[PATCH] media: st-mipid02: add support of V4L2_CID_LINK_FREQ

[Hugues Fruchet]

Ask device connected on sink pad for link frequency
in order to configure CLK_LANE_REG1 (ui_x4).
If not available, ask for pixel rate information to compute it.

This is needed to deal with compressed format such as JPEG
where number of bits per pixel is unknown: computation of
link frequency from pixel rate is not possible.

Signed-off-by: Hugues Fruchet <hugues.fruc...@st.com>
---
 drivers/media/i2c/st-mipid02.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/media/i2c/st-mipid02.c b/drivers/media/i2c/st-mipid02.c
index 9369f38..8623f30 100644
--- a/drivers/media/i2c/st-mipid02.c
+++ b/drivers/media/i2c/st-mipid02.c
@@ -331,6 +331,25 @@ static int mipid02_detect(struct mipid02_dev *bridge)
        return mipid02_read_reg(bridge, MIPID02_CLK_LANE_WR_REG1, &reg);
 }
 
+static u32 mipid02_get_link_freq_from_cid_link_freq(struct mipid02_dev *bridge,
+                                                   struct v4l2_subdev *subdev)
+{
+       struct v4l2_querymenu qm = {.id = V4L2_CID_LINK_FREQ, };
+       struct v4l2_ctrl *ctrl;
+       int ret;
+
+       ctrl = v4l2_ctrl_find(subdev->ctrl_handler, V4L2_CID_LINK_FREQ);
+       if (!ctrl)
+               return 0;
+       qm.index = v4l2_ctrl_g_ctrl(ctrl);
+
+       ret = v4l2_querymenu(subdev->ctrl_handler, &qm);
+       if (ret)
+               return 0;
+
+       return qm.value;
+}
+
 static u32 mipid02_get_link_freq_from_cid_pixel_rate(struct mipid02_dev 
*bridge,
                                                     struct v4l2_subdev *subdev)
 {
@@ -358,10 +377,14 @@ static int mipid02_configure_from_rx_speed(struct 
mipid02_dev *bridge)
        struct v4l2_subdev *subdev = bridge->s_subdev;
        u32 link_freq;
 
-       link_freq = mipid02_get_link_freq_from_cid_pixel_rate(bridge, subdev);
+       link_freq = mipid02_get_link_freq_from_cid_link_freq(bridge, subdev);
        if (!link_freq) {
-               dev_err(&client->dev, "Failed to detect link frequency");
-               return -EINVAL;
+               link_freq = mipid02_get_link_freq_from_cid_pixel_rate(bridge,
+                                                                     subdev);
+               if (!link_freq) {
+                       dev_err(&client->dev, "Failed to get link frequency");
+                       return -EINVAL;
+               }
        }
 
        dev_dbg(&client->dev, "detect link_freq = %d Hz", link_freq);
-- 
2.7.4