platform/x86: x86-android-tablets: Fix serdev instantiation no longer working

After commit b286f4e ("serial: core: Move tty and serdev to be
children of serial core port device") x86_instantiate_serdev() no longer
works due to the serdev-controller-device moving in the device hierarchy
from (e.g.) /sys/devices/pci0000:00/8086228A:00/serial0 to
/sys/devices/pci0000:00/8086228A:00/8086228A:00:0/8086228A:00:0.0/serial0

Use the new get_serdev_controller() helper function to fix this.

Fixes: b286f4e ("serial: core: Move tty and serdev to be children of serial core port device")
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240216201721.239791-4-hdegoede@redhat.com

Author: jwrdegoede

drivers/platform/x86/x86-android-tablets/core.c

@@ -21,6 +21,7 @@
 #include <linux/string.h>
 
 #include "x86-android-tablets.h"
+#include "../serdev_helpers.h"
 
 static struct platform_device *x86_android_tablet_device;
 
@@ -232,38 +233,20 @@ static __init int x86_instantiate_spi_dev(const struct x86_dev_info *dev_info, i
 
 static __init int x86_instantiate_serdev(const struct x86_serdev_info *info, int idx)
 {
-	struct acpi_device *ctrl_adev, *serdev_adev;
+	struct acpi_device *serdev_adev;
 	struct serdev_device *serdev;
 	struct device *ctrl_dev;
 	int ret = -ENODEV;
 
-	ctrl_adev = acpi_dev_get_first_match_dev(info->ctrl_hid, info->ctrl_uid, -1);
-	if (!ctrl_adev) {
-		pr_err("error could not get %s/%s ctrl adev\n",
-		       info->ctrl_hid, info->ctrl_uid);
-		return -ENODEV;
-	}
+	ctrl_dev = get_serdev_controller(info->ctrl_hid, info->ctrl_uid, 0,
+					 info->ctrl_devname);
+	if (IS_ERR(ctrl_dev))
+		return PTR_ERR(ctrl_dev);
 
 	serdev_adev = acpi_dev_get_first_match_dev(info->serdev_hid, NULL, -1);
 	if (!serdev_adev) {
 		pr_err("error could not get %s serdev adev\n", info->serdev_hid);
-		goto put_ctrl_adev;
-	}
-
-	/* get_first_physical_node() returns a weak ref, no need to put() it */
-	ctrl_dev = acpi_get_first_physical_node(ctrl_adev);
-	if (!ctrl_dev)	{
-		pr_err("error could not get %s/%s ctrl physical dev\n",
-		       info->ctrl_hid, info->ctrl_uid);
-		goto put_serdev_adev;
-	}
-
-	/* ctrl_dev now points to the controller's parent, get the controller */
-	ctrl_dev = device_find_child_by_name(ctrl_dev, info->ctrl_devname);
-	if (!ctrl_dev) {
-		pr_err("error could not get %s/%s %s ctrl dev\n",
-		       info->ctrl_hid, info->ctrl_uid, info->ctrl_devname);
-		goto put_serdev_adev;
+		goto put_ctrl_dev;
 	}
 
 	serdev = serdev_device_alloc(to_serdev_controller(ctrl_dev));
@@ -286,8 +269,8 @@ static __init int x86_instantiate_serdev(const struct x86_serdev_info *info, int
 
 put_serdev_adev:
 	acpi_dev_put(serdev_adev);
-put_ctrl_adev:
-	acpi_dev_put(ctrl_adev);
+put_ctrl_dev:
+	put_device(ctrl_dev);
 	return ret;
 }