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regulator: pwm-regulator: Simplify voltage to duty-cycle call

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If we reverse some of the logic and change the formula used,
we can simplify the function greatly.

It is intentional that this function is supplied and then re-worked
within the same patch-set.  The submission in the previous patch is
the tried and tested (i.e. in real releases) method written by ST.
This patch contains a simplification provided later.  It looks and
performs better, but doesn't have the same time-under-test that the
original method does.  The idea is that we keep some history in
order to provide an easy way back i.e. revert.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lee Jones 2015-07-07 16:06:52 +01:00 committed by Mark Brown
parent 4773be185a
commit cae897dec2
1 changed files with 6 additions and 19 deletions
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25
drivers/regulator/pwm-regulator.c
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@ -93,26 +93,13 @@ static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
/**
* Continuous voltage call-backs
*/
static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev,
int volt_mV)
static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev, int req_uV)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
int min_mV = rdev->constraints->min_uV / 1000;
int max_mV = rdev->constraints->max_uV / 1000;
int max_duty_cycle = drvdata->max_duty_cycle;
int vdiff = min_mV - max_mV;
int pwm_code;
int tmp;
int min_uV = rdev->constraints->min_uV;
int max_uV = rdev->constraints->max_uV;
int diff = max_uV - min_uV;
tmp = ((max_duty_cycle - min_mV) * max_duty_cycle) / vdiff;
pwm_code = ((tmp + max_duty_cycle) * volt_mV) / vdiff;
if (pwm_code < 0)
pwm_code = 0;
if (pwm_code > max_duty_cycle)
pwm_code = max_duty_cycle;
return pwm_code * 100 / max_duty_cycle;
return 100 - ((((req_uV * 100) - (min_uV * 100)) / diff));
}
static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
@ -131,7 +118,7 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
int duty_cycle;
int ret;
duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV / 1000);
duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV);
ret = pwm_config(drvdata->pwm,
(drvdata->pwm->period / 100) * duty_cycle,