Hi Martin, On Thu, Dec 10, 2020 at 11:24:00AM +0200, Laurent Pinchart wrote: > On Thu, Dec 10, 2020 at 09:17:48AM +0100, Martin Kepplinger wrote: > > hi, > > > > TL;DR: did you use the NXP "mx6s_capture" csi bridge driver with other > > cameras? > > I've recently worked on camera support for i.MX8MM (whose camera IP > cores are, if not identical, very similar to the i.MX8MQ's). The least I > can say is that it was painful :-( > > I'm using an MT9M114 sensor, which can produce RAW8, RAW10 and YUV and > has a CSI-2 interface. My first use case is to capture RAW10, which > isn't supported by the mx6s_capture driver. > > > I try to use a CSI2 camera (hi846 I'm writing a driver for) on imx8mq: > > Using NXP's CSI bridge driver > > https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/mxc/capture/mx6s_capture.c?h=imx_5.4.0_8dxlphantom_er > > as well as the CSI driver itself: > > https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/imx8/mxc-mipi-csi2_yav.c?h=imx_5.4.0_8dxlphantom_er > > works fine when using the ov5640 camera with this driver: > > https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/mxc/capture/ov5640_mipi_v2.c?h=imx_5.4.0_8dxlphantom_er > > > > (I realize there is a CSI bridge driver in staging, but that need more > > work to be actually used. Of course after this the goal is to fix and > > use it; and mainline a CSI phy driver too.) > > I have lots of patches for this driver, which I've developed on i.MX7D > for a separate project. I'd like to mainline them, but this is blocked > by one last issue that I haven't been able to solve yet. In a nutshell, > the CSI writes two consecutive frames in each buffer, overflowing the > allocated memory. The registers that control the buffer size seem to be > programmed correctly as far as I can tell. I've reported this issue to > NXP but haven't received any feedback yet. > > I've also added support for i.MX8MM to this driver, but haven't been > able to capture RAW8, RAW10 or YUV successfully. YUV produces the "best > images", but seems to drop 3 out of 4 consecutive pixels. The sensor > driver has been tested successfully on i.MX6 so I don't think it's the > most likely cause of issues, but I can't rule out bugs on that side > either. The i.MX8 reference manuals describe the MIPI_CSI and CSI IP > cores but doesn't tell much about how the two are connected, so I have > lots of unanswered questions about the register fields that control the > interface between those IP cores. I'm pretty sure there are issues in > that area of the drivers, but I've tested all combinations I could think > of, without luck. > > > Now I use said NXP's CSI drivers on mainline without problems with the > > ov5640. For the hi846 (as an example), I want to use a different > > pixelformat and CSI media bus format. Describing, say, > > MEDIA_BUS_FMT_SBGGR10_1X10 in the driver lets mx6s_capture find it; but > > as soon as I try to add a different pixelformat than V4L2_PIX_FMT_UYVY in: > > https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/media/platform/mxc/capture/mx6s_capture.c?h=imx_5.4.0_8dxlphantom_er#n244 > > streaming won't start anymore: "not negotiated, -4" and the > > "mx6s_vidioc_enum_framesizes" ioctl is not called anymore. Why so? > > That will likely be the easy part of the problem. The NXP driver doesn't > support RAW10 at all, so you will have to add that, and I don't think it > will be easy. > > I'll push my development branch shortly if you're interested in trying > the mainline driver. git://linuxtv.org/pinchartl/media.git imx/csi/imx8 The topmost patches are random debugging tests. > > I didn't find much when comparing strace from "gst-launch-1.0 v4l2src ! > > video/x-raw,width=1280,height=720 ! videoconvert ! xvimagesink" (which > > is how I test). > > > > When I simply use V4L2_PIX_FMT_UYVY I *do* get interrupts (in mx6s) but > > only "FIELD0_INT" (and drawing at this point suggests that buffer 1 is > > not yet full and "distorted" in a wrong format, which could explain why > > DMA is never completed in order to create a full frame). > > > > Now this is details, but the hi846 camera uses a 10bit CSI format and > > therefore I need to set PIXEL_BIT in cr1 too, but when I do that for > > example, I don't get "FIELD0_INT" anymore (only SFF_OR_INT and of course > > the "base address switching Change Err"). > > > > Do you have experience with using this driver with other cameras and can > > point me in a direction that might help me? > > > > If you want to look at the work-in-progress driver: > > https://source.puri.sm/martin.kepplinger/linux-next/-/blob/hi846/drivers/media/i2c/hi846.c -- Regards, Laurent Pinchart
