iio: adc: ina2xx: 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: Javier Martinez Canillas <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ina2xx-adc.c

···
 #include <linux/iio/sysfs.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/regmap.h>
 #include <linux/util_macros.h>
 
···
 	struct iio_dev *indio_dev;
 	struct iio_buffer *buffer;
 	unsigned int val;
+	enum ina2xx_ids type;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
···
 		return PTR_ERR(chip->regmap);
 	}
 
-	chip->config = &ina2xx_config[id->driver_data];
+	if (client->dev.of_node)
+		type = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
+	else
+		type = id->driver_data;
+	chip->config = &ina2xx_config[type];
 
 	mutex_init(&chip->state_lock);
 
···
 };
 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 
+static const struct of_device_id ina2xx_of_match[] = {
+	{
+		.compatible = "ti,ina219",
+		.data = (void *)ina219
+	},
+	{
+		.compatible = "ti,ina220",
+		.data = (void *)ina219
+	},
+	{
+		.compatible = "ti,ina226",
+		.data = (void *)ina226
+	},
+	{
+		.compatible = "ti,ina230",
+		.data = (void *)ina226
+	},
+	{
+		.compatible = "ti,ina231",
+		.data = (void *)ina226
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, ina2xx_of_match);
+
 static struct i2c_driver ina2xx_driver = {
 	.driver = {
 		   .name = KBUILD_MODNAME,
+		   .of_match_table = ina2xx_of_match,
 	},
 	.probe = ina2xx_probe,
 	.remove = ina2xx_remove,