regulator: as3711: Fix the logic in as3711_sel_check

Below equation means the "voltage" is the "smallest" voltage within specific
range.

ret = DIV_ROUND_UP(min - bottom) / step;
voltage = ret * step + bottom;

If we do try 1 down when (voltage > max), new voltage is then less than min
voltage. Which means the new voltage is not in the requested voltage range.

This patch also includes below cleanups:
- Use DIV_ROUND_UP
- rename variable 'ret' to 'sel' for better readability because as3711_sel_check
  returns the selector.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/drivers/regulator/as3711-regulator.c b/drivers/regulator/as3711-regulator.c
index 5e813b9059e7753aba801b1a813b99c51e7cff64..2f1341db38a0ad8d80802834244641a310a20399 100644 (file)
--- a/drivers/regulator/as3711-regulator.c
+++ b/drivers/regulator/as3711-regulator.c
@@ -93,24 +93,17 @@ static int as3711_bound_check(struct regulator_dev *rdev,
 
 static int as3711_sel_check(int min, int max, int bottom, int step)
 {
-       int ret, voltage;
+       int sel, voltage;
 
        /* Round up min, when dividing: keeps us within the range */
-       ret = (min - bottom + step - 1) / step;
-       voltage = ret * step + bottom;
+       sel = DIV_ROUND_UP(min - bottom, step);
+       voltage = sel * step + bottom;
        pr_debug("%s(): select %d..%d in %d+N*%d: %d\n", __func__,
-              min, max, bottom, step, ret);
-       if (voltage > max) {
-               /*
-                * Try 1 down. It will take us below min, but as long we stay
-                * above bottom, we're fine.
-                */
-               ret--;
-               voltage = ret * step + bottom;
-               if (voltage < bottom)
-                       return -EINVAL;
-       }
-       return ret;
+              min, max, bottom, step, sel);
+       if (voltage > max)
+               return -EINVAL;
+
+       return sel;
 }
 
 static int as3711_map_voltage_sd(struct regulator_dev *rdev,