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[media] tvp5150: make read operations atomic 

Instead of using two I2C operations between write and read,
use just one i2c_transfer. That allows I2C mutexes to not
let any other I2C transfer between the two.

Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Tested-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Mauro Carvalho Chehab 2013-12-26 23:07:22 -03:00
parent f7d40eea8e
commit 8de531b032
1 changed files with 10 additions and 14 deletions
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24
drivers/media/i2c/tvp5150.c
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@ -58,21 +58,17 @@ static int tvp5150_read(struct v4l2_subdev *sd, unsigned char addr)
struct i2c_client *c = v4l2_get_subdevdata(sd);
unsigned char buffer[1];
int rc;
struct i2c_msg msg[] = {
{ .addr = c->addr, .flags = 0,
.buf = &addr, .len = 1 },
{ .addr = c->addr, .flags = I2C_M_RD,
.buf = buffer, .len = 1 }
};
buffer[0] = addr;
rc = i2c_master_send(c, buffer, 1);
if (rc < 0) {
v4l2_err(sd, "i2c i/o error: rc == %d (should be 1)\n", rc);
return rc;
}
msleep(10);
rc = i2c_master_recv(c, buffer, 1);
if (rc < 0) {
v4l2_err(sd, "i2c i/o error: rc == %d (should be 1)\n", rc);
return rc;
rc = i2c_transfer(c->adapter, msg, 2);
if (rc < 0 || rc != 2) {
v4l2_err(sd, "i2c i/o error: rc == %d (should be 2)\n", rc);
return rc < 0 ? rc : -EIO;
}
v4l2_dbg(2, debug, sd, "tvp5150: read 0x%02x = 0x%02x\n", addr, buffer[0]);