em28xx-i2c: rt_mutex_trylock() returns zero on failure

commit e44c153b30c9a0580fc2b5a93f3c6d593def2278 upstream.

The code is checking for negative returns but it should be checking for
zero.

Fixes: aab3125c43d8 ('[media] em28xx: add support for registering multiple i2c buses')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c b/drivers/media/usb/em28xx/em28xx-i2c.c
index b58d4ebf641928dd535f9b1870398ab674e93c38..6c1737828d5fa0b7ec0914a49ef93e53c747fa3f 100644 (file)
--- a/drivers/media/usb/em28xx/em28xx-i2c.c
+++ b/drivers/media/usb/em28xx/em28xx-i2c.c
@@ -501,9 +501,8 @@ static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
        int addr, rc, i;
        u8 reg;
 
-       rc = rt_mutex_trylock(&dev->i2c_bus_lock);
-       if (rc < 0)
-               return rc;
+       if (!rt_mutex_trylock(&dev->i2c_bus_lock))
+               return -EAGAIN;
 
        /* Switch I2C bus if needed */
        if (bus != dev->cur_i2c_bus &&