regulator: pwm: Properly initialize the ->state field

The ->state field is currently initialized to 0, thus referencing the
voltage selector at index 0, which might not reflect the current
voltage value.
If possible, retrieve the current voltage selector from the PWM state,
else return -EINVAL.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
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

@@ -52,10 +52,31 @@ struct pwm_voltages {
 /**
  * Voltage table call-backs
  */
+static void pwm_regulator_init_state(struct regulator_dev *rdev)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	struct pwm_state pwm_state;
+	unsigned int dutycycle;
+	int i;
+
+	pwm_get_state(drvdata->pwm, &pwm_state);
+	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
+
+	for (i = 0; i < rdev->desc->n_voltages; i++) {
+		if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
+			drvdata->state = i;
+			return;
+		}
+	}
+}
+
 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 
+	if (drvdata->state < 0)
+		pwm_regulator_init_state(rdev);
+
 	return drvdata->state;
 }
 
@@ -221,6 +242,7 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 		return ret;
 	}
 
+	drvdata->state			= -EINVAL;
 	drvdata->duty_cycle_table	= duty_cycle_table;
 	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 	       sizeof(drvdata->ops));