[PATCH v5 30/46] regulator: pwm: retrieve correct voltage

Boris Brezillon
2016-03-30T20:03:53Z

The continuous PWM voltage regulator is caching the voltage value in
the ->volt_uV field. While most of the time this value should reflect the
real voltage, sometime it can be sightly different if the PWM device
rounded the set_duty_cycle request.
Moreover, this value is not valid until someone has modified the regulator
output.

Remove the ->volt_uV field and always rely on the PWM state to calculate
the regulator output.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
drivers/regulator/pwm-regulator.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 9374796..77f42d8 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -35,9 +35,6 @@ struct pwm_regulator_data {
struct regulator_ops ops;

int state;
-
- /* Continuous voltage */
- int volt_uV;
};

struct pwm_voltages {
@@ -167,11 +164,27 @@ static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int
return ((req_uV * 100) - (min_uV * 100)) / diff;
}

+static int pwm_duty_cycle_percentage_to_voltage(struct regulator_dev *rdev,
+ int dutycycle)
+{
+ int min_uV = rdev->constraints->min_uV;
+ int max_uV = rdev->constraints->max_uV;
+ int diff = max_uV - min_uV;
+
+ return min_uV + ((diff * dutycycle) / 100);
+}
+
static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+ struct pwm_state pstate;
+ u64 dutycycle;

- return drvdata->volt_uV;
+ pwm_get_state(drvdata->pwm, &pstate);
+ dutycycle = pstate.duty_cycle * 100;
+ do_div(dutycycle, pstate.period);
+
+ return pwm_duty_cycle_percentage_to_voltage(rdev, dutycycle);
}

static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
@@ -196,8 +209,6 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
return ret;
}

- drvdata->volt_uV = min_uV;
-
/* Delay required by PWM regulator to settle to the new voltage */
usleep_range(ramp_delay, ramp_delay + 1000);

--
2.5.0