regulator: max8998: Use simple equation to get selector

It's more efficient to get the best selector by simple equation.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/drivers/regulator/max8998.c b/drivers/regulator/max8998.c
index 74b0b0c..7e831a9 100644 (file)
--- a/drivers/regulator/max8998.c
+++ b/drivers/regulator/max8998.c
@@ -306,8 +306,7 @@ static int max8998_set_voltage_ldo(struct regulator_dev *rdev,
        int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
        const struct voltage_map_desc *desc;
        int ldo = rdev_get_id(rdev);
-       int reg, shift = 0, mask, ret;
-       int i = 0;
+       int reg, shift = 0, mask, ret, i;
 
        if (ldo >= ARRAY_SIZE(ldo_voltage_map))
                return -EINVAL;
@@ -319,9 +318,10 @@ static int max8998_set_voltage_ldo(struct regulator_dev *rdev,
        if (max_vol < desc->min || min_vol > desc->max)
                return -EINVAL;
 
-       while (desc->min + desc->step*i < min_vol &&
-              desc->min + desc->step*i < desc->max)
-               i++;
+       if (min_vol < desc->min)
+               min_vol = desc->min;
+
+       i = DIV_ROUND_UP(min_vol - desc->min, desc->step);
 
        if (desc->min + desc->step*i > max_vol)
                return -EINVAL;
@@ -359,7 +359,7 @@ static int max8998_set_voltage_buck(struct regulator_dev *rdev,
        const struct voltage_map_desc *desc;
        int buck = rdev_get_id(rdev);
        int reg, shift = 0, mask, ret;
-       int difference = 0, i = 0, j = 0, previous_vol = 0;
+       int difference = 0, i, j = 0, previous_vol = 0;
        u8 val = 0;
        static u8 buck1_last_val;
 
@@ -374,9 +374,10 @@ static int max8998_set_voltage_buck(struct regulator_dev *rdev,
        if (max_vol < desc->min || min_vol > desc->max)
                return -EINVAL;
 
-       while (desc->min + desc->step*i < min_vol &&
-              desc->min + desc->step*i < desc->max)
-               i++;
+       if (min_vol < desc->min)
+               min_vol = desc->min;
+
+       i = DIV_ROUND_UP(min_vol - desc->min, desc->step);
 
        if (desc->min + desc->step*i > max_vol)
                return -EINVAL;