mfd: as3711: Add OF support

Add Flat Device Tree support to the AS3711 MFD driver. This patch just
allows to bind the driver to I2C devices, instantiated from the DT.
DT support for AS3711 cell drivers will be added in separate drivers.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/as3711.c b/drivers/mfd/as3711.c
index e994c96..01e4141 100644
--- a/drivers/mfd/as3711.c
+++ b/drivers/mfd/as3711.c
@@ -112,16 +112,34 @@
 	.cache_type = REGCACHE_RBTREE,
 };
 
+#ifdef CONFIG_OF
+static struct of_device_id as3711_of_match[] = {
+	{.compatible = "ams,as3711",},
+	{}
+};
+MODULE_DEVICE_TABLE(of, as3711_of_match);
+#endif
+
 static int as3711_i2c_probe(struct i2c_client *client,
 			    const struct i2c_device_id *id)
 {
 	struct as3711 *as3711;
-	struct as3711_platform_data *pdata = client->dev.platform_data;
+	struct as3711_platform_data *pdata;
 	unsigned int id1, id2;
 	int ret;
 
-	if (!pdata)
-		dev_dbg(&client->dev, "Platform data not found\n");
+	if (!client->dev.of_node) {
+		pdata = client->dev.platform_data;
+		if (!pdata)
+			dev_dbg(&client->dev, "Platform data not found\n");
+	} else {
+		pdata = devm_kzalloc(&client->dev,
+				     sizeof(*pdata), GFP_KERNEL);
+		if (!pdata) {
+			dev_err(&client->dev, "Failed to allocate pdata\n");
+			return -ENOMEM;
+		}
+	}
 
 	as3711 = devm_kzalloc(&client->dev, sizeof(struct as3711), GFP_KERNEL);
 	if (!as3711) {
@@ -193,7 +211,8 @@
 	.driver = {
 		   .name = "as3711",
 		   .owner = THIS_MODULE,
-		   },
+		   .of_match_table = of_match_ptr(as3711_of_match),
+	},
 	.probe = as3711_i2c_probe,
 	.remove = as3711_i2c_remove,
 	.id_table = as3711_i2c_id,