can: tcan4x5x: tcan4x5x_can_probe(): turn on the power before parsing the config

The tcan4x5x_parse_config() function now performs action on the device
either reading or writing and a reset. If the devive has a switchable
power supppy (i.e. regulator is managed) it needs to be turned on.

So turn on the regulator if available. If the parsing fails, turn off
the regulator.

Fixes: 2de49735 ("can: tcan45x: Make wake-up GPIO an optional GPIO")
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/m_can/tcan4x5x.c

@@ -374,11 +374,6 @@ static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
 	if (IS_ERR(tcan4x5x->device_state_gpio))
 		tcan4x5x->device_state_gpio = NULL;
 
-	tcan4x5x->power = devm_regulator_get_optional(cdev->dev,
-						      "vsup");
-	if (PTR_ERR(tcan4x5x->power) == -EPROBE_DEFER)
-		return -EPROBE_DEFER;
-
 	return 0;
 }
 
@@ -412,6 +407,12 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	if (!priv)
 		return -ENOMEM;
 
+	priv->power = devm_regulator_get_optional(&spi->dev, "vsup");
+	if (PTR_ERR(priv->power) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+	else
+		priv->power = NULL;
+
 	mcan_class->device_data = priv;
 
 	m_can_class_get_clocks(mcan_class);
@@ -451,11 +452,13 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	priv->regmap = devm_regmap_init(&spi->dev, &tcan4x5x_bus,
 					&spi->dev, &tcan4x5x_regmap);
 
-	ret = tcan4x5x_parse_config(mcan_class);
+	ret = tcan4x5x_power_enable(priv->power, 1);
 	if (ret)
 		goto out_clk;
 
-	tcan4x5x_power_enable(priv->power, 1);
+	ret = tcan4x5x_parse_config(mcan_class);
+	if (ret)
+		goto out_power;
 
 	ret = tcan4x5x_init(mcan_class);
 	if (ret)