ds2782_battery: Add support for ds2786 battery gas gauge

Signed-off-by: Yulia Vilensky <vilensky@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

2 files changed, 138 insertions, 50 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 22f2fa912127..c59bcb7c6eb0 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -65,10 +65,10 @@ config BATTERY_DS2760
           Say Y here to enable support for batteries with ds2760 chip.
 
 config BATTERY_DS2782
-        tristate "DS2782 standalone gas-gauge"
+        tristate "DS2782/DS2786 standalone gas-gauge"
         depends on I2C
         help
-          Say Y here to enable support for the DS2782 standalone battery
+          Say Y here to enable support for the DS2782/DS2786 standalone battery
           gas-gauge.
 
 config BATTERY_PMU
diff --git a/drivers/power/ds2782_battery.c b/drivers/power/ds2782_battery.c
index ba1bd1a545be..c665e8007235 100644
--- a/drivers/power/ds2782_battery.c
+++ b/drivers/power/ds2782_battery.c
@@ -5,6 +5,8 @@
  *
  * Author: Ryan Mallon <ryan@bluewatersys.com>
  *
+ * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
+ *
  * 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.
@@ -20,12 +22,13 @@
 #include <linux/idr.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#include <linux/ds2782_battery.h>
 
 #define DS2782_REG_RARC         0x06    /* Remaining active relative capacity */
 
-#define DS2782_REG_VOLT_MSB     0x0c
-#define DS2782_REG_TEMP_MSB     0x0a
-#define DS2782_REG_CURRENT_MSB  0x0e
+#define DS278x_REG_VOLT_MSB     0x0c
+#define DS278x_REG_TEMP_MSB     0x0a
+#define DS278x_REG_CURRENT_MSB  0x0e
 
 /* EEPROM Block */
 #define DS2782_REG_RSNSP        0x69    /* Sense resistor value */
@@ -33,18 +36,33 @@
 /* Current unit measurement in uA for a 1 milli-ohm sense resistor */
 #define DS2782_CURRENT_UNITS    1563
 
-#define to_ds2782_info(x) container_of(x, struct ds2782_info, battery)
+#define DS2786_REG_RARC         0x02    /* Remaining active relative capacity */
+
+#define DS2786_CURRENT_UNITS    25
+
+struct ds278x_info;
+
+struct ds278x_battery_ops {
+        int     (*get_current)(struct ds278x_info *info, int *current_uA);
+        int     (*get_voltage)(struct ds278x_info *info, int *voltage_uA);
+        int     (*get_capacity)(struct ds278x_info *info, int *capacity_uA);
+
+};
+
+#define to_ds278x_info(x) container_of(x, struct ds278x_info, battery)
 
-struct ds2782_info {
+struct ds278x_info {
         struct i2c_client       *client;
         struct power_supply     battery;
+        struct ds278x_battery_ops  *ops;
         int                     id;
+        int                     rsns;
 };
 
 static DEFINE_IDR(battery_id);
 static DEFINE_MUTEX(battery_lock);
 
-static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)
+static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
 {
         int ret;
 
@@ -58,7 +76,7 @@ static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)
         return 0;
 }
 
-static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
+static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
                                     s16 *val)
 {
         int ret;
@@ -73,7 +91,7 @@ static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
         return 0;
 }
 
-static int ds2782_get_temp(struct ds2782_info *info, int *temp)
+static int ds278x_get_temp(struct ds278x_info *info, int *temp)
 {
         s16 raw;
         int err;
@@ -84,14 +102,14 @@ static int ds2782_get_temp(struct ds2782_info *info, int *temp)
          * celsius. The temperature value is stored as a 10 bit number, plus
          * sign in the upper bits of a 16 bit register.
          */
-        err = ds2782_read_reg16(info, DS2782_REG_TEMP_MSB, &raw);
+        err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
         if (err)
                 return err;
         *temp = ((raw / 32) * 125) / 100;
         return 0;
 }
 
-static int ds2782_get_current(struct ds2782_info *info, int *current_uA)
+static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
 {
         int sense_res;
         int err;
@@ -102,7 +120,7 @@ static int ds2782_get_current(struct ds2782_info *info, int *current_uA)
          * The units of measurement for current are dependent on the value of
          * the sense resistor.
          */
-        err = ds2782_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
+        err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
         if (err)
                 return err;
         if (sense_res_raw == 0) {
@@ -113,14 +131,14 @@ static int ds2782_get_current(struct ds2782_info *info, int *current_uA)
 
         dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
                 sense_res);
-        err = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw);
+        err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
         if (err)
                 return err;
         *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
         return 0;
 }
 
-static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA)
+static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uA)
 {
         s16 raw;
         int err;
@@ -129,36 +147,77 @@ static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA)
          * Voltage is measured in units of 4.88mV. The voltage is stored as
          * a 10-bit number plus sign, in the upper bits of a 16-bit register
          */
-        err = ds2782_read_reg16(info, DS2782_REG_VOLT_MSB, &raw);
+        err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
         if (err)
                 return err;
         *voltage_uA = (raw / 32) * 4800;
         return 0;
 }
 
-static int ds2782_get_capacity(struct ds2782_info *info, int *capacity)
+static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
 {
         int err;
         u8 raw;
 
-        err = ds2782_read_reg(info, DS2782_REG_RARC, &raw);
+        err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
         if (err)
                 return err;
         *capacity = raw;
         return raw;
 }
 
-static int ds2782_get_status(struct ds2782_info *info, int *status)
+static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
+{
+        int err;
+        s16 raw;
+
+        err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
+        if (err)
+                return err;
+        *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
+        return 0;
+}
+
+static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uA)
+{
+        s16 raw;
+        int err;
+
+        /*
+         * Voltage is measured in units of 1.22mV. The voltage is stored as
+         * a 10-bit number plus sign, in the upper bits of a 16-bit register
+         */
+        err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
+        if (err)
+                return err;
+        *voltage_uA = (raw / 8) * 1220;
+        return 0;
+}
+
+static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
+{
+        int err;
+        u8 raw;
+
+        err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
+        if (err)
+                return err;
+        /* Relative capacity is displayed with resolution 0.5 % */
+        *capacity = raw/2 ;
+        return 0;
+}
+
+static int ds278x_get_status(struct ds278x_info *info, int *status)
 {
         int err;
         int current_uA;
         int capacity;
 
-        err = ds2782_get_current(info, &current_uA);
+        err = info->ops->get_current(info, &current_uA);
         if (err)
                 return err;
 
-        err = ds2782_get_capacity(info, &capacity);
+        err = info->ops->get_capacity(info, &capacity);
         if (err)
                 return err;
 
@@ -174,32 +233,32 @@ static int ds2782_get_status(struct ds2782_info *info, int *status)
         return 0;
 }
 
-static int ds2782_battery_get_property(struct power_supply *psy,
+static int ds278x_battery_get_property(struct power_supply *psy,
                                        enum power_supply_property prop,
                                        union power_supply_propval *val)
 {
-        struct ds2782_info *info = to_ds2782_info(psy);
+        struct ds278x_info *info = to_ds278x_info(psy);
         int ret;
 
         switch (prop) {
         case POWER_SUPPLY_PROP_STATUS:
-                ret = ds2782_get_status(info, &val->intval);
+                ret = ds278x_get_status(info, &val->intval);
                 break;
 
         case POWER_SUPPLY_PROP_CAPACITY:
-                ret = ds2782_get_capacity(info, &val->intval);
+                ret = info->ops->get_capacity(info, &val->intval);
                 break;
 
         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
-                ret = ds2782_get_voltage(info, &val->intval);
+                ret = info->ops->get_voltage(info, &val->intval);
                 break;
 
         case POWER_SUPPLY_PROP_CURRENT_NOW:
-                ret = ds2782_get_current(info, &val->intval);
+                ret = info->ops->get_current(info, &val->intval);
                 break;
 
         case POWER_SUPPLY_PROP_TEMP:
-                ret = ds2782_get_temp(info, &val->intval);
+                ret = ds278x_get_temp(info, &val->intval);
                 break;
 
         default:
@@ -209,7 +268,7 @@ static int ds2782_battery_get_property(struct power_supply *psy,
         return ret;
 }
 
-static enum power_supply_property ds2782_battery_props[] = {
+static enum power_supply_property ds278x_battery_props[] = {
         POWER_SUPPLY_PROP_STATUS,
         POWER_SUPPLY_PROP_CAPACITY,
         POWER_SUPPLY_PROP_VOLTAGE_NOW,
@@ -217,18 +276,18 @@ static enum power_supply_property ds2782_battery_props[] = {
         POWER_SUPPLY_PROP_TEMP,
 };
 
-static void ds2782_power_supply_init(struct power_supply *battery)
+static void ds278x_power_supply_init(struct power_supply *battery)
 {
         battery->type                   = POWER_SUPPLY_TYPE_BATTERY;
-        battery->properties             = ds2782_battery_props;
-        battery->num_properties         = ARRAY_SIZE(ds2782_battery_props);
-        battery->get_property           = ds2782_battery_get_property;
+        battery->properties             = ds278x_battery_props;
+        battery->num_properties         = ARRAY_SIZE(ds278x_battery_props);
+        battery->get_property           = ds278x_battery_get_property;
         battery->external_power_changed = NULL;
 }
 
-static int ds2782_battery_remove(struct i2c_client *client)
+static int ds278x_battery_remove(struct i2c_client *client)
 {
-        struct ds2782_info *info = i2c_get_clientdata(client);
+        struct ds278x_info *info = i2c_get_clientdata(client);
 
         power_supply_unregister(&info->battery);
         kfree(info->battery.name);
@@ -241,13 +300,36 @@ static int ds2782_battery_remove(struct i2c_client *client)
         return 0;
 }
 
-static int ds2782_battery_probe(struct i2c_client *client,
+static struct ds278x_battery_ops ds278x_ops[] = {
+        [0] = {
+                .get_current  = ds2782_get_current,
+                .get_voltage  = ds2782_get_voltage,
+                .get_capacity = ds2782_get_capacity,
+        },
+        [1] = {
+                .get_current  = ds2786_get_current,
+                .get_voltage  = ds2786_get_voltage,
+                .get_capacity = ds2786_get_capacity,
+        }
+};
+
+static int ds278x_battery_probe(struct i2c_client *client,
                                 const struct i2c_device_id *id)
 {
-        struct ds2782_info *info;
+        struct ds278x_platform_data *pdata = client->dev.platform_data;
+        struct ds278x_info *info;
         int ret;
         int num;
 
+        /*
+         * ds2786 should have the sense resistor value set
+         * in the platform data
+         */
+        if (id->driver_data == 1 && !pdata) {
+                dev_err(&client->dev, "missing platform data for ds2786\n");
+                return -EINVAL;
+        }
+
         /* Get an ID for this battery */
         ret = idr_pre_get(&battery_id, GFP_KERNEL);
         if (ret == 0) {
@@ -267,15 +349,20 @@ static int ds2782_battery_probe(struct i2c_client *client,
                 goto fail_info;
         }
 
-        info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num);
+        info->battery.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num);
         if (!info->battery.name) {
                 ret = -ENOMEM;
                 goto fail_name;
         }
 
+        if (id->driver_data == 1)
+                info->rsns = pdata->rsns;
+
         i2c_set_clientdata(client, info);
         info->client = client;
-        ds2782_power_supply_init(&info->battery);
+        info->id = num;
+        info->ops  = &ds278x_ops[id->driver_data];
+        ds278x_power_supply_init(&info->battery);
 
         ret = power_supply_register(&client->dev, &info->battery);
         if (ret) {
@@ -297,31 +384,32 @@ fail_id:
         return ret;
 }
 
-static const struct i2c_device_id ds2782_id[] = {
+static const struct i2c_device_id ds278x_id[] = {
         {"ds2782", 0},
+        {"ds2786", 1},
         {},
 };
 
-static struct i2c_driver ds2782_battery_driver = {
+static struct i2c_driver ds278x_battery_driver = {
         .driver         = {
                 .name   = "ds2782-battery",
         },
-        .probe          = ds2782_battery_probe,
-        .remove         = ds2782_battery_remove,
-        .id_table       = ds2782_id,
+        .probe          = ds278x_battery_probe,
+        .remove         = ds278x_battery_remove,
+        .id_table       = ds278x_id,
 };
 
-static int __init ds2782_init(void)
+static int __init ds278x_init(void)
 {
-        return i2c_add_driver(&ds2782_battery_driver);
+        return i2c_add_driver(&ds278x_battery_driver);
 }
-module_init(ds2782_init);
+module_init(ds278x_init);
 
-static void __exit ds2782_exit(void)
+static void __exit ds278x_exit(void)
 {
-        i2c_del_driver(&ds2782_battery_driver);
+        i2c_del_driver(&ds278x_battery_driver);
 }
-module_exit(ds2782_exit);
+module_exit(ds278x_exit);
 
 MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>");
 MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");