The ov5647_read() functions calls i2c_master_send() and
i2c_master_read() in sequence. However this leaves space for other
clients to contend the bus and insert an unrelated transaction in between
the two calls.
Replace the two calls with a single i2c_transfer() one, that locks the
bus in between the transactions.
Signed-off-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
Reviewed-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx>
Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
drivers/media/i2c/ov5647.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
index bde287e00c87..ca7079bb7589 100644
--- a/drivers/media/i2c/ov5647.c
+++ b/drivers/media/i2c/ov5647.c
@@ -629,23 +629,29 @@ static int ov5647_write(struct v4l2_subdev *sd, u16 reg, u8 val)
static int ov5647_read(struct v4l2_subdev *sd, u16 reg, u8 *val)
{
- unsigned char data_w[2] = { reg >> 8, reg & 0xff };
struct i2c_client *client = v4l2_get_subdevdata(sd);
+ u8 buf[2] = { reg >> 8, reg & 0xff };
+ struct i2c_msg msg[2];
int ret;
- ret = i2c_master_send(client, data_w, 2);
- if (ret < 0) {
- dev_dbg(&client->dev, "%s: i2c write error, reg: %x\n",
- __func__, reg);
- return ret;
+ msg[0].addr = client->addr;
+ msg[0].flags = client->flags;
+ msg[0].buf = buf;
+ msg[0].len = sizeof(buf);
+
+ msg[1].addr = client->addr;
+ msg[1].flags = client->flags | I2C_M_RD;
+ msg[1].buf = buf;
+ msg[1].len = 1;
+
+ ret = i2c_transfer(client->adapter, msg, 2);
+ if (ret != 2) {
+ dev_err(&client->dev, "%s: i2c read error, reg: %x = %d\n",
+ __func__, reg, ret);
+ return ret >= 0 ? -EINVAL : ret;
}
- ret = i2c_master_recv(client, val, 1);
- if (ret < 0) {
- dev_dbg(&client->dev, "%s: i2c read error, reg: %x\n",
- __func__, reg);
- return ret;
- }
+ *val = buf[0];
return 0;
}
--
2.39.0
