power: supply: sc27xx: Fix the the accuracy issue of coulomb calculation

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 <yuanjiang.yu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/drivers/power/supply/sc27xx_fuel_gauge.c b/drivers/power/supply/sc27xx_fuel_gauge.c
index db7d07d..6a29f00 100644 (file)
--- 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)