Re: [PATCH RFT 1/2] regulator: twl: Fix checking voltage range in twl6030smps_set_voltage()

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Copying Graeme and linux-omap list.

On Saturday 14 July 2012 11:07 AM, Axel Lin wrote:
The voltage selection logic is supposed to find the samllest voltage falls
within specified range. When using equation to calculate vsel, we need to
ensure the requested min_uV meet the range of using the equation.
Otherwise we may select a voltage that is out of specified range.

For example, in the case vsel = 62 means select voltage of 2100000uV.
What we want is to ensure the requested min_uV<= 2100000 rather than checking
max_uV>= 2100000. And this also means in the case min_uV>  2100000, vsel = 62
does not meet the request.

Also calling twl6030smps_list_voltage() for all cases to ensure the selected
voltage still in bounds.

Signed-off-by: Axel Lin<axel.lin@xxxxxxxxx>
---
  drivers/regulator/twl-regulator.c |   36 ++++++++++++++++--------------------
  1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/drivers/regulator/twl-regulator.c b/drivers/regulator/twl-regulator.c
index 8f0bd56..03d0bea 100644
--- a/drivers/regulator/twl-regulator.c
+++ b/drivers/regulator/twl-regulator.c
@@ -760,32 +760,28 @@ twl6030smps_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV,
  			unsigned int *selector)
  {
  	struct twlreg_info	*info = rdev_get_drvdata(rdev);
-	int	vsel = 0;
+	int vsel = 0, calc_uV;

  	switch (info->flags) {
  	case 0:
  		if (min_uV == 0)
  			vsel = 0;
  		else if ((min_uV>= 600000)&&  (min_uV<= 1300000)) {
-			int calc_uV;
  			vsel = DIV_ROUND_UP(min_uV - 600000, 12500);
  			vsel++;
-			calc_uV = twl6030smps_list_voltage(rdev, vsel);
-			if (calc_uV>  max_uV)
-				return -EINVAL;
  		}
  		/* Values 1..57 for vsel are linear and can be calculated
  		 * values 58..62 are non linear.
  		 */
-		else if ((min_uV>  1900000)&&  (max_uV>= 2100000))
+		else if ((min_uV>  1900000)&&  (min_uV<= 2100000))
  			vsel = 62;
-		else if ((min_uV>  1800000)&&  (max_uV>= 1900000))
+		else if ((min_uV>  1800000)&&  (min_uV<= 1900000))
  			vsel = 61;
-		else if ((min_uV>  1500000)&&  (max_uV>= 1800000))
+		else if ((min_uV>  1500000)&&  (min_uV<= 1800000))
  			vsel = 60;
-		else if ((min_uV>  1350000)&&  (max_uV>= 1500000))
+		else if ((min_uV>  1350000)&&  (min_uV<= 1500000))
  			vsel = 59;
-		else if ((min_uV>  1300000)&&  (max_uV>= 1350000))
+		else if ((min_uV>  1300000)&&  (min_uV<= 1350000))
  			vsel = 58;
  		else
  			return -EINVAL;
@@ -794,25 +790,21 @@ twl6030smps_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV,
  		if (min_uV == 0)
  			vsel = 0;
  		else if ((min_uV>= 700000)&&  (min_uV<= 1420000)) {
-			int calc_uV;
  			vsel = DIV_ROUND_UP(min_uV - 700000, 12500);
  			vsel++;
-			calc_uV = twl6030smps_list_voltage(rdev, vsel);
-			if (calc_uV>  max_uV)
-				return -EINVAL;
  		}
  		/* Values 1..57 for vsel are linear and can be calculated
  		 * values 58..62 are non linear.
  		 */
-		else if ((min_uV>  1900000)&&  (max_uV>= 2100000))
+		else if ((min_uV>  1900000)&&  (min_uV<= 2100000))
  			vsel = 62;
-		else if ((min_uV>  1800000)&&  (max_uV>= 1900000))
+		else if ((min_uV>  1800000)&&  (min_uV<= 1900000))
  			vsel = 61;
-		else if ((min_uV>  1350000)&&  (max_uV>= 1800000))
+		else if ((min_uV>  1350000)&&  (min_uV<= 1800000))
  			vsel = 60;
-		else if ((min_uV>  1350000)&&  (max_uV>= 1500000))
+		else if ((min_uV>  1350000)&&  (min_uV<= 1500000))
  			vsel = 59;
-		else if ((min_uV>  1300000)&&  (max_uV>= 1350000))
+		else if ((min_uV>  1300000)&&  (min_uV<= 1350000))
  			vsel = 58;
  		else
  			return -EINVAL;
@@ -828,13 +820,17 @@ twl6030smps_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV,
  	case SMPS_OFFSET_EN|SMPS_EXTENDED_EN:
  		if (min_uV == 0) {
  			vsel = 0;
-		} else if ((min_uV>= 2161000)&&  (max_uV<= 4321000)) {
+		} else if ((min_uV>= 2161000)&&  (min_uV<= 4321000)) {
  			vsel = DIV_ROUND_UP(min_uV - 2161000, 38600);
  			vsel++;
  		}
  		break;
  	}

+	calc_uV = twl6030smps_list_voltage(rdev, vsel);
+	if (calc_uV>  max_uV)
+		return -EINVAL;
+
  	*selector = vsel;

  	return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE_SMPS,

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