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: Jacopo Mondi <jacopo+rene...@jmondi.org>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Hans Verkuil <hans.verk...@cisco.com>
Cc: Sakari Ailus <sakari.ai...@linux.intel.com>
Cc: Mauro Carvalho Chehab <mche...@s-opensource.com>
Cc: Wolfram Sang <w...@the-dreams.de>
Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com>
---
* v4
- No changes
drivers/media/i2c/ov772x.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index e255070..b6223bf 100644
--- 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)
--
2.7.4
