2019-07-31 11:12:52

by Baolin Wang

[permalink] [raw]
Subject: [PATCH 3/6] power: supply: sc27xx: Fix the the accuracy issue of coulomb calculation

From: Yuanjiang Yu <[email protected]>

The Spreadtrum fuel gauge will multiply by 2 for counting the coulomb
counter to improve the accuracy, which means the value saved in fuel
gauge is: coulomb counter * 2 * 1000ma_adc. Thus fix the conversion
formular to improve the accuracy of calculating the battery capacity.

Signed-off-by: Yuanjiang Yu <[email protected]>
Signed-off-by: Baolin Wang <[email protected]>
---
drivers/power/supply/sc27xx_fuel_gauge.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/power/supply/sc27xx_fuel_gauge.c b/drivers/power/supply/sc27xx_fuel_gauge.c
index ca7b73e..ab3afa1 100644
--- a/drivers/power/supply/sc27xx_fuel_gauge.c
+++ b/drivers/power/supply/sc27xx_fuel_gauge.c
@@ -326,8 +326,6 @@ static int sc27xx_fgu_set_clbcnt(struct sc27xx_fgu_data *data, int clbcnt)
{
int ret;

- clbcnt *= SC27XX_FGU_SAMPLE_HZ;
-
ret = regmap_update_bits(data->regmap,
data->base + SC27XX_FGU_CLBCNT_SETL,
SC27XX_FGU_CLBCNT_MASK, clbcnt);
@@ -362,7 +360,6 @@ static int sc27xx_fgu_get_clbcnt(struct sc27xx_fgu_data *data, int *clb_cnt)

*clb_cnt = ccl & SC27XX_FGU_CLBCNT_MASK;
*clb_cnt |= (cch & SC27XX_FGU_CLBCNT_MASK) << SC27XX_FGU_CLBCNT_SHIFT;
- *clb_cnt /= SC27XX_FGU_SAMPLE_HZ;

return 0;
}
@@ -380,10 +377,10 @@ static int sc27xx_fgu_get_capacity(struct sc27xx_fgu_data *data, int *cap)

/*
* Convert coulomb counter to delta capacity (mAh), and set multiplier
- * as 100 to improve the precision.
+ * as 10 to improve the precision.
*/
- temp = DIV_ROUND_CLOSEST(delta_clbcnt, 360);
- temp = sc27xx_fgu_adc_to_current(data, temp);
+ temp = DIV_ROUND_CLOSEST(delta_clbcnt * 10, 36 * SC27XX_FGU_SAMPLE_HZ);
+ temp = sc27xx_fgu_adc_to_current(data, temp / 1000);

/*
* Convert to capacity percent of the battery total capacity,
@@ -790,7 +787,7 @@ static int sc27xx_fgu_cap_to_clbcnt(struct sc27xx_fgu_data *data, int capacity)
* Convert current capacity (mAh) to coulomb counter according to the
* formula: 1 mAh =3.6 coulomb.
*/
- return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc, 10);
+ return DIV_ROUND_CLOSEST(cur_cap * 36 * data->cur_1000ma_adc * SC27XX_FGU_SAMPLE_HZ, 10);
}

static int sc27xx_fgu_calibration(struct sc27xx_fgu_data *data)
--
1.7.9.5