[PATCH v4 2/3] platform/x86: dell-uart-backlight: Bind through normal serdev matching

[ChunAn Wu <an.wu@canonical.com>]

The driver creates a serdev client without firmware metadata and
force-attaches its driver to it.

Pass the modalias to serdev_device_add() and give the serdev driver a
matching id_table, so that the serdev core binds the two through normal
matching, then drop the manual attachment.

The client now also reports a "serial:dell_uart_backlight" modalias to
userspace instead of failing with -ENODEV. A failing serdev probe no
longer propagates out of the platform probe; as for any other bus, the
client is simply left unbound.

Signed-off-by: ChunAn Wu <an.wu@canonical.com>
---
 .../platform/x86/dell/dell-uart-backlight.c    | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-uart-backlight.c b/drivers/platform/x86/dell/dell-uart-backlight.c
index f323a667dc2d..9b8ef91bb0a2 100644
--- a/drivers/platform/x86/dell/dell-uart-backlight.c
+++ b/drivers/platform/x86/dell/dell-uart-backlight.c
@@ -325,11 +325,17 @@ static int dell_uart_bl_serdev_probe(struct serdev_device *serdev)
 	return PTR_ERR_OR_ZERO(dell_bl->bl);
 }
 
+static const struct serdev_device_id dell_uart_bl_serdev_id[] = {
+	{ KBUILD_MODNAME },
+	{ }
+};
+
 static struct serdev_device_driver dell_uart_bl_serdev_driver = {
 	.probe = dell_uart_bl_serdev_probe,
 	.driver = {
 		.name = KBUILD_MODNAME,
 	},
+	.id_table = dell_uart_bl_serdev_id,
 };
 
 static int dell_uart_bl_pdev_probe(struct platform_device *pdev)
@@ -354,7 +360,7 @@ static int dell_uart_bl_pdev_probe(struct platform_device *pdev)
 	if (!serdev)
 		return -ENOMEM;
 
-	ret = serdev_device_add(serdev);
+	ret = serdev_device_add(serdev, KBUILD_MODNAME);
 	if (ret) {
 		dev_err(&pdev->dev, "error %d adding serdev\n", ret);
 		serdev_device_put(serdev);
@@ -365,20 +371,10 @@ static int dell_uart_bl_pdev_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_remove_serdev;
 
-	/*
-	 * serdev device <-> driver matching relies on OF or ACPI matches and
-	 * neither is available here, manually bind the driver.
-	 */
-	ret = device_driver_attach(&dell_uart_bl_serdev_driver.driver, &serdev->dev);
-	if (ret)
-		goto err_unregister_serdev_driver;
-
 	/* So that dell_uart_bl_pdev_remove() can remove the serdev */
 	platform_set_drvdata(pdev, serdev);
 	return 0;
 
-err_unregister_serdev_driver:
-	serdev_device_driver_unregister(&dell_uart_bl_serdev_driver);
 err_remove_serdev:
 	serdev_device_remove(serdev);
 	return ret;
-- 
2.34.1