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-rw-r--r--drivers/regulator/pwm-regulator.c38
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;