2011/3/30 Laurent Pinchart <laurent.pinch...@ideasonboard.com>: > Hi Bastian, > > On Wednesday 30 March 2011 11:41:44 Bastian Hecht wrote: >> 2011/3/29 Laurent Pinchart <laurent.pinch...@ideasonboard.com>: >> > On Friday 25 March 2011 13:34:10 Bastian Hecht wrote: >> >> 2011/3/24 Bastian Hecht <hec...@googlemail.com>: >> >> > 2011/3/24 Laurent Pinchart <laurent.pinch...@ideasonboard.com>: >> >> >> On Thursday 24 March 2011 10:59:01 Bastian Hecht wrote: >> >> >>> 2011/3/22 Laurent Pinchart <laurent.pinch...@ideasonboard.com>: >> >> >>> > On Tuesday 22 March 2011 17:11:04 Bastian Hecht wrote: >> >> >>> >> Hello omap isp devs, >> >> >>> >> >> >> >>> >> maybe you can help me, I am a bit desperate with my current cam >> >> >>> >> problem: >> >> >>> >> >> >> >>> >> I use a ov5642 chip and get only 0x55 in my data output when I >> >> >>> >> use a camclk > 1 MHz. With 1 MHz data rate from the camera chip >> >> >>> >> to the omap all works (well the colorspace is strange - it's >> >> >>> >> greenish, but that is not my main concern). >> >> >>> >> I looked up the data on the oscilloscope and all flanks seem to >> >> >>> >> be fine at the isp. Very clear cuts with 4 MHz and 10MHz. Also >> >> >>> >> the data pins are flickering fine. Looks like a picture. >> >> >>> >> >> >> >>> >> I found that the isp stats module uses 0x55 as a magic number but >> >> >>> >> I don't see why it should confuse my readout. >> >> >>> >> >> >> >>> >> I use 2592x1944 raw bayer output via the ccdc. Next to the >> >> >>> >> logical right config I tried all possible configurations of >> >> >>> >> vs/hs active high and low on camera and isp. The isp gets the vs >> >> >>> >> flanks right as the images come out in time (sometimes it misses >> >> >>> >> 1 frame). >> >> >>> >> >> >> >>> >> Anyone of you had this behaviour before? >> >> >>> > >> >> >>> > How do you capture images ? yavta will fill buffers with 0x55 >> >> >>> > before queueing them, so this might indicate that no data is >> >> >>> > written to the buffer at all. >> >> >>> >> >> >>> Yes I use yavta. So what does that all mean? >> >> >> >> >> >> It means that the ISP doesn't write data to the buffer. I have no >> >> >> idea why. >> >> >> >> This simple and clear statement directly led me to the problem :) >> >> >> >> There was no cam_wen (write enable) pin on both my camera boards. The >> >> ISP on the other hand is configured by default to expect it. So I only >> >> captured images when my data lanes luckily pulled up the omap wen pin >> >> by induction. >> >> >> >> In ccdc_config_sync_if() I added: >> >> >> >> /* HACK */ >> >> printk(KERN_ALERT "Disable wen\n"); >> >> syn_mode &= ~ISPCCDC_SYN_MODE_WEN; >> >> >> >> So is this something to add to the platform data? I can prepare my >> >> very first kernel patch :) >> > >> > The WEN bit controls whether the CCDC module writes to memory or not. >> > It's not supposed to interact with the external cam_wen signal. If you >> > clear the WEN bit, the CCDC is supposed not to write data to memory at >> > all. >> > >> > What you might need to check is the EXWEN bit in the same register. It >> > controls whether the CCDC uses the cam_wen signal or not. The EXWEN bit >> > should already be set to zero by the driver though. >> > >> > Does clearing the WEN bit fix your issue ? >> >> Hi Laurent, >> >> As I remember (I currently haven't the datasheet available) the wen signal >> is an input from the camera > > That's correct. > >> and the SYN_MODE_WEN makes check this signal. > > According to the TRM, SYN_MODE_EXWEN control whether the cam_wen signal is > used or not, and SYN_MODE_WEN controls whether the CCDC captures data to > memory or not. > >> Disabling the SYN_MODE_WEN solved my problem and I can reliably read images >> with 24 MHz datarate on the parallel bus. Artefacts are gone that I had >> before with 1 MHz, too. > > If you capture data at the CCDC output, clearing SYN_MODE_WEN is supposed to > disable capture completely. Could you double-check your modifications ? Hi Laurent,
I fetched the documentation and see what you mean.Doesn't make much sense. I'll double-check soon. regards, Bastian > -- > Regards, > > Laurent Pinchart > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
