hwmon: (pmbus/lm25066) Add OF device ID table

The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. This is working on the assumption that a
I2C device registered via OF will always match a legacy I2C device ID and
that the MODALIAS reported will always be of the form i2c:<device>.

But this could change in the future so the correct approach is to have an
OF device ID table if the devices are registered via OF.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20210928092242.30036-7-zev@bewilderbeest.net
[groeck: Replaced reference to reasoning with reasoning, fixed checkpatch
 warnings, fixed compile warning comparing of_id->data w/ i2c_id->driver_data]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/lm25066.c

@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/log2.h>
+#include <linux/of_device.h>
 #include "pmbus.h"
 
 enum chips { lm25056, lm25066, lm5064, lm5066, lm5066i };
@@ -444,12 +445,24 @@ static const struct i2c_device_id lm25066_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, lm25066_id);
 
+static const struct of_device_id __maybe_unused lm25066_of_match[] = {
+	{ .compatible = "ti,lm25056", .data = (void *)lm25056, },
+	{ .compatible = "ti,lm25066", .data = (void *)lm25066, },
+	{ .compatible = "ti,lm5064",  .data = (void *)lm5064,  },
+	{ .compatible = "ti,lm5066",  .data = (void *)lm5066,  },
+	{ .compatible = "ti,lm5066i", .data = (void *)lm5066i, },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, lm25066_of_match);
+
 static int lm25066_probe(struct i2c_client *client)
 {
 	int config;
 	struct lm25066_data *data;
 	struct pmbus_driver_info *info;
 	const struct __coeff *coeff;
+	const struct of_device_id *of_id;
+	const struct i2c_device_id *i2c_id;
 
 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_READ_BYTE_DATA))
@@ -464,7 +477,14 @@ static int lm25066_probe(struct i2c_client *client)
 	if (config < 0)
 		return config;
 
-	data->id = i2c_match_id(lm25066_id, client)->driver_data;
+	i2c_id = i2c_match_id(lm25066_id, client);
+
+	of_id = of_match_device(lm25066_of_match, &client->dev);
+	if (of_id && (unsigned long)of_id->data != i2c_id->driver_data)
+		dev_notice(&client->dev, "Device mismatch: %s in device tree, %s detected\n",
+			   of_id->name, i2c_id->name);
+
+	data->id = i2c_id->driver_data;
 	info = &data->info;
 
 	info->pages = 1;
@@ -521,7 +541,8 @@ static int lm25066_probe(struct i2c_client *client)
 static struct i2c_driver lm25066_driver = {
 	.driver = {
 		   .name = "lm25066",
-		   },
+		   .of_match_table = of_match_ptr(lm25066_of_match),
+	},
 	.probe_new = lm25066_probe,
 	.id_table = lm25066_id,
 };