media: rtl2830: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/media/dvb-frontends/rtl2830.c

@@ -24,9 +24,9 @@ static int rtl2830_bulk_write(struct i2c_client *client, unsigned int reg,
 	struct rtl2830_dev *dev = i2c_get_clientdata(client);
 	int ret;
 
-	i2c_lock_adapter(client->adapter);
+	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	ret = regmap_bulk_write(dev->regmap, reg, val, val_count);
-	i2c_unlock_adapter(client->adapter);
+	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	return ret;
 }
 
@@ -36,9 +36,9 @@ static int rtl2830_update_bits(struct i2c_client *client, unsigned int reg,
 	struct rtl2830_dev *dev = i2c_get_clientdata(client);
 	int ret;
 
-	i2c_lock_adapter(client->adapter);
+	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	ret = regmap_update_bits(dev->regmap, reg, mask, val);
-	i2c_unlock_adapter(client->adapter);
+	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	return ret;
 }
 
@@ -48,9 +48,9 @@ static int rtl2830_bulk_read(struct i2c_client *client, unsigned int reg,
 	struct rtl2830_dev *dev = i2c_get_clientdata(client);
 	int ret;
 
-	i2c_lock_adapter(client->adapter);
+	i2c_lock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	ret = regmap_bulk_read(dev->regmap, reg, val, val_count);
-	i2c_unlock_adapter(client->adapter);
+	i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
 	return ret;
 }