regulator: pwm: Retrieve correct voltage

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>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/regulator/pwm-regulator.c

@@ -37,9 +37,6 @@ struct pwm_regulator_data {
 
 	int state;
 
-	/* Continuous voltage */
-	int volt_uV;
-
 	/* Enable GPIO */
 	struct gpio_desc *enb_gpio;
 };
@@ -148,8 +145,13 @@ static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	int min_uV = rdev->constraints->min_uV;
+	int diff = rdev->constraints->max_uV - min_uV;
+	struct pwm_state pstate;
 
-	return drvdata->volt_uV;
+	pwm_get_state(drvdata->pwm, &pstate);
+
+	return min_uV + pwm_get_relative_duty_cycle(&pstate, diff);
 }
 
 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
@@ -176,8 +178,6 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 		return ret;
 	}
 
-	drvdata->volt_uV = min_uV;
-
 	if ((ramp_delay == 0) || !pwm_regulator_is_enabled(rdev))
 		return 0;