Thank you for reply! I`m sorry that I did not describe my problem clearly. In tvp5150 driver,the v4l2 controls(VIDIOC_G_CTRL like)that i need are already implemented. part of the driver as follow: static int tvp5150_command(struct i2c_client *c,unsigned int cmd, void *arg) { struct tvp5150 *decoder = i2c_get_clientdata(c); switch (cmd) { case 0: case VIDIOC_INT_RESET: ... case VIDIOC_G_CTRL: ... } static struct i2c_driver driver = { .driver = { .name = "tvp5150", }, .id = I2C_DRIVERID_TVP5150, .attach_adapter = tvp5150_attach_adapter, .detach_client = tvp5150_detach_client, .command = tvp5150_command, }; I want to access the tvp5150_command function in userland . I opened /dev/i2c-0 and called ioctl like that: if (ioctl(file,I2C_SLAVE_FORCE,addr) < 0) { /*addr is tvp5150 address*/ exit(1); } if (ioctl(file,VIDIOC_G_CTRL,addr) < 0) ... It`s absolute wrong but I don`t know how to call VIDIOC_G_CTRL control. Regards, william 2009/5/23 Markus Rechberger <mrechberger@xxxxxxxxx> > 2009/5/22 Devin Heitmueller <dheitmueller@xxxxxxxxxxxxxx>: > > On Fri, May 22, 2009 at 3:50 AM, 景文林 <wenlinjing@xxxxxxxxx> wrote: > >> Hi, > >> > >> I am working with a video capture chip TVP5150. I want to adjust the > >> "Brightness" "Contrast" "Saturation" and "hue" in user space. > >> In TVP5150 drivers ,the V4l2 commands are in function > tvp5150_command.And > >> this function is a member of struct i2c_device. > >> > >> The linux is 2.6.19.2. > >> I write my code according kernel document > Documentation/i2c/dev-interface > >> But I can`t access tvp5150_command. > >> How can i acces i2c_device .command function from user space? > > > > I thought those controls were already implemented in the tvp5150 > > driver, although I could be mistaken (I would have to look at the > > code). If not, it would probably be much easier to just add the > > commands to the driver than to attempt to program the chip from > > userland (the datasheet for the tvp5150 is freely available). > > > > those are definitely implemented, I remember there was a problem with > a too dark videopicture years ago and it was a bug in the tvp5150... > > Also by looking at it: > V4L2_CID_BRIGHTNESS > V4L2_CID_CONTRAST > V4L2_CID_SATURATION > V4L2_CID_HUE > > are supported. > > Markus > -- video4linux-list mailing list Unsubscribe mailto:video4linux-list-request@xxxxxxxxxx?subjecthttps://www.redhat.com/mailman/listinfo/video4linux-list