diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/regulator/pwm-regulator.c | 38 |
1 files changed, 23 insertions, 15 deletions
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c index f99a6970be29..8e928f23279b 100644 --- a/drivers/regulator/pwm-regulator.c +++ b/drivers/regulator/pwm-regulator.c @@ -113,18 +113,6 @@ static int pwm_regulator_is_enabled(struct regulator_dev *dev) return pwm_is_enabled(drvdata->pwm); } -/** - * Continuous voltage call-backs - */ -static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV) -{ - int min_uV = rdev->constraints->min_uV; - int max_uV = rdev->constraints->max_uV; - int diff = max_uV - min_uV; - - return ((req_uV * 100) - (min_uV * 100)) / diff; -} - static int pwm_regulator_get_voltage(struct regulator_dev *rdev) { struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); @@ -139,12 +127,32 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev, struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); unsigned int ramp_delay = rdev->constraints->ramp_delay; unsigned int period = pwm_get_period(drvdata->pwm); - int duty_cycle; + unsigned int req_diff = min_uV - rdev->constraints->min_uV; + unsigned int diff; + unsigned int duty_pulse; + u64 req_period; + u32 rem; int ret; - duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV); + diff = rdev->constraints->max_uV - rdev->constraints->min_uV; + + /* First try to find out if we get the iduty cycle time which is + * factor of PWM period time. If (request_diff_to_min * pwm_period) + * is perfect divided by voltage_range_diff then it is possible to + * get duty cycle time which is factor of PWM period. This will help + * to get output voltage nearer to requested value as there is no + * calculation loss. + */ + req_period = req_diff * period; + div_u64_rem(req_period, diff, &rem); + if (!rem) { + do_div(req_period, diff); + duty_pulse = (unsigned int)req_period; + } else { + duty_pulse = (period / 100) * ((req_diff * 100) / diff); + } - ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period); + ret = pwm_config(drvdata->pwm, duty_pulse, period); if (ret) { dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); return ret; |