Maxim Semiconductor MAX17211/MAX17215 single/multi-cell fuel gauge
monitor with M5 Fuel Gauge algorithm

This driver provide userspace access to MAX17211/MAX17215 data with
power_supply class drivers.
---
 drivers/power/supply/Kconfig            |   8 +
 drivers/power/supply/Makefile           |   1 +
 drivers/power/supply/max1721x_battery.c | 303 ++++++++++++++++++++++++++++++++
 3 files changed, 312 insertions(+)
 create mode 100644 drivers/power/supply/max1721x_battery.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 76806a0..25fe441 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -117,6 +117,14 @@ config BATTERY_DS2782
          Say Y here to enable support for the DS2782/DS2786 standalone battery
          gas-gauge.
 
+config BATTERY_MAX1721X
+       tristate "MAX17211/MAX17215 standalone gas-gauge"
+       depends on W1
+       select W1_SLAVE_MAX1721X
+       help
+         Say Y here to enable support for the MAX17211/MAX17215 standalone
+         battery gas-gauge.
+
 config BATTERY_PMU
        tristate "Apple PMU battery"
        depends on PPC32 && ADB_PMU
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 36c599d..1e5546d 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_BATTERY_DS2760)  += ds2760_battery.o
 obj-$(CONFIG_BATTERY_DS2780)   += ds2780_battery.o
 obj-$(CONFIG_BATTERY_DS2781)   += ds2781_battery.o
 obj-$(CONFIG_BATTERY_DS2782)   += ds2782_battery.o
+obj-$(CONFIG_BATTERY_MAX1721X) += max1721x_battery.o
 obj-$(CONFIG_BATTERY_GAUGE_LTC2941)    += ltc2941-battery-gauge.o
 obj-$(CONFIG_BATTERY_GOLDFISH) += goldfish_battery.o
 obj-$(CONFIG_BATTERY_PMU)      += pmu_battery.o
diff --git a/drivers/power/supply/max1721x_battery.c 
b/drivers/power/supply/max1721x_battery.c
new file mode 100644
index 0000000..ff77d3f
--- /dev/null
+++ b/drivers/power/supply/max1721x_battery.c
@@ -0,0 +1,303 @@
+/*
+ * 1-wire client/driver for the Maxim MAX17211/MAX17215 Fuel Gauge IC
+ *
+ * Author: Alex A. Mihaylov <minimum...@rambler.ru>
+ *
+ * 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_max1721x.h"
+
+#define DEF_DEV_NAME_MAX17211  "MAX17211"
+#define DEF_DEV_NAME_MAX17215  "MAX17215"
+#define DEF_DEV_NAME_UNKNOWN   "UNKNOWN"
+#define DEF_MFG_NAME           "MAXIM"
+
+struct max17211_device_info {
+       struct device *dev;
+       struct power_supply *bat;
+       struct power_supply_desc bat_desc;
+       struct device *w1_dev;
+       /* battery design format */
+       uint16_t rsense; /* in tenths uOhm */
+       char DeviceName[2 * MAX1721X_REG_DEV_NUMB + 1];
+       char ManufacturerName[2 * MAX1721X_REG_MFG_NUMB + 1];
+       char SerialNumber[13]; /* see get_sn_str() later for comment */
+};
+
+static inline struct max17211_device_info *
+to_device_info(struct power_supply *psy)
+{
+       return power_supply_get_drvdata(psy);
+}
+
+static int max1721x_battery_get_property(struct power_supply *psy,
+       enum power_supply_property psp,
+       union power_supply_propval *val)
+{
+       struct max17211_device_info *info = to_device_info(psy);
+       uint16_t reg;
+       int ret = 0;
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_PRESENT:
+               /*
+                * POWER_SUPPLY_PROP_PRESENT will always readable via
+                * sysfs interface. Value return 0 if battery not
+                * present or unaccesable via W1.
+                */
+               val->intval =
+                       w1_max1721x_reg_get(info->w1_dev, MAX172XX_REG_STATUS,
+                               &reg) ? 0 : !(reg & MAX172XX_BAT_PRESENT);
+               break;
+       case POWER_SUPPLY_PROP_CAPACITY:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_REPSOC, &reg);
+               val->intval = max172xx_percent_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_BATT, &reg);
+               val->intval = max172xx_voltage_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_DESIGNCAP, &reg);
+               val->intval = max172xx_capacity_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_CHARGE_AVG:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_REPCAP, &reg);
+               val->intval = max172xx_capacity_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_TTE, &reg);
+               val->intval = max172xx_time_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_TTF, &reg);
+               val->intval = max172xx_time_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_TEMP:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_TEMP, &reg);
+               val->intval = max172xx_temperature_to_ps(reg);
+               break;
+       case POWER_SUPPLY_PROP_CURRENT_NOW:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_CURRENT, &reg);
+               val->intval = max172xx_current_to_voltage(reg) / info->rsense;
+               break;
+       case POWER_SUPPLY_PROP_CURRENT_AVG:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX172XX_REG_AVGCURRENT, &reg);
+               val->intval = max172xx_current_to_voltage(reg) / info->rsense;
+               break;
+       /*
+        * Strings already received and inited by probe.
+        * We do dummy read for check battery still available.
+        */
+       case POWER_SUPPLY_PROP_MODEL_NAME:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX1721X_REG_DEV_STR, &reg);
+               val->strval = info->DeviceName;
+               break;
+       case POWER_SUPPLY_PROP_MANUFACTURER:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX1721X_REG_MFG_STR, &reg);
+               val->strval = info->ManufacturerName;
+               break;
+       case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+               ret = w1_max1721x_reg_get(info->w1_dev,
+                       MAX1721X_REG_SER_HEX, &reg);
+               val->strval = info->SerialNumber;
+               break;
+       default:
+               ret = -EINVAL;
+       }
+
+       return ret;
+}
+
+static enum power_supply_property max1721x_battery_props[] = {
+       /* int */
+       POWER_SUPPLY_PROP_PRESENT,
+       POWER_SUPPLY_PROP_CAPACITY,
+       POWER_SUPPLY_PROP_VOLTAGE_NOW,
+       POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+       POWER_SUPPLY_PROP_CHARGE_AVG,
+       POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
+       POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
+       POWER_SUPPLY_PROP_TEMP,
+       POWER_SUPPLY_PROP_CURRENT_NOW,
+       POWER_SUPPLY_PROP_CURRENT_AVG,
+       /* strings */
+       POWER_SUPPLY_PROP_MODEL_NAME,
+       POWER_SUPPLY_PROP_MANUFACTURER,
+       POWER_SUPPLY_PROP_SERIAL_NUMBER,
+};
+
+static int get_string(struct device *dev, uint16_t reg, uint8_t nr, char *str)
+{
+       uint16_t val;
+
+       if (!str || !(reg == MAX1721X_REG_MFG_STR ||
+                       reg == MAX1721X_REG_DEV_STR))
+               return -EFAULT;
+
+       while (nr--) {
+               if (w1_max1721x_reg_get(dev, reg++, &val))
+                       return -EFAULT;
+               *str++ = val>>8 & 0x00FF;
+               *str++ = val & 0x00FF;
+       }
+       return 0;
+}
+
+/* Maxim say: Serial number is a hex string up to 12 hex characters */
+static int get_sn_string(struct device *dev, char *str)
+{
+       uint16_t val[3];
+
+       if (!str)
+               return -EFAULT;
+
+       if (w1_max1721x_reg_get(dev, MAX1721X_REG_SER_HEX, &val[0]))
+               return -EFAULT;
+       if (w1_max1721x_reg_get(dev, MAX1721X_REG_SER_HEX + 1, &val[1]))
+               return -EFAULT;
+       if (w1_max1721x_reg_get(dev, MAX1721X_REG_SER_HEX + 2, &val[2]))
+               return -EFAULT;
+
+       snprintf(str, 13, "%04X%04X%04X", val[0], val[1], val[2]);
+       return 0;
+}
+
+static int max1721x_battery_probe(struct platform_device *pdev)
+{
+       struct power_supply_config psy_cfg = {};
+       struct max17211_device_info *info;
+
+       info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, info);
+
+       info->dev = &pdev->dev;
+       info->w1_dev = pdev->dev.parent;
+       info->bat_desc.name = dev_name(&pdev->dev);
+       info->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+       info->bat_desc.properties = max1721x_battery_props;
+       info->bat_desc.num_properties = ARRAY_SIZE(max1721x_battery_props);
+       info->bat_desc.get_property = max1721x_battery_get_property;
+       /*
+        * FixMe:
+        * Device without no_thermal = true not register (err -22)
+        * Len of platform device name "max17211-battery.X.auto"
+        * more than 20 chars limit in THERMAL_NAME_LENGTH from
+        * include/uapi/linux/thermal.h
+        */
+       info->bat_desc.no_thermal = true;
+       psy_cfg.drv_data = info;
+
+       if (w1_max1721x_reg_get(info->w1_dev,
+                       MAX1721X_REG_NRSENSE, &info->rsense))
+               return -ENODEV;
+
+       if (!info->rsense) {
+               dev_warn(info->dev, "RSenese not calibrated, set 10 mOhms!\n");
+               info->rsense = 1000; /* in regs in 10^-5 */
+       }
+       dev_dbg(info->dev, "RSense: %d mOhms.\n", info->rsense / 100);
+
+       if (get_string(info->w1_dev, MAX1721X_REG_MFG_STR,
+                       MAX1721X_REG_MFG_NUMB, info->ManufacturerName)) {
+               dev_err(info->dev, "Can't read manufacturer. Hardware 
error.\n");
+               return -ENODEV;
+       }
+
+       if (!info->ManufacturerName[0])
+               strncpy(info->ManufacturerName, DEF_MFG_NAME,
+                       2 * MAX1721X_REG_MFG_NUMB);
+
+       if (get_string(info->w1_dev, MAX1721X_REG_DEV_STR,
+                       MAX1721X_REG_DEV_NUMB, info->DeviceName)) {
+               dev_err(info->dev, "Can't read device. Hardware error.\n");
+               return -ENODEV;
+       }
+       if (!info->DeviceName[0]) {
+               uint16_t dev_name;
+
+               if (w1_max1721x_reg_get(info->w1_dev,
+                               MAX172XX_REG_DEVNAME, &dev_name)) {
+                       dev_err(info->w1_dev, "Can't read device name reg.\n");
+                       return -ENODEV;
+               }
+
+               switch (dev_name & MAX172XX_DEV_MASK) {
+               case MAX172X1_DEV:
+                       strncpy(info->DeviceName, DEF_DEV_NAME_MAX17211,
+                               2 * MAX1721X_REG_DEV_NUMB);
+                       break;
+               case MAX172X5_DEV:
+                       strncpy(info->DeviceName, DEF_DEV_NAME_MAX17215,
+                               2 * MAX1721X_REG_DEV_NUMB);
+                       break;
+               default:
+                       strncpy(info->DeviceName, DEF_DEV_NAME_UNKNOWN,
+                               2 * MAX1721X_REG_DEV_NUMB);
+               }
+       }
+
+       if (get_sn_string(info->w1_dev, info->SerialNumber)) {
+               dev_err(info->dev, "Can't read serial. Hardware error.\n");
+               return -ENODEV;
+       }
+
+       info->bat = power_supply_register(&pdev->dev, &info->bat_desc,
+                                               &psy_cfg);
+       if (IS_ERR(info->bat)) {
+               dev_err(info->dev, "failed to register battery\n");
+               return PTR_ERR(info->bat);
+       }
+
+       return 0;
+}
+
+static int max1721x_battery_remove(struct platform_device *pdev)
+{
+       struct max17211_device_info *info = platform_get_drvdata(pdev);
+
+       power_supply_unregister(info->bat);
+
+       return 0;
+}
+
+static struct platform_driver max1721x_battery_driver = {
+       .driver = {
+               .name = "max1721x-battery",
+       },
+       .probe    = max1721x_battery_probe,
+       .remove   = max1721x_battery_remove,
+};
+module_platform_driver(max1721x_battery_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alex A. Mihaylov <minimum...@rambler.ru>");
+MODULE_DESCRIPTION("Maxim MAX17211/MAX17215 Fuel Gauage IC driver");
+MODULE_ALIAS("platform:max1721x-battery");
-- 
2.8.4 (Apple Git-73)

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