power_supply: Add voltage_ocv property and use it for max17042 driver

This adds a new sysfs file called 'voltage_ocv' which gives the
Open Circuit Voltage of the battery.

This property can be used for platform shutdown policies and
can be useful for initial capacity estimations.

Note: This patch is generated against linux-next branch.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

4 files changed, 13 insertions, 0 deletions

diff --git a/Documentation/power/power_supply_class.txt b/Documentation/power/power_supply_class.txt
index 9f16c5178b66..211831d4095f 100644
--- a/Documentation/power/power_supply_class.txt
+++ b/Documentation/power/power_supply_class.txt
@@ -84,6 +84,8 @@ are already charged or discharging, 'n/a' can be displayed (or
 HEALTH - represents health of the battery, values corresponds to
 POWER_SUPPLY_HEALTH_*, defined in battery.h.
 
+VOLTAGE_OCV - open circuit voltage of the battery.
+
 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
diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 738648d1d9fc..42c4be9a664b 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -106,6 +106,7 @@ static enum power_supply_property max17042_battery_props[] = {
         POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
         POWER_SUPPLY_PROP_VOLTAGE_NOW,
         POWER_SUPPLY_PROP_VOLTAGE_AVG,
+        POWER_SUPPLY_PROP_VOLTAGE_OCV,
         POWER_SUPPLY_PROP_CAPACITY,
         POWER_SUPPLY_PROP_CHARGE_FULL,
         POWER_SUPPLY_PROP_TEMP,
@@ -172,6 +173,13 @@ static int max17042_get_property(struct power_supply *psy,
 
                 val->intval = ret * 625 / 8;
                 break;
+        case POWER_SUPPLY_PROP_VOLTAGE_OCV:
+                ret = max17042_read_reg(chip->client, MAX17042_OCVInternal);
+                if (ret < 0)
+                        return ret;
+
+                val->intval = ret * 625 / 8;
+                break;
         case POWER_SUPPLY_PROP_CAPACITY:
                 ret = max17042_read_reg(chip->client, MAX17042_RepSOC);
                 if (ret < 0)
diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
index 4368e7d61316..4150747f9186 100644
--- a/drivers/power/power_supply_sysfs.c
+++ b/drivers/power/power_supply_sysfs.c
@@ -146,6 +146,7 @@ static struct device_attribute power_supply_attrs[] = {
         POWER_SUPPLY_ATTR(voltage_min_design),
         POWER_SUPPLY_ATTR(voltage_now),
         POWER_SUPPLY_ATTR(voltage_avg),
+        POWER_SUPPLY_ATTR(voltage_ocv),
         POWER_SUPPLY_ATTR(current_max),
         POWER_SUPPLY_ATTR(current_now),
         POWER_SUPPLY_ATTR(current_avg),
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index c38c13db8832..fd17ae0f9c20 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -96,6 +96,7 @@ enum power_supply_property {
         POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
         POWER_SUPPLY_PROP_VOLTAGE_NOW,
         POWER_SUPPLY_PROP_VOLTAGE_AVG,
+        POWER_SUPPLY_PROP_VOLTAGE_OCV,
         POWER_SUPPLY_PROP_CURRENT_MAX,
         POWER_SUPPLY_PROP_CURRENT_NOW,
         POWER_SUPPLY_PROP_CURRENT_AVG,
@@ -261,6 +262,7 @@ static inline bool power_supply_is_watt_property(enum power_supply_property psp)
         case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+        case POWER_SUPPLY_PROP_VOLTAGE_OCV:
         case POWER_SUPPLY_PROP_POWER_NOW:
                 return 1;
         default: