platform/chrome: cros_ec_typec: Check ec platform device pointer

It is possible that parent device for cros_ec_typec device is already
available, but ec pointer in parent driver data isn't populated yet. It
may happen when cros_typec_probe is running in parallel with
cros_ec_register. This leads to NULL pointer dereference when
cros_typec_probe tries to get driver data from typec->ec->ec->dev.

Check if typec->ec->ec is set before using it in cros_typec_probe.

Signed-off-by: Tomasz Michalec <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Tzung-Bi Shih <[email protected]>

Author: Chimstaz

drivers/platform/chrome/cros_ec_typec.c

@@ -1354,7 +1354,7 @@ static int cros_typec_probe(struct platform_device *pdev)
 	typec->dev = dev;
 
 	typec->ec = dev_get_drvdata(pdev->dev.parent);
-	if (!typec->ec) {
+	if (!typec->ec || !typec->ec->ec) {
 		dev_warn(dev, "couldn't find parent EC device\n");
 		return -EPROBE_DEFER;
 	}