Hi Bastian, On Wednesday 30 March 2011 11:41:44 Bastian Hecht wrote: > 2011/3/29 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>: > > On Friday 25 March 2011 13:34:10 Bastian Hecht wrote: > >> 2011/3/24 Bastian Hecht <hechtb@xxxxxxxxxxxxxx>: > >> > 2011/3/24 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>: > >> >> On Thursday 24 March 2011 10:59:01 Bastian Hecht wrote: > >> >>> 2011/3/22 Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>: > >> >>> > 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 ? -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
