Le mer. 12 juin 2024 à 10:06, AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> a écrit : > > Il 10/06/24 16:39, Julien Stephan ha scritto: [...] > >> > >>> + writel(0x10001, input->base + SENINF_TG1_SEN_CK); > >> > >> Unroll this one... this is the TG1 sensor clock divider. > >> > >> CLKFL GENMASK(5, 0) > >> CLKRS GENMASK(13, 8) > >> CLKCNT GENMASK(21,16) > >> > >> Like this, I don't get what you're trying to set, because you're using a fixed > >> sensor clock rate, meaning that only a handful of camera sensors will be usable. > >> > >> Is this 8Mhz? 16? 24? what? :-) > >> > >> Two hints: > >> - sensor_clk = clk_get_rate(isp_clk) / (tg1_sen_ck_clkcnt + 1); > >> - int mtk_seninf_set_sensor_clk(u8 rate_mhz); > >> > >> Please :-) > > > > Hi Angelo, > > > > I think I get your point about not hardcoding the sensor rate, but I > > am not sure how to use > > a mtk_seninf_set_sensor_clk(u8 rate_mhz); function. > > > > Where would it be called? How is it exposed to the user? > > > > As for where: setup, streaming start, resolution change (which may be covered > by streaming start anyway, as a change should be calling stop->start anyway). > > And for the how is it exposed to the user - well, depends what you mean for user, > but it's all standard V4L2 API :-) > > Last but not least, I can give you another hint.... > > struct media_entity *entity = (something_here); > struct media_pad *mpad; > struct v4l2_subdev *cam_subdev; > struct v4l2_ctrl *ctl; > s64 link_frequency, pixel_clock; > > if (entity->pads[0].flags & MEDIA_PAD_FL_SINK) > return -E_NOT_A_CAMERA_SENSOR_WE_IGNORE_THIS_ONE; > > pad = media_pad_remote_pad_first(&entity->pads[0]); > if (!pad) > return -ENOENT; > > if (!is_media_entity_v4l2_subdev(pad->entity)) > return -ENOENT; > > if (pad->entity->function != MEDIA_ENT_F_CAM_SENSOR) > return -ENOENT; > Hi Angelo, Thank you for the detailed explanation :) However, I can't make it work because in my case, seninf is connected to an external ISP so pad->entity->function == MEDIA_ENT_F_PROC_VIDEO_ISP. How can I get the pad corresponding to the sensor? > cam_subdev = media_entity_to_v4l2_subdev(pad->entity); > ctl = v4l2_ctrl_find(subdev->ctrl_handler, V4L2_CID_PIXEL_RATE); > Is this mandatory to implement V4L2_CID_PIXEL_RATE ? Should I return an error if not found? > /* multiplier is usually bits per pixel, divider is usually num of lanes */ > link_frequency = v4l2_get_link_freq(cam_subdev->ctrl_handler, multiplier, divider); > pixel_clock = v4l2_ctrl_g_ctrl_int64(ctl); > How to know the sensor clock given link_frequency and pixel_clock? Can you point me to drivers doing something similar? Cheers, Julien > > ....now you know what the sensor wants, set the seninf sensor clock accordingly. > > Cheers > Angelo > [...] Cheers Julien
