media: ov772x: allow i2c controllers without I2C_FUNC_PROTOCOL_MANGLING

The ov772x driver only works when the i2c controller have
I2C_FUNC_PROTOCOL_MANGLING.  However, many i2c controller drivers don't
support it.

The reason that the ov772x requires I2C_FUNC_PROTOCOL_MANGLING is that
it doesn't support repeated starts.

This changes the reading ov772x register method so that it doesn't
require I2C_FUNC_PROTOCOL_MANGLING by calling two separated i2c messages.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index e255070..b6223bf 100644 (file)
--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -542,9 +542,19 @@ static struct ov772x_priv *to_ov772x(struct v4l2_subdev *sd)
        return container_of(sd, struct ov772x_priv, subdev);
 }
 
-static inline int ov772x_read(struct i2c_client *client, u8 addr)
+static int ov772x_read(struct i2c_client *client, u8 addr)
 {
-       return i2c_smbus_read_byte_data(client, addr);
+       int ret;
+       u8 val;
+
+       ret = i2c_master_send(client, &addr, 1);
+       if (ret < 0)
+               return ret;
+       ret = i2c_master_recv(client, &val, 1);
+       if (ret < 0)
+               return ret;
+
+       return val;
 }
 
 static inline int ov772x_write(struct i2c_client *client, u8 addr, u8 value)
@@ -1255,13 +1265,11 @@ static int ov772x_probe(struct i2c_client *client,
                return -EINVAL;
        }
 
-       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
-                                             I2C_FUNC_PROTOCOL_MANGLING)) {
+       if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(&adapter->dev,
-                       "I2C-Adapter doesn't support SMBUS_BYTE_DATA or PROTOCOL_MANGLING\n");
+                       "I2C-Adapter doesn't support SMBUS_BYTE_DATA\n");
                return -EIO;
        }
-       client->flags |= I2C_CLIENT_SCCB;
 
        priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)