| Message ID | 20230221171048.203042-3-jacopo.mondi@ideasonboard.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | media: i2c: ov5647: Add test pattern support | expand |
On Tue, Feb 21, 2023 at 06:10:48PM +0100, Jacopo Mondi wrote: > 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@ideasonboard.com> > Reviewed-by: Tommaso Merciai <tomm.merciai@gmail.com> > Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Actually, small change of e-mail address: Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> > --- > 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; > }
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; }