Hi Andrey, Thank you for the patch. On Thu, Feb 18, 2021 at 08:16:40PM +0300, Andrey Konovalov wrote: > Print a warning if V4L2_CID_LINK_FREQ control is not implemented. > > Signed-off-by: Andrey Konovalov <andrey.konovalov@xxxxxxxxxx> > Reviewed-by: Jacopo Mondi <jacopo@xxxxxxxxxx> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > --- > drivers/media/v4l2-core/v4l2-common.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c > index 133d20e40f82..04af03285a20 100644 > --- a/drivers/media/v4l2-core/v4l2-common.c > +++ b/drivers/media/v4l2-core/v4l2-common.c > @@ -469,6 +469,11 @@ s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul, > return -ENOENT; > > freq = div_u64(v4l2_ctrl_g_ctrl_int64(ctrl) * mul, div); > + > + pr_warn("%s: Link frequency estimated using pixel rate: result might be inaccurate\n", > + __func__); > + pr_warn("%s: Consider implementing support for V4L2_CID_LINK_FREQ in the transmitter driver\n", > + __func__); It would still be nice if v4l2_ctrl_handler was extended with a struct device pointer to use dev_warn() here, and allow replacing "the transmitter driver" with the driver name. > } > > return freq > 0 ? freq : -EINVAL; -- Regards, Laurent Pinchart