platform/chrome: cros_ec_typec: Check for EC device

stable inclusion
from stable-v5.10.110
commit 16960ac92b84067ea1d0a2e6b8d7a5ba6fe32672
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=16960ac92b84067ea1d0a2e6b8d7a5ba6fe32672

--------------------------------

commit ffebd905 upstream.

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: fdc6b21e ("platform/chrome: Add Type C connector class driver")
Reported-by: NAlyssa Ross <hi@alyssa.is>
Reviewed-by: NTzung-Bi Shih <tzungbi@google.com>
Signed-off-by: NPrashant Malani <pmalani@chromium.org>
Acked-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: NAlyssa Ross <hi@alyssa.is>
Tested-by: NAlyssa Ross <hi@alyssa.is>
Link: https://lore.kernel.org/r/20220126190219.3095419-1-pmalani@chromium.orgSigned-off-by: NBenson Leung <bleung@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/platform/chrome/cros_ec_typec.c

@@ -712,7 +712,13 @@ 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);