The power-supply core supports concept of OCV (Open Circuit Voltage) =>
SOC (State Of Charge) conversion tables. Usually these tables are used
to estimate SOC based on OCV. Some systems use so called "Zero Adjust"
where at the near end-of-battery condition the SOC from coulomb counter
is used to retrieve the OCV - and OCV and VSYS difference is used to
re-estimate the battery capacity.
Add helper to do look-up the other-way around and also get the OCV
based on SOC
Signed-off-by: Matti Vaittinen <matti.vaitti...@fi.rohmeurope.com>
---
No changes from RFC v1 - (this should be changed to support at least
0.1% SOC accuracy - will rework for next version if this is continued)
drivers/power/supply/power_supply_core.c | 51 ++++++++++++++++++++++++
include/linux/power_supply.h | 5 +++
2 files changed, 56 insertions(+)
diff --git a/drivers/power/supply/power_supply_core.c
b/drivers/power/supply/power_supply_core.c
index 38e3aa642131..67258799ae2e 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -787,6 +787,43 @@ int power_supply_temp2resist_simple(struct
power_supply_resistance_temp_table *t
}
EXPORT_SYMBOL_GPL(power_supply_temp2resist_simple);
+/**
+ * power_supply_cap2ocv_simple() - find the battery OCV by capacity
+ * @table: Pointer to battery OCV/CAP lookup table
+ * @table_len: OCV/CAP table length
+ * @cap: Current cap value
+ *
+ * This helper function is used to look up battery OCV according to
+ * current capacity value from one OCV table, and the OCV table must be ordered
+ * descending.
+ *
+ * Return: the battery OCV.
+ */
+int power_supply_cap2ocv_simple(struct power_supply_battery_ocv_table *table,
+ int table_len, int cap)
+{
+ int i, ocv, tmp;
+
+ for (i = 0; i < table_len; i++)
+ if (cap > table[i].capacity)
+ break;
+
+ if (i > 0 && i < table_len) {
+ tmp = (table[i - 1].ocv - table[i].ocv) *
+ (cap - table[i].capacity);
+
+ tmp /= table[i - 1].capacity - table[i].capacity;
+ ocv = tmp + table[i].ocv;
+ } else if (i == 0) {
+ ocv = table[0].ocv;
+ } else {
+ ocv = table[table_len - 1].ocv;
+ }
+
+ return ocv;
+}
+EXPORT_SYMBOL_GPL(power_supply_cap2ocv_simple);
+
/**
* power_supply_ocv2cap_simple() - find the battery capacity
* @table: Pointer to battery OCV lookup table
@@ -847,6 +884,20 @@ power_supply_find_ocv2cap_table(struct
power_supply_battery_info *info,
}
EXPORT_SYMBOL_GPL(power_supply_find_ocv2cap_table);
+int power_supply_batinfo_cap2ocv(struct power_supply_battery_info *info,
+ int cap, 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_cap2ocv_simple(table, table_len, cap);
+}
+EXPORT_SYMBOL_GPL(power_supply_batinfo_cap2ocv);
+
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 81a55e974feb..bae98b628f92 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -403,11 +403,16 @@ extern void power_supply_put_battery_info(struct
power_supply *psy,
struct power_supply_battery_info
*info);
extern int power_supply_ocv2cap_simple(struct power_supply_battery_ocv_table
*table,
int table_len, int ocv);
+int power_supply_cap2ocv_simple(struct power_supply_battery_ocv_table *table,
+ int table_len, int cap);
+
extern struct power_supply_battery_ocv_table *
power_supply_find_ocv2cap_table(struct power_supply_battery_info *info,
int temp, int *table_len);
extern int power_supply_batinfo_ocv2cap(struct power_supply_battery_info *info,
int ocv, int temp);
+int power_supply_batinfo_cap2ocv(struct power_supply_battery_info *info,
+ int cap, int temp);
extern int
power_supply_temp2resist_simple(struct power_supply_resistance_temp_table
*table,
int table_len, int temp);
--
2.25.4
--
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 =]
