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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>
This commit is contained in:
Axel Lin 2012-11-24 00:53:22 +08:00 committed by Mark Brown
parent 16ed9f0701
commit 7a4beda0c6
1 changed files with 8 additions and 15 deletions
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23
drivers/regulator/as3711-regulator.c
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@ -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,