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    Subject[PATCH RFT 1/2] regulator: twl: Fix the formula to calculate vsel and voltage for twl6030ldo
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    In twl6030ldo_set_voltage, current code use below formula to calculate vsel:
    vsel = (min_uV/1000 - 1000)/100 + 1;
    This is worng because when min_uV is 1000000 uV, vsel is 1.
    It should be 0 in this case.
    Fix it by change the equation to: (This equation is common for linear mapping)
    vsel = DIV_ROUND_UP(min_uV - rdev->desc->min_uV, rdev->desc->uV_step);

    In twl6030ldo_get_voltage, current code use below formula to calculate voltage:
    mV = 1000mv + 100mv * (vsel - 1)
    This is worng because when vsel is 0, mV is 900mV. Note the min_uV is 1000mV.
    Fix it by change the equation to: (This equation is common for linear mapping)
    return rdev->desc->min_uV + vsel * rdev->desc->uV_step;

    Signed-off-by: Axel Lin <axel.lin@gmail.com>
    ---
    drivers/regulator/twl-regulator.c | 17 ++++-------------
    1 file changed, 4 insertions(+), 13 deletions(-)

    diff --git a/drivers/regulator/twl-regulator.c b/drivers/regulator/twl-regulator.c
    index 8f0bd56..bb51dec 100644
    --- a/drivers/regulator/twl-regulator.c
    +++ b/drivers/regulator/twl-regulator.c
    @@ -569,30 +569,21 @@ twl6030ldo_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV,
    if ((min_uV/1000 < info->min_mV) || (max_uV/1000 > info->max_mV))
    return -EDOM;

    - /*
    - * Use the below formula to calculate vsel
    - * mV = 1000mv + 100mv * (vsel - 1)
    - */
    - vsel = (min_uV/1000 - 1000)/100 + 1;
    + vsel = DIV_ROUND_UP(min_uV - rdev->desc->min_uV, rdev->desc->uV_step);
    *selector = vsel;
    - return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE, vsel);

    + return twlreg_write(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE, vsel);
    }

    static int twl6030ldo_get_voltage(struct regulator_dev *rdev)
    {
    struct twlreg_info *info = rdev_get_drvdata(rdev);
    - int vsel = twlreg_read(info, TWL_MODULE_PM_RECEIVER,
    - VREG_VOLTAGE);
    + int vsel = twlreg_read(info, TWL_MODULE_PM_RECEIVER, VREG_VOLTAGE);

    if (vsel < 0)
    return vsel;

    - /*
    - * Use the below formula to calculate vsel
    - * mV = 1000mv + 100mv * (vsel - 1)
    - */
    - return (1000 + (100 * (vsel - 1))) * 1000;
    + return rdev->desc->min_uV + vsel * rdev->desc->uV_step;
    }

    static struct regulator_ops twl6030ldo_ops = {
    --
    1.7.9.5




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