Hi Sakari, On 6/27/19 6:05 PM, Sakari Ailus wrote: > Hi Hugues, > > On Thu, Jun 27, 2019 at 02:57:04PM +0200, Hugues Fruchet wrote: >> Add support of V4L2_CID_LINK_FREQ, this is needed >> by some CSI-2 receivers. >> >> 384MHz is exposed for the time being, corresponding >> to 96MHz pixel clock with 2 bytes per pixel on 2 data lanes. >> >> This setup has been tested successfully with ST MIPID02 >> CSI-2 to parallel bridge. >> >> Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx> >> --- > > Thanks for the patch. > > The driver calculates the sensor configuration based on its configuration, > and this needs to be reflected in the link frequency: it's not a static > value. See e.g. ov5640_calc_sys_clk(). > I know this code, but for a reason I don't understand yet, this seems to not have effects on the CSI-2 link frequency. This has been verified with MIPID02 CSI-2 bridge which only work with this fixed link frequency as input to program its ui_x4 register setting, see https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg2028171.html. All resolutions and all framerate have been tested succesfully with this setting. Initially I tried to set the link frequency according to the value computed in ov5640_calc_sys_clk() but it was only functional when resolutions/framerate was close to the 384MHz value... As OV5640 D3 engineering board has been initially developped for dragonboard, I'll dig into this and found this commit: https://lore.kernel.org/patchwork/patch/886794/ which set a fixed pixel rate value to 96MHz, which match perfectly with the 384MHz value I found for link frequency... Perhaps other CSI-2 OV5640 users can comment about it and have the explanations of what I experiment... Maxime, Jacopo, do you have any idea about it ? >> version 2: >> - do not set control read only as per Hans' comment: >> See https://www.mail-archive.com/linux-media@xxxxxxxxxxxxxxx/msg147910.html >> >> drivers/media/i2c/ov5640.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c >> index 82d4ce9..e6307f3 100644 >> --- a/drivers/media/i2c/ov5640.c >> +++ b/drivers/media/i2c/ov5640.c >> @@ -218,6 +218,7 @@ struct ov5640_ctrls { >> struct v4l2_ctrl *test_pattern; >> struct v4l2_ctrl *hflip; >> struct v4l2_ctrl *vflip; >> + struct v4l2_ctrl *link_freq; >> }; >> >> struct ov5640_dev { >> @@ -2198,6 +2199,10 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd, >> return 0; >> } >> >> +static const s64 link_freq_menu_items[] = { >> + 384000000, >> +}; >> + >> static int ov5640_set_fmt(struct v4l2_subdev *sd, >> struct v4l2_subdev_pad_config *cfg, >> struct v4l2_subdev_format *format) >> @@ -2636,6 +2641,8 @@ static int ov5640_s_ctrl(struct v4l2_ctrl *ctrl) >> case V4L2_CID_VFLIP: >> ret = ov5640_set_ctrl_vflip(sensor, ctrl->val); >> break; >> + case V4L2_CID_LINK_FREQ: >> + return 0; >> default: >> ret = -EINVAL; >> break; >> @@ -2703,6 +2710,9 @@ static int ov5640_init_controls(struct ov5640_dev *sensor) >> V4L2_CID_POWER_LINE_FREQUENCY_AUTO, 0, >> V4L2_CID_POWER_LINE_FREQUENCY_50HZ); >> >> + ctrls->link_freq = v4l2_ctrl_new_int_menu(hdl, ops, V4L2_CID_LINK_FREQ, >> + 0, 0, link_freq_menu_items); >> + >> if (hdl->error) { >> ret = hdl->error; >> goto free_ctrls; >> -- >> 2.7.4 >> > BR, Hugues.
