mfd: Convert WM831x to use regmap API

Factor out the register read/write code to use the register map API.  We
still need some wm831x specific code and locking in place to check that
the user key is handled correctly but only on the write side, reads are
not affected by the key.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/wm831x-i2c.c b/drivers/mfd/wm831x-i2c.c
index a06cbc7..3ec6085 100644
--- a/drivers/mfd/wm831x-i2c.c
+++ b/drivers/mfd/wm831x-i2c.c
@@ -18,67 +18,17 @@
 #include <linux/delay.h>
 #include <linux/mfd/core.h>
 #include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/pdata.h>
 
-static int wm831x_i2c_read_device(struct wm831x *wm831x, unsigned short reg,
-				  int bytes, void *dest)
-{
-	struct i2c_client *i2c = wm831x->control_data;
-	int ret;
-	u16 r = cpu_to_be16(reg);
-
-	ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
-	if (ret < 0)
-		return ret;
-	if (ret != 2)
-		return -EIO;
-
-	ret = i2c_master_recv(i2c, dest, bytes);
-	if (ret < 0)
-		return ret;
-	if (ret != bytes)
-		return -EIO;
-	return 0;
-}
-
-/* Currently we allocate the write buffer on the stack; this is OK for
- * small writes - if we need to do large writes this will need to be
- * revised.
- */
-static int wm831x_i2c_write_device(struct wm831x *wm831x, unsigned short reg,
-				   int bytes, void *src)
-{
-	struct i2c_client *i2c = wm831x->control_data;
-	struct i2c_msg xfer[2];
-	int ret;
-
-	reg = cpu_to_be16(reg);
-
-	xfer[0].addr = i2c->addr;
-	xfer[0].flags = 0;
-	xfer[0].len = 2;
-	xfer[0].buf = (char *)&reg;
-
-	xfer[1].addr = i2c->addr;
-	xfer[1].flags = I2C_M_NOSTART;
-	xfer[1].len = bytes;
-	xfer[1].buf = (char *)src;
-
-	ret = i2c_transfer(i2c->adapter, xfer, 2);
-	if (ret < 0)
-		return ret;
-	if (ret != 2)
-		return -EIO;
-
-	return 0;
-}
-
 static int wm831x_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
 	struct wm831x *wm831x;
+	int ret;
 
 	wm831x = kzalloc(sizeof(struct wm831x), GFP_KERNEL);
 	if (wm831x == NULL)
@@ -86,9 +36,15 @@
 
 	i2c_set_clientdata(i2c, wm831x);
 	wm831x->dev = &i2c->dev;
-	wm831x->control_data = i2c;
-	wm831x->read_dev = wm831x_i2c_read_device;
-	wm831x->write_dev = wm831x_i2c_write_device;
+
+	wm831x->regmap = regmap_init_i2c(i2c, &wm831x_regmap_config);
+	if (IS_ERR(wm831x->regmap)) {
+		ret = PTR_ERR(wm831x->regmap);
+		dev_err(wm831x->dev, "Failed to allocate register map: %d\n",
+			ret);
+		kfree(wm831x);
+		return ret;
+	}
 
 	return wm831x_device_init(wm831x, id->driver_data, i2c->irq);
 }