hwmon: (amc6821) add of_match table

Add of_match table for "ti,amc6821" compatible string.
This fixes automatic driver loading by userspace when using device-tree,
and if built as a module like major linux distributions do.

While devices probe just fine with i2c_device_id table, userspace can't
match the "ti,amc6821" compatible string from dt with the plain
"amc6821" device id. As a result, the kernel module can not be loaded.

Cc: [email protected]
Signed-off-by: Josua Mayer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[groeck: Cleaned up patch description]
Signed-off-by: Guenter Roeck <[email protected]>

Author: Josua-SR

drivers/hwmon/amc6821.c

@@ -934,10 +934,21 @@ static const struct i2c_device_id amc6821_id[] = {
 
 MODULE_DEVICE_TABLE(i2c, amc6821_id);
 
+static const struct of_device_id __maybe_unused amc6821_of_match[] = {
+	{
+		.compatible = "ti,amc6821",
+		.data = (void *)amc6821,
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, amc6821_of_match);
+
 static struct i2c_driver amc6821_driver = {
 	.class = I2C_CLASS_HWMON,
 	.driver = {
 		.name	= "amc6821",
+		.of_match_table = of_match_ptr(amc6821_of_match),
 	},
 	.probe = amc6821_probe,
 	.id_table = amc6821_id,