can: tcan4x5x: fix power regulator retrieval during probe

BugLink: https://bugs.launchpad.net/bugs/2120812

commit db22720545207f734aaa9d9f71637bfc8b0155e0 upstream.

Fixes the power regulator retrieval in tcan4x5x_can_probe() by ensuring
the regulator pointer is not set to NULL in the successful return from
devm_regulator_get_optional().

Fixes: 3814ca3 ("can: tcan4x5x: tcan4x5x_can_probe(): turn on the power before parsing the config")
Signed-off-by: Brett Werling <[email protected]>
Link: https://patch.msgid.link/[email protected]
Cc: [email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Noah Wager <[email protected]>
Signed-off-by: Stefan Bader <[email protected]>

Author: Brett Werling

drivers/net/can/m_can/tcan4x5x-core.c

@@ -411,10 +411,11 @@ static int tcan4x5x_can_probe(struct spi_device *spi)
 	priv = cdev_to_priv(mcan_class);
 
 	priv->power = devm_regulator_get_optional(&spi->dev, "vsup");
-	if (PTR_ERR(priv->power) == -EPROBE_DEFER) {
-		ret = -EPROBE_DEFER;
-		goto out_m_can_class_free_dev;
-	} else {
+	if (IS_ERR(priv->power)) {
+		if (PTR_ERR(priv->power) == -EPROBE_DEFER) {
+			ret = -EPROBE_DEFER;
+			goto out_m_can_class_free_dev;
+		}
 		priv->power = NULL;
 	}