power: pm8921-bms: fix hkadc readings
The procedure to calculate the battery voltage from xoadc raw readings
needs to be updated. Currently the driver multiplies the readings by 3
before calibration. This step needs to be done after calibration.
Also update all battery voltage based read_xxxx functions to
return the calibrated value.
Additionally call the hkadc calibration function at probe time
so early readings of battery voltage will be accurate.
Change-Id: I19c4ae8f124f3442ddffd651445db529ceac1cfe
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
diff --git a/drivers/power/pm8921-bms.c b/drivers/power/pm8921-bms.c
index 61b7608..fdbc819 100644
--- a/drivers/power/pm8921-bms.c
+++ b/drivers/power/pm8921-bms.c
@@ -339,25 +339,34 @@
return 0;
}
-#define V_PER_BIT_MUL_FACTOR 293
-#define INTRINSIC_OFFSET 0x6000
-static int vbatt_to_microvolt(unsigned int a)
+#define V_PER_BIT_MUL_FACTOR 97656
+#define V_PER_BIT_DIV_FACTOR 1000
+#define XOADC_INTRINSIC_OFFSET 0x6000
+static int xoadc_reading_to_microvolt(unsigned int a)
{
- if (a <= INTRINSIC_OFFSET)
+ if (a <= XOADC_INTRINSIC_OFFSET)
return 0;
- return (a - INTRINSIC_OFFSET) * V_PER_BIT_MUL_FACTOR;
+ return (a - XOADC_INTRINSIC_OFFSET)
+ * V_PER_BIT_MUL_FACTOR / V_PER_BIT_DIV_FACTOR;
}
#define XOADC_CALIB_UV 625000
-static int adjust_xo_reading(struct pm8921_bms_chip *chip, unsigned int uv)
+#define VBATT_MUL_FACTOR 3
+static int adjust_xo_vbatt_reading(struct pm8921_bms_chip *chip,
+ unsigned int uv)
{
- u64 numerator = ((u64)uv - chip->xoadc_v0625) * XOADC_CALIB_UV;
- u64 denominator = chip->xoadc_v125 - chip->xoadc_v0625;
+ u64 numerator, denominator;
+ if (uv == 0)
+ return 0;
+
+ numerator = ((u64)uv - chip->xoadc_v0625) * XOADC_CALIB_UV;
+ denominator = chip->xoadc_v125 - chip->xoadc_v0625;
if (denominator == 0)
- return uv;
- return XOADC_CALIB_UV + div_u64(numerator, denominator);
+ return uv * VBATT_MUL_FACTOR;
+ return (XOADC_CALIB_UV + div_u64(numerator, denominator))
+ * VBATT_MUL_FACTOR;
}
#define CC_RESOLUTION_N_V1 1085069
@@ -425,7 +434,7 @@
pr_err("fail to read LAST_GOOD_OCV_VALUE rc = %d\n", rc);
return rc;
}
- *result = vbatt_to_microvolt(reading);
+ *result = xoadc_reading_to_microvolt(reading);
pr_debug("raw = %04x ocv_microV = %u\n", reading, *result);
if (*result != 0)
last_ocv_uv = *result;
@@ -442,8 +451,10 @@
pr_err("fail to read VBATT_FOR_RBATT rc = %d\n", rc);
return rc;
}
- *result = vbatt_to_microvolt(reading);
+ *result = xoadc_reading_to_microvolt(reading);
pr_debug("raw = %04x vbatt_for_r_microV = %u\n", reading, *result);
+ *result = adjust_xo_vbatt_reading(chip, *result);
+ pr_debug("after adj vbatt_for_r_uV = %u\n", *result);
return 0;
}
@@ -472,8 +483,10 @@
pr_err("fail to read OCV_FOR_RBATT rc = %d\n", rc);
return rc;
}
- *result = vbatt_to_microvolt(reading);
- pr_debug("read = %04x ocv_for_r_microV = %u\n", reading, *result);
+ *result = xoadc_reading_to_microvolt(reading);
+ pr_debug("raw = %04x ocv_for_r_uV = %u\n", reading, *result);
+ *result = adjust_xo_vbatt_reading(chip, *result);
+ pr_debug("after adj ocv_for_r_uV = %u\n", *result);
return 0;
}
@@ -741,14 +754,12 @@
pr_err("fail to read ocv_for_rbatt rc = %d\n", rc);
ocv = 0;
}
- ocv = adjust_xo_reading(chip, ocv);
rc = read_vbatt_for_rbatt(chip, &vbatt);
if (rc) {
pr_err("fail to read vbatt_for_rbatt rc = %d\n", rc);
ocv = 0;
}
- vbatt = adjust_xo_reading(chip, vbatt);
rc = read_vsense_for_rbatt(chip, &vsense);
if (rc) {
@@ -1036,7 +1047,8 @@
#define HKADC_V_PER_BIT_DIV_FACTOR 10
static int calib_hkadc_convert_microvolt(unsigned int phy)
{
- return phy * HKADC_V_PER_BIT_MUL_FACTOR / HKADC_V_PER_BIT_DIV_FACTOR;
+ return (phy - 0x6000) *
+ HKADC_V_PER_BIT_MUL_FACTOR / HKADC_V_PER_BIT_DIV_FACTOR;
}
static void calib_hkadc(struct pm8921_bms_chip *chip)
@@ -1049,10 +1061,10 @@
pr_err("ADC failed for 1.25volts rc = %d\n", rc);
return;
}
- voltage = calib_hkadc_convert_microvolt(result.physical);
+ voltage = calib_hkadc_convert_microvolt(result.adc_code);
- pr_debug("result 1.25v = 0x%llx, voltage = %dmV adc_meas = %lld\n",
- result.physical, voltage, result.measurement);
+ pr_debug("result 1.25v = 0x%x, voltage = %duV adc_meas = %lld\n",
+ result.adc_code, voltage, result.measurement);
/* check for valid range */
if (voltage > XOADC_MAX_1P25V)
@@ -1066,9 +1078,9 @@
pr_err("ADC failed for 1.25volts rc = %d\n", rc);
return;
}
- voltage = calib_hkadc_convert_microvolt(result.physical);
- pr_debug("result 0.625V = 0x%llx, voltage = %dmV adc_mead = %lld\n",
- result.physical, voltage, result.measurement);
+ voltage = calib_hkadc_convert_microvolt(result.adc_code);
+ pr_debug("result 0.625V = 0x%x, voltage = %duV adc_mead = %lld\n",
+ result.adc_code, voltage, result.measurement);
/* check for valid range */
if (voltage > XOADC_MAX_0P625V)
voltage = XOADC_MAX_0P625V;
@@ -1373,6 +1385,7 @@
* if not compute it here at boot time and save it
* in the last_ocv_uv.
*/
+ ocv = 0;
rc = read_last_good_ocv(chip, &ocv);
if (rc || ocv == 0) {
rc = adc_based_ocv(chip, &ocv);
@@ -1677,9 +1690,11 @@
static int __devinit pm8921_bms_probe(struct platform_device *pdev)
{
int rc = 0;
+ int vbatt;
struct pm8921_bms_chip *chip;
const struct pm8921_bms_platform_data *pdata
= pdev->dev.platform_data;
+
if (!pdata) {
pr_err("missing platform data\n");
return -EINVAL;
@@ -1728,12 +1743,16 @@
check_initial_ocv(chip);
+ /* initial hkadc calibration */
+ schedule_work(&chip->calib_hkadc_work);
/* enable the vbatt reading interrupts for scheduling hkadc calib */
pm8921_bms_enable_irq(chip, PM8921_BMS_GOOD_OCV);
pm8921_bms_enable_irq(chip, PM8921_BMS_OCV_FOR_R);
- pr_info("OK battery_capacity_at_boot=%d\n",
- pm8921_bms_get_percent_charge());
+ get_battery_uvolts(chip, &vbatt);
+ pr_info("OK battery_capacity_at_boot=%d volt = %d ocv = %d\n",
+ pm8921_bms_get_percent_charge(),
+ vbatt, last_ocv_uv);
return 0;
free_chip: