power_supply: Add MAX17042 Fuel Gauge Driver

The MAX17042 is a fuel gauge with an I2C interface for lithium-ion
betteries. Unlike its predecessor MAX17040, MAX17042 uses 16bit
registers. Besides, MAX17042 has much more features than MAX17040; e.g.,
a thermistor, current and current accumulation measurement, battery
internal resistance estimate, average values of measurement, and others.

This patch implements a driver for MAX17042.
In this initial release, we have implemented the most basic features of
a fuel gauge: measure the battery capacity and voltage.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

3 files changed, 250 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 32165295cb1b..61bf5d724139 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -136,6 +136,16 @@ config BATTERY_MAX17040
           in handheld and portable equipment. The MAX17040 is configured
           to operate with a single lithium cell
 
+config BATTERY_MAX17042
+        tristate "Maxim MAX17042/8997/8966 Fuel Gauge"
+        depends on I2C
+        help
+          MAX17042 is fuel-gauge systems for lithium-ion (Li+) batteries
+          in handheld and portable equipment. The MAX17042 is configured
+          to operate with a single lithium cell. MAX8997 and MAX8966 are
+          multi-function devices that include fuel gauages that are compatible
+          with MAX17042.
+
 config BATTERY_Z2
         tristate "Z2 battery driver"
         depends on I2C && MACH_ZIPIT2
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 545459f9f356..8385bfae8728 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_BATTERY_BQ20Z75)	+= bq20z75.o
 obj-$(CONFIG_BATTERY_BQ27x00)   += bq27x00_battery.o
 obj-$(CONFIG_BATTERY_DA9030)    += da9030_battery.o
 obj-$(CONFIG_BATTERY_MAX17040)  += max17040_battery.o
+obj-$(CONFIG_BATTERY_MAX17042)  += max17042_battery.o
 obj-$(CONFIG_BATTERY_Z2)        += z2_battery.o
 obj-$(CONFIG_BATTERY_S3C_ADC)   += s3c_adc_battery.o
 obj-$(CONFIG_CHARGER_PCF50633)  += pcf50633-charger.o
diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
new file mode 100644
index 000000000000..c5c8805156cb
--- /dev/null
+++ b/drivers/power/max17042_battery.c
@@ -0,0 +1,239 @@
+/*
+ * Fuel gauge driver for Maxim 17042 / 8966 / 8997
+ *  Note that Maxim 8966 and 8997 are mfd and this is its subdevice.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * This driver is based on max17040_battery.c
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/power_supply.h>
+#include <linux/power/max17042_battery.h>
+
+enum max17042_register {
+        MAX17042_STATUS         = 0x00,
+        MAX17042_VALRT_Th       = 0x01,
+        MAX17042_TALRT_Th       = 0x02,
+        MAX17042_SALRT_Th       = 0x03,
+        MAX17042_AtRate         = 0x04,
+        MAX17042_RepCap         = 0x05,
+        MAX17042_RepSOC         = 0x06,
+        MAX17042_Age            = 0x07,
+        MAX17042_TEMP           = 0x08,
+        MAX17042_VCELL          = 0x09,
+        MAX17042_Current        = 0x0A,
+        MAX17042_AvgCurrent     = 0x0B,
+        MAX17042_Qresidual      = 0x0C,
+        MAX17042_SOC            = 0x0D,
+        MAX17042_AvSOC          = 0x0E,
+        MAX17042_RemCap         = 0x0F,
+        MAX17402_FullCAP        = 0x10,
+        MAX17042_TTE            = 0x11,
+        MAX17042_V_empty        = 0x12,
+
+        MAX17042_RSLOW          = 0x14,
+
+        MAX17042_AvgTA          = 0x16,
+        MAX17042_Cycles         = 0x17,
+        MAX17042_DesignCap      = 0x18,
+        MAX17042_AvgVCELL       = 0x19,
+        MAX17042_MinMaxTemp     = 0x1A,
+        MAX17042_MinMaxVolt     = 0x1B,
+        MAX17042_MinMaxCurr     = 0x1C,
+        MAX17042_CONFIG         = 0x1D,
+        MAX17042_ICHGTerm       = 0x1E,
+        MAX17042_AvCap          = 0x1F,
+        MAX17042_ManName        = 0x20,
+        MAX17042_DevName        = 0x21,
+        MAX17042_DevChem        = 0x22,
+
+        MAX17042_TempNom        = 0x24,
+        MAX17042_TempCold       = 0x25,
+        MAX17042_TempHot        = 0x26,
+        MAX17042_AIN            = 0x27,
+        MAX17042_LearnCFG       = 0x28,
+        MAX17042_SHFTCFG        = 0x29,
+        MAX17042_RelaxCFG       = 0x2A,
+        MAX17042_MiscCFG        = 0x2B,
+        MAX17042_TGAIN          = 0x2C,
+        MAx17042_TOFF           = 0x2D,
+        MAX17042_CGAIN          = 0x2E,
+        MAX17042_COFF           = 0x2F,
+
+        MAX17042_Q_empty        = 0x33,
+        MAX17042_T_empty        = 0x34,
+
+        MAX17042_RCOMP0         = 0x38,
+        MAX17042_TempCo         = 0x39,
+        MAX17042_Rx             = 0x3A,
+        MAX17042_T_empty0       = 0x3B,
+        MAX17042_TaskPeriod     = 0x3C,
+        MAX17042_FSTAT          = 0x3D,
+
+        MAX17042_SHDNTIMER      = 0x3F,
+
+        MAX17042_VFRemCap       = 0x4A,
+
+        MAX17042_QH             = 0x4D,
+        MAX17042_QL             = 0x4E,
+};
+
+struct max17042_chip {
+        struct i2c_client *client;
+        struct power_supply battery;
+        struct max17042_platform_data *pdata;
+};
+
+static int max17042_write_reg(struct i2c_client *client, u8 reg, u16 value)
+{
+        int ret = i2c_smbus_write_word_data(client, reg, value);
+
+        if (ret < 0)
+                dev_err(&client->dev, "%s: err %d\n", __func__, ret);
+
+        return ret;
+}
+
+static int max17042_read_reg(struct i2c_client *client, u8 reg)
+{
+        int ret = i2c_smbus_read_word_data(client, reg);
+
+        if (ret < 0)
+                dev_err(&client->dev, "%s: err %d\n", __func__, ret);
+
+        return ret;
+}
+
+static enum power_supply_property max17042_battery_props[] = {
+        POWER_SUPPLY_PROP_VOLTAGE_NOW,
+        POWER_SUPPLY_PROP_VOLTAGE_AVG,
+        POWER_SUPPLY_PROP_CAPACITY,
+};
+
+static int max17042_get_property(struct power_supply *psy,
+                            enum power_supply_property psp,
+                            union power_supply_propval *val)
+{
+        struct max17042_chip *chip = container_of(psy,
+                                struct max17042_chip, battery);
+
+        switch (psp) {
+        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+                val->intval = max17042_read_reg(chip->client,
+                                MAX17042_VCELL) * 83; /* 1000 / 12 = 83 */
+                break;
+        case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+                val->intval = max17042_read_reg(chip->client,
+                                MAX17042_AvgVCELL) * 83;
+                break;
+        case POWER_SUPPLY_PROP_CAPACITY:
+                val->intval = max17042_read_reg(chip->client,
+                                MAX17042_SOC) / 256;
+                break;
+        default:
+                return -EINVAL;
+        }
+        return 0;
+}
+
+static int __devinit max17042_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+        struct max17042_chip *chip;
+        int ret;
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
+                return -EIO;
+
+        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        chip->client = client;
+        chip->pdata = client->dev.platform_data;
+
+        i2c_set_clientdata(client, chip);
+
+        chip->battery.name              = "max17042_battery";
+        chip->battery.type              = POWER_SUPPLY_TYPE_BATTERY;
+        chip->battery.get_property      = max17042_get_property;
+        chip->battery.properties        = max17042_battery_props;
+        chip->battery.num_properties    = ARRAY_SIZE(max17042_battery_props);
+
+        ret = power_supply_register(&client->dev, &chip->battery);
+        if (ret) {
+                dev_err(&client->dev, "failed: power supply register\n");
+                i2c_set_clientdata(client, NULL);
+                kfree(chip);
+                return ret;
+        }
+
+        if (!chip->pdata->enable_current_sense) {
+                max17042_write_reg(client, MAX17042_CGAIN, 0x0000);
+                max17042_write_reg(client, MAX17042_MiscCFG, 0x0003);
+                max17042_write_reg(client, MAX17042_LearnCFG, 0x0007);
+        }
+
+        return 0;
+}
+
+static int __devexit max17042_remove(struct i2c_client *client)
+{
+        struct max17042_chip *chip = i2c_get_clientdata(client);
+
+        power_supply_unregister(&chip->battery);
+        i2c_set_clientdata(client, NULL);
+        kfree(chip);
+        return 0;
+}
+
+static const struct i2c_device_id max17042_id[] = {
+        { "max17042", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, max17042_id);
+
+static struct i2c_driver max17042_i2c_driver = {
+        .driver = {
+                .name   = "max17042",
+        },
+        .probe          = max17042_probe,
+        .remove         = __devexit_p(max17042_remove),
+        .id_table       = max17042_id,
+};
+
+static int __init max17042_init(void)
+{
+        return i2c_add_driver(&max17042_i2c_driver);
+}
+module_init(max17042_init);
+
+static void __exit max17042_exit(void)
+{
+        i2c_del_driver(&max17042_i2c_driver);
+}
+module_exit(max17042_exit);
+
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_DESCRIPTION("MAX17042 Fuel Gauge");
+MODULE_LICENSE("GPL");