media: v4l: common: v4l2_get_link_freq: add printing a warning

Print a warning if V4L2_CID_LINK_FREQ control is not implemented.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index 133d20e..04af032 100644 (file)
--- 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__);
        }
 
        return freq > 0 ? freq : -EINVAL;