regulator: ad5398: Add device tree support

Previously, the ad5398 driver used only platform_data, which is
deprecated in favour of device tree. This caused the AD5398 to fail to
probe as it could not load its init_data. If the AD5398 has a device
tree node, pull the init_data from there using
of_get_regulator_init_data.

Signed-off-by: Isaac Scott <isaac.scott@ideasonboard.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Link: https://patch.msgid.link/20250128173143.959600-4-isaac.scott@ideasonboard.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: ijgscott

drivers/regulator/ad5398.c

@@ -14,6 +14,7 @@
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
 
 #define AD5398_SW_POWER_DOWN	BIT(16)
 
@@ -221,15 +222,20 @@ static int ad5398_probe(struct i2c_client *client)
 	const struct ad5398_current_data_format *df =
 			(struct ad5398_current_data_format *)id->driver_data;
 
-	if (!init_data)
-		return -EINVAL;
-
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
 
 	config.dev = &client->dev;
+	if (client->dev.of_node)
+		init_data = of_get_regulator_init_data(&client->dev,
+						       client->dev.of_node,
+						       &ad5398_reg);
+	if (!init_data)
+		return -EINVAL;
+
 	config.init_data = init_data;
+	config.of_node = client->dev.of_node;
 	config.driver_data = chip;
 
 	chip->client = client;