From ffebd90532728086007038986900426544e3df4e Mon Sep 17 00:00:00 2001
From: Prashant Malani <pmalani@chromium.org>
Date: Wed, 26 Jan 2022 19:02:20 +0000
Subject: [PATCH] platform/chrome: cros_ec_typec: Check for EC device
Git-commit: ffebd90532728086007038986900426544e3df4e
Patch-mainline: v5.18-rc1
References: git-fixes

The Type C ACPI device on older Chromebooks is not generated correctly
(since their EC firmware doesn't support the new commands required). In
such cases, the crafted ACPI device doesn't have an EC parent, and it is
therefore not useful (it shouldn't be generated in the first place since
the EC firmware doesn't support any of the Type C commands).

To handle devices which use these older firmware revisions, check for
the parent EC device handle, and fail the probe if it's not found.

Fixes: fdc6b21e2444 ("platform/chrome: Add Type C connector class driver")
Reported-by: Alyssa Ross <hi@alyssa.is>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Alyssa Ross <hi@alyssa.is>
Tested-by: Alyssa Ross <hi@alyssa.is>
Link: https://lore.kernel.org/r/20220126190219.3095419-1-pmalani@chromium.org
Signed-off-by: Benson Leung <bleung@chromium.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/platform/chrome/cros_ec_typec.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index ee12658009e5..c6f17e3ef72d 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -1076,7 +1076,13 @@ static int cros_typec_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	typec->dev = dev;
+
 	typec->ec = dev_get_drvdata(pdev->dev.parent);
+	if (!typec->ec) {
+		dev_err(dev, "couldn't find parent EC device\n");
+		return -ENODEV;
+	}
+
 	platform_set_drvdata(pdev, typec);
 
 	ret = cros_typec_get_cmd_version(typec);
-- 
2.31.1