_dev, &voltage_raw,
+                                DS2780_VOLT_MSB_REG);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * DS2780 reports voltage in units of 4.88mV, but the battery class
+         * reports in units of uV, so convert by multiplying by 4880.
+         */
+        *voltage_uV = (voltage_raw / 32) * 4880;
+        return 0;
+}
+
+static int ds2780_get_temperature(struct ds2780_device_info *dev_info,
+        int *temperature)
+{
+        int ret;
+        s16 temperature_raw;
+
+        /*
+         * The temperature value is located in 10 bits across the temperature
+         * MSB and LSB registers in two's compliment form
+         * Sign bit of the temperature value is in bit 7 of the temperature
+         * MSB register
+         * Bits 9 - 3 of the temperature value are in bits 6 - 0 of the
+         * temperature MSB register
+         * Bits 2 - 0 of the temperature value are in bits 7 - 5 of the
+         * temperature LSB register
+         */
+        ret = ds2780_read16(dev_info->w1_dev, &temperature_raw,
+                                DS2780_TEMP_MSB_REG);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * Temperature is measured in units of 0.125 degrees celcius, the
+         * power_supply class measures temperature in tenths of degrees
+         * celsius. The temperature value is stored as a 10 bit number, plus
+         * sign in the upper bits of a 16 bit register.
+         */
+        *temperature = ((temperature_raw / 32) * 125) / 100;
+        return 0;
+}
+
+static int ds2780_get_current(struct ds2780_device_info *dev_info,
+        enum current_types type, int *current_uA)
+{
+        int ret, sense_res;
+        s16 current_raw;
+        u8 sense_res_raw, reg_msb;
+
+        /*
+         * The units of measurement for current are dependent on the value of
+         * the sense resistor.
+         */
+        ret = ds2780_read8(dev_info->w1_dev, &sense_res_raw, DS2780_RSNSP_REG);
+        if (ret < 0)
+                return ret;
+
+        if (sense_res_raw == 0) {
+                dev_err(dev_info->dev, "sense resistor value is 0\n");
+                return -ENXIO;
+        }
+        sense_res = 1000 / sense_res_raw;
+
+        if (type == CURRENT_NOW)
+                reg_msb = DS2780_CURRENT_MSB_REG;
+        else if (type == CURRENT_AVG)
+                reg_msb = DS2780_IAVG_MSB_REG;
+        else
+                return -EINVAL;
+
+        /*
+         * The current value is located in 16 bits across the current MSB
+         * and LSB registers in two's compliment form
+         * Sign bit of the current value is in bit 7 of the current MSB register
+         * Bits 14 - 8 of the current value are in bits 6 - 0 of the current
+         * MSB register
+         * Bits 7 - 0 of the current value are in bits 7 - 0 of the current
+         * LSB register
+         */
+        ret = ds2780_read16(dev_info->w1_dev, &current_raw, reg_msb);
+        if (ret < 0)
+                return ret;
+
+        *current_uA = current_raw * (DS2780_CURRENT_UNITS / sense_res);
+        return 0;
+}
+
+static int ds2780_get_accumulated_current(struct ds2780_device_info *dev_info,
+        int *accumulated_current)
+{
+        int ret, sense_res;
+        s16 current_raw;
+        u8 sense_res_raw;
+
+        /*
+         * The units of measurement for accumulated current are dependent on
+         * the value of the sense resistor.
+         */
+        ret = ds2780_read8(dev_info->w1_dev, &sense_res_raw, DS2780_RSNSP_REG);
+        if (ret < 0)
+                return ret;
+
+        if (sense_res_raw == 0) {
+                dev_err(dev_info->dev, "sense resistor value is 0\n");
+                return -ENXIO;
+        }
+        sense_res = 1000 / sense_res_raw;
+
+        /*
+         * The ACR value is located in 16 bits across the ACR MSB and
+         * LSB registers
+         * Bits 15 - 8 of the ACR value are in bits 7 - 0 of the ACR
+         * MSB register
+         * Bits 7 - 0 of the ACR value are in bits 7 - 0 of the ACR
+         * LSB register
+         */
+        ret = ds2780_read16(dev_info->w1_dev, &current_raw, DS2780_ACR_MSB_REG);
+        if (ret < 0)
+                return ret;
+
+        *accumulated_current = current_raw * (DS2780_CHARGE_UNITS / sense_res);
+        return 0;
+}
+
+static int ds2780_get_capacity(struct ds2780_device_info *dev_info,
+        int *capacity)
+{
+        int ret;
+        u8 raw;
+
+        ret = ds2780_read8(dev_info->w1_dev, &raw, DS2780_RARC_REG);
+        if (ret < 0)
+                return ret;
+
+        *capacity = raw;
+        return raw;
+}
+
+static int ds2780_get_status(struct ds2780_device_info *dev_info, int *status)
+{
+        int ret, current_uA, capacity;
+
+        ret = ds2780_get_current(dev_info, CURRENT_NOW, &current_uA);
+        if (ret < 0)
+                return ret;
+
+        ret = ds2780_get_capacity(dev_info, &capacity);
+        if (ret < 0)
+                return ret;
+
+        if (capacity == 100)
+                *status = POWER_SUPPLY_STATUS_FULL;
+        else if (current_uA == 0)
+                *status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+        else if (current_uA < 0)
+                *status = POWER_SUPPLY_STATUS_DISCHARGING;
+        else
+                *status = POWER_SUPPLY_STATUS_CHARGING;
+
+        return 0;
+}
+
+static int ds2780_get_charge_now(struct ds2780_device_info *dev_info,
+        int *charge_now)
+{
+        int ret;
+        u16 charge_raw;
+
+        /*
+         * The RAAC value is located in 16 bits across the RAAC MSB and
+         * LSB registers
+         * Bits 15 - 8 of the RAAC value are in bits 7 - 0 of the RAAC
+         * MSB register
+         * Bits 7 - 0 of the RAAC value are in bits 7 - 0 of the RAAC
+         * LSB register
+         */
+        ret = ds2780_read16(dev_info->w1_dev, &charge_raw, DS2780_RAAC_MSB_REG);
+        if (ret < 0)
+                return ret;
+
+        *charge_now = charge_raw * 1600;
+        return 0;
+}
+
+static int ds2780_get_control_register(struct ds2780_device_info *dev_info,
+        u8 *control_reg)
+{
+        return ds2780_read8(dev_info->w1_dev, control_reg, DS2780_CONTROL_REG);
+}
+
+static int ds2780_set_control_register(struct ds2780_device_info *dev_info,
+        u8 control_reg)
+{
+        int ret;
+
+        ret = ds2780_write(dev_info->w1_dev, &control_reg,
+                                DS2780_CONTROL_REG, sizeof(u8));
+        if (ret < 0)
+                return ret;
+
+        return ds2780_save_eeprom(dev_info, DS2780_CONTROL_REG);
+}
+
+static int ds2780_battery_get_property(struct power_supply *psy,
+        enum power_supply_property psp,
+        union power_supply_propval *val)
+{
+        int ret = 0;
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+                ret = ds2780_get_voltage(dev_info, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_TEMP:
+                ret = ds2780_get_temperature(dev_info, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_MODEL_NAME:
+                val->strval = model;
+                break;
+
+        case POWER_SUPPLY_PROP_MANUFACTURER:
+                val->strval = manufacturer;
+                break;
+
+        case POWER_SUPPLY_PROP_CURRENT_NOW:
+                ret = ds2780_get_current(dev_info, CURRENT_NOW, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_CURRENT_AVG:
+                ret = ds2780_get_current(dev_info, CURRENT_AVG, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_STATUS:
+                ret = ds2780_get_status(dev_info, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_CAPACITY:
+                ret = ds2780_get_capacity(dev_info, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_CHARGE_COUNTER:
+                ret = ds2780_get_accumulated_current(dev_info, &val->intval);
+                break;
+
+        case POWER_SUPPLY_PROP_CHARGE_NOW:
+                ret = ds2780_get_charge_now(dev_info, &val->intval);
+                break;
+
+        default:
+                ret = -EINVAL;
+        }
+
+        return ret;
+}
+
+static enum power_supply_property ds2780_battery_props[] = {
+        POWER_SUPPLY_PROP_STATUS,
+        POWER_SUPPLY_PROP_VOLTAGE_NOW,
+        POWER_SUPPLY_PROP_TEMP,
+        POWER_SUPPLY_PROP_MODEL_NAME,
+        POWER_SUPPLY_PROP_MANUFACTURER,
+        POWER_SUPPLY_PROP_CURRENT_NOW,
+        POWER_SUPPLY_PROP_CURRENT_AVG,
+        POWER_SUPPLY_PROP_CAPACITY,
+        POWER_SUPPLY_PROP_CHARGE_COUNTER,
+        POWER_SUPPLY_PROP_CHARGE_NOW,
+};
+
+static ssize_t ds2780_get_pmod_enabled(struct device *dev,
+        struct device_attribute *attr,
+        char *buf)
+{
+        int ret;
+        u8 control_reg;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        /* Get power mode */
+        ret = ds2780_get_control_register(dev_info, &control_reg);
+        if (ret < 0)
+                return ret;
+
+        return sprintf(buf, "%d\n",
+                 !!(control_reg & DS2780_CONTROL_REG_PMOD));
+}
+
+static ssize_t ds2780_set_pmod_enabled(struct device *dev,
+        struct device_attribute *attr,
+        const char *buf,
+        size_t count)
+{
+        int ret;
+        u8 control_reg, new_setting;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        /* Set power mode */
+        ret = ds2780_get_control_register(dev_info, &control_reg);
+        if (ret < 0)
+                return ret;
+
+        ret = kstrtou8(buf, 0, &new_setting);
+        if (ret < 0)
+                return ret;
+
+        if ((new_setting != 0) && (new_setting != 1)) {
+                dev_err(dev_info->dev, "Invalid pmod setting (0 or 1)\n");
+                return -EINVAL;
+        }
+
+        if (new_setting)
+                control_reg |= DS2780_CONTROL_REG_PMOD;
+        else
+                control_reg &= ~DS2780_CONTROL_REG_PMOD;
+
+        ret = ds2780_set_control_register(dev_info, control_reg);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static ssize_t ds2780_get_sense_resistor_value(struct device *dev,
+        struct device_attribute *attr,
+        char *buf)
+{
+        int ret;
+        u8 sense_resistor;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = ds2780_read8(dev_info->w1_dev, &sense_resistor, DS2780_RSNSP_REG);
+        if (ret < 0)
+                return ret;
+
+        ret = sprintf(buf, "%d\n", sense_resistor);
+        return ret;
+}
+
+static ssize_t ds2780_set_sense_resistor_value(struct device *dev,
+        struct device_attribute *attr,
+        const char *buf,
+        size_t count)
+{
+        int ret;
+        u8 new_setting;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = kstrtou8(buf, 0, &new_setting);
+        if (ret < 0)
+                return ret;
+
+        ret = ds2780_set_sense_register(dev_info, new_setting);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static ssize_t ds2780_get_rsgain_setting(struct device *dev,
+        struct device_attribute *attr,
+        char *buf)
+{
+        int ret;
+        u16 rsgain;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = ds2780_get_rsgain_register(dev_info, &rsgain);
+        if (ret < 0)
+                return ret;
+
+        return sprintf(buf, "%d\n", rsgain);
+}
+
+static ssize_t ds2780_set_rsgain_setting(struct device *dev,
+        struct device_attribute *attr,
+        const char *buf,
+        size_t count)
+{
+        int ret;
+        u16 new_setting;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = kstrtou16(buf, 0, &new_setting);
+        if (ret < 0)
+                return ret;
+
+        /* Gain can only be from 0 to 1.999 in steps of .001 */
+        if (new_setting > 1999) {
+                dev_err(dev_info->dev, "Invalid rsgain setting (0 - 1999)\n");
+                return -EINVAL;
+        }
+
+        ret = ds2780_set_rsgain_register(dev_info, new_setting);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static ssize_t ds2780_get_pio_pin(struct device *dev,
+        struct device_attribute *attr,
+        char *buf)
+{
+        int ret;
+        u8 sfr;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = ds2780_read8(dev_info->w1_dev, &sfr, DS2780_SFR_REG);
+        if (ret < 0)
+                return ret;
+
+        ret = sprintf(buf, "%d\n", sfr & DS2780_SFR_REG_PIOSC);
+        return ret;
+}
+
+static ssize_t ds2780_set_pio_pin(struct device *dev,
+        struct device_attribute *attr,
+        const char *buf,
+        size_t count)
+{
+        int ret;
+        u8 new_setting;
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        ret = kstrtou8(buf, 0, &new_setting);
+        if (ret < 0)
+                return ret;
+
+        if ((new_setting != 0) && (new_setting != 1)) {
+                dev_err(dev_info->dev, "Invalid pio_pin setting (0 or 1)\n");
+                return -EINVAL;
+        }
+
+        ret = ds2780_write(dev_info->w1_dev, &new_setting,
+                                DS2780_SFR_REG, sizeof(u8));
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static ssize_t ds2780_read_param_eeprom_bin(struct file *filp,
+                                struct kobject *kobj,
+                                struct bin_attribute *bin_attr,
+                                char *buf, loff_t off, size_t count)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        count = min_t(loff_t, count,
+                DS2780_EEPROM_BLOCK1_END -
+                DS2780_EEPROM_BLOCK1_START + 1 - off);
+
+        return ds2780_read_block(dev_info->w1_dev, buf,
+                                DS2780_EEPROM_BLOCK1_START + off, count);
+}
+
+static ssize_t ds2780_write_param_eeprom_bin(struct file *filp,
+                                struct kobject *kobj,
+                                struct bin_attribute *bin_attr,
+                                char *buf, loff_t off, size_t count)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+        int ret;
+
+        count = min_t(loff_t, count,
+                DS2780_EEPROM_BLOCK1_END -
+                DS2780_EEPROM_BLOCK1_START + 1 - off);
+
+        ret = ds2780_write(dev_info->w1_dev, buf,
+                                DS2780_EEPROM_BLOCK1_START + off, count);
+        if (ret < 0)
+                return ret;
+
+        ret = ds2780_save_eeprom(dev_info, DS2780_EEPROM_BLOCK1_START);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static struct bin_attribute ds2780_param_eeprom_bin_attr = {
+        .attr = {
+                .name = "param_eeprom",
+                .mode = S_IRUGO | S_IWUSR,
+        },
+        .size = DS2780_EEPROM_BLOCK1_END - DS2780_EEPROM_BLOCK1_START + 1,
+        .read = ds2780_read_param_eeprom_bin,
+        .write = ds2780_write_param_eeprom_bin,
+};
+
+static ssize_t ds2780_read_user_eeprom_bin(struct file *filp,
+                                struct kobject *kobj,
+                                struct bin_attribute *bin_attr,
+                                char *buf, loff_t off, size_t count)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+
+        count = min_t(loff_t, count,
+                DS2780_EEPROM_BLOCK0_END -
+                DS2780_EEPROM_BLOCK0_START + 1 - off);
+
+        return ds2780_read_block(dev_info->w1_dev, buf,
+                                DS2780_EEPROM_BLOCK0_START + off, count);
+
+}
+
+static ssize_t ds2780_write_user_eeprom_bin(struct file *filp,
+                                struct kobject *kobj,
+                                struct bin_attribute *bin_attr,
+                                char *buf, loff_t off, size_t count)
+{
+        struct device *dev = container_of(kobj, struct device, kobj);
+        struct power_supply *psy = to_power_supply(dev);
+        struct ds2780_device_info *dev_info = to_ds2780_device_info(psy);
+        int ret;
+
+        count = min_t(loff_t, count,
+                DS2780_EEPROM_BLOCK0_END -
+                DS2780_EEPROM_BLOCK0_START + 1 - off);
+
+        ret = ds2780_write(dev_info->w1_dev, buf,
+                                DS2780_EEPROM_BLOCK0_START + off, count);
+        if (ret < 0)
+                return ret;
+
+        ret = ds2780_save_eeprom(dev_info, DS2780_EEPROM_BLOCK0_START);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static struct bin_attribute ds2780_user_eeprom_bin_attr = {
+        .attr = {
+                .name = "user_eeprom",
+                .mode = S_IRUGO | S_IWUSR,
+        },
+        .size = DS2780_EEPROM_BLOCK0_END - DS2780_EEPROM_BLOCK0_START + 1,
+        .read = ds2780_read_user_eeprom_bin,
+        .write = ds2780_write_user_eeprom_bin,
+};
+
+static DEVICE_ATTR(pmod_enabled, S_IRUGO | S_IWUSR, ds2780_get_pmod_enabled,
+        ds2780_set_pmod_enabled);
+static DEVICE_ATTR(sense_resistor_value, S_IRUGO | S_IWUSR,
+        ds2780_get_sense_resistor_value, ds2780_set_sense_resistor_value);
+static DEVICE_ATTR(rsgain_setting, S_IRUGO | S_IWUSR, ds2780_get_rsgain_setting,
+        ds2780_set_rsgain_setting);
+static DEVICE_ATTR(pio_pin, S_IRUGO | S_IWUSR, ds2780_get_pio_pin,
+        ds2780_set_pio_pin);
+
+
+static struct attribute *ds2780_attributes[] = {
+        &dev_attr_pmod_enabled.attr,
+        &dev_attr_sense_resistor_value.attr,
+        &dev_attr_rsgain_setting.attr,
+        &dev_attr_pio_pin.attr,
+        NULL
+};
+
+static const struct attribute_group ds2780_attr_group = {
+        .attrs = ds2780_attributes,
+};
+
+static int __devinit ds2780_battery_probe(struct platform_device *pdev)
+{
+        int ret = 0;
+        struct ds2780_device_info *dev_info;
+
+        dev_info = kzalloc(sizeof(*dev_info), GFP_KERNEL);
+        if (!dev_info) {
+                ret = -ENOMEM;
+                goto fail;
+        }
+
+        platform_set_drvdata(pdev, dev_info);
+
+        dev_info->dev                   = &pdev->dev;
+        dev_info->w1_dev                = pdev->dev.parent;
+        dev_info->bat.name              = dev_name(&pdev->dev);
+        dev_info->bat.type              = POWER_SUPPLY_TYPE_BATTERY;
+        dev_info->bat.properties        = ds2780_battery_props;
+        dev_info->bat.num_properties    = ARRAY_SIZE(ds2780_battery_props);
+        dev_info->bat.get_property      = ds2780_battery_get_property;
+
+        ret = power_supply_register(&pdev->dev, &dev_info->bat);
+        if (ret) {
+                dev_err(dev_info->dev, "failed to register battery\n");
+                goto fail_free_info;
+        }
+
+        ret = sysfs_create_group(&dev_info->bat.dev->kobj, &ds2780_attr_group);
+        if (ret) {
+                dev_err(dev_info->dev, "failed to create sysfs group\n");
+                goto fail_unregister;
+        }
+
+        ret = sysfs_create_bin_file(&dev_info->bat.dev->kobj,
+                                        &ds2780_param_eeprom_bin_attr);
+        if (ret) {
+                dev_err(dev_info->dev,
+                                "failed to create param eeprom bin file");
+                goto fail_remove_group;
+        }
+
+        ret = sysfs_create_bin_file(&dev_info->bat.dev->kobj,
+                                        &ds2780_user_eeprom_bin_attr);
+        if (ret) {
+                dev_err(dev_info->dev,
+                                "failed to create user eeprom bin file");
+                goto fail_remove_bin_file;
+        }
+
+        return 0;
+
+fail_remove_bin_file:
+        sysfs_remove_bin_file(&dev_info->bat.dev->kobj,
+                                &ds2780_param_eeprom_bin_attr);
+fail_remove_group:
+        sysfs_remove_group(&dev_info->bat.dev->kobj, &ds2780_attr_group);
+fail_unregister:
+        power_supply_unregister(&dev_info->bat);
+fail_free_info:
+        kfree(dev_info);
+fail:
+        return ret;
+}
+
+static int __devexit ds2780_battery_remove(struct platform_device *pdev)
+{
+        struct ds2780_device_info *dev_info = platform_get_drvdata(pdev);
+
+        /* remove attributes */
+        sysfs_remove_group(&dev_info->bat.dev->kobj, &ds2780_attr_group);
+
+        power_supply_unregister(&dev_info->bat);
+
+        kfree(dev_info);
+        return 0;
+}
+
+MODULE_ALIAS("platform:ds2780-battery");
+
+static struct platform_driver ds2780_battery_driver = {
+        .driver = {
+                .name = "ds2780-battery",
+        },
+        .probe    = ds2780_battery_probe,
+        .remove   = ds2780_battery_remove,
+};
+
+static int __init ds2780_battery_init(void)
+{
+        return platform_driver_register(&ds2780_battery_driver);
+}
+
+static void __exit ds2780_battery_exit(void)
+{
+        platform_driver_unregister(&ds2780_battery_driver);
+}
+
+module_init(ds2780_battery_init);
+module_exit(ds2780_battery_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
+MODULE_DESCRIPTION("Maxim/Dallas DS2780 Stand-Alone Fuel Gauage IC driver");