The battery info functions computing the state-of-charge (SOC) based
on open-circuit-voltage (OCV) are returning SOC using units of 1%.
Some capacity estimation computations require higher accuracy. Add
functions that return SOC using units of 0.1% to reduce rounding error.
Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>
---
RFCv3 changes:
- Kerneldoc fixes
---
drivers/power/supply/power_supply_core.c | 65 ++++++++++++++++++++++++
include/linux/power_supply.h | 4 ++
2 files changed, 69 insertions(+)
diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index ebc961b5aa45..62ea113db3b4 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -1003,6 +1003,45 @@ int power_supply_ocv2cap_simple(struct power_supply_battery_ocv_table *table,
}
EXPORT_SYMBOL_GPL(power_supply_ocv2cap_simple);
+/**
+ * power_supply_ocv2dcap_simple() - find the battery capacity at 0.1% accuracy
+ * @table: Pointer to battery OCV lookup table
+ * @table_len: OCV table length
+ * @ocv: Current OCV value
+ *
+ * This helper function is used to look up battery capacity according to
+ * current OCV value from one OCV table, and the OCV table must be ordered
+ * descending. Return the SOC in the units of 0.1% for improved accuracy.
+ *
+ * Return: the battery capacity using the unit 0.1%.
+ */
+int power_supply_ocv2dcap_simple(struct power_supply_battery_ocv_table *table,
+ int table_len, int ocv)
+{
+ int i, cap, tmp;
+
+ for (i = 0; i < table_len; i++)
+ if (ocv > table[i].ocv)
+ break;
+
+ if (i > 0 && i < table_len) {
+ tmp = (table[i - 1].capacity - table[i].capacity) *
+ (ocv - table[i].ocv) * 10;
+ tmp /= table[i - 1].ocv - table[i].ocv;
+ cap = tmp + table[i].capacity * 10;
+ } else if (i == 0) {
+ cap = table[0].capacity * 10;
+ } else {
+ cap = table[table_len - 1].capacity * 10;
+ }
+
+ if (cap < 0)
+ cap = 0;
+
+ return cap;
+}
+EXPORT_SYMBOL_GPL(power_supply_ocv2dcap_simple);
+
struct power_supply_battery_ocv_table *
power_supply_find_ocv2cap_table(struct power_supply_battery_info *info,
int temp, int *table_len)
@@ -1054,6 +1093,32 @@ int power_supply_batinfo_dcap2ocv(struct power_supply_battery_info *info,
}
EXPORT_SYMBOL_GPL(power_supply_batinfo_dcap2ocv);
+/**
+ * power_supply_batinfo_ocv2dcap - compute SOC based on OCV and temperature
+ * @info: pointer to battery information
+ * @ocv: Open circuit voltage in uV
+ * @temp: Temperature in Celsius
+ *
+ * Use OCV tables in battery info to compute the battery capacity based on
+ * provided open circuit voltage at given and temperature.
+ *
+ * Return: battery capacity correspondinggiven OCV and temperature at 0.1%.
+ * -EINVAL if OCV table is not present.
+ */
+int power_supply_batinfo_ocv2dcap(struct power_supply_battery_info *info,
+ int ocv, int temp)
+{
+ struct power_supply_battery_ocv_table *table;
+ int table_len;
+
+ table = power_supply_find_ocv2cap_table(info, temp, &table_len);
+ if (!table)
+ return -EINVAL;
+
+ return power_supply_ocv2dcap_simple(table, table_len, ocv);
+}
+EXPORT_SYMBOL_GPL(power_supply_batinfo_ocv2dcap);
+
int power_supply_batinfo_ocv2cap(struct power_supply_battery_info *info,
int ocv, int temp)
{
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index c5118265b3ab..5e6575e97492 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -444,6 +444,10 @@ extern int power_supply_ocv2cap_simple(struct power_supply_battery_ocv_table *ta
int table_len, int ocv);
int power_supply_dcap2ocv_simple(struct power_supply_battery_ocv_table *table,
int table_len, int dcap);
+int power_supply_ocv2dcap_simple(struct power_supply_battery_ocv_table *table,
+ int table_len, int ocv);
+int power_supply_batinfo_ocv2dcap(struct power_supply_battery_info *info,
+ int ocv, int temp);
extern struct power_supply_battery_ocv_table *
power_supply_find_ocv2cap_table(struct power_supply_battery_info *info,
--
2.31.1
--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND
~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]
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