power: pm8921-bms: Add api to read Vsense
The Rsense resistor connects between the -ve end of the battery
and GND. The voltage across the Rsense gives us a good indication
of the current flowing through the battery.
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
diff --git a/drivers/power/pm8921-bms.c b/drivers/power/pm8921-bms.c
index e6e59de..eb98eed 100644
--- a/drivers/power/pm8921-bms.c
+++ b/drivers/power/pm8921-bms.c
@@ -285,6 +285,21 @@
return 0;
}
+static int read_vsense_avg(struct pm8921_bms_chip *chip, int *result)
+{
+ int rc;
+ int16_t reading;
+
+ rc = pm_bms_read_output_data(chip, VSENSE_AVG, &reading);
+ if (rc) {
+ pr_err("fail to read VSENSE_AVG rc = %d\n", rc);
+ return rc;
+ }
+ *result = CONV_READING(reading);
+ pr_debug("read = %04x vsense = %d\n", reading, *result);
+ return 0;
+}
+
static int linear_interpolate(int y0, int x0, int y1, int x1, int x)
{
if (y0 == y1 || x == x0)
@@ -709,6 +724,16 @@
return soc;
}
+int pm8921_bms_get_vsense_avg(int *result)
+{
+ if (the_chip)
+ return read_vsense_avg(the_chip, result);
+
+ pr_err("called before initialization\n");
+ return -EINVAL;
+}
+EXPORT_SYMBOL(pm8921_bms_get_vsense_avg);
+
int pm8921_bms_get_percent_charge(void)
{
int batt_temp, rc;
@@ -1004,6 +1029,9 @@
case OCV_FOR_RBATT:
read_ocv_for_rbatt(the_chip, (uint *)val);
break;
+ case VSENSE_AVG:
+ read_vsense_avg(the_chip, (uint *)val);
+ break;
default:
ret = -EINVAL;
}
@@ -1107,6 +1135,8 @@
(void *)VSENSE_FOR_RBATT, &reading_fops);
debugfs_create_file("read_ocv_for_rbatt", 0644, chip->dent,
(void *)OCV_FOR_RBATT, &reading_fops);
+ debugfs_create_file("read_vsense_avg", 0644, chip->dent,
+ (void *)VSENSE_AVG, &reading_fops);
debugfs_create_file("show_rbatt", 0644, chip->dent,
(void *)CALC_RBATT, &calc_fops);
diff --git a/include/linux/mfd/pm8xxx/pm8921-bms.h b/include/linux/mfd/pm8xxx/pm8921-bms.h
index 394553b..279e6f0 100644
--- a/include/linux/mfd/pm8xxx/pm8921-bms.h
+++ b/include/linux/mfd/pm8xxx/pm8921-bms.h
@@ -111,10 +111,23 @@
};
#if defined(CONFIG_PM8921_BMS) || defined(CONFIG_PM8921_BMS_MODULE)
+/**
+ * pm8921_bms_get_vsense_avg - return the voltage across the sense
+ * resitor in microvolts
+ * @result: The pointer where the voltage will be updated
+ *
+ * RETURNS: Error code if there was a problem reading vsense, Zero otherwise
+ * The result won't be updated in case of an error.
+ */
+int pm8921_bms_get_vsense_avg(int *result);
int pm8921_bms_get_percent_charge(void);
void pm8921_bms_charging_began(void);
void pm8921_bms_charging_end(void);
#else
+static inline int pm8921_bms_get_vsense_avg(int *result)
+{
+ return -ENXIO;
+}
static inline int pm8921_bms_get_percent_charge(void)
{
return -ENXIO;