On Fri, Oct 28, 2016 at 2:53 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > Hi Matt, > > On 28/10/16 22:14, Matt Ranostay wrote: >> >> So want to toss a few thoughts on adding support for thermopile >> devices (could be used for FLIR Lepton as well) that output pixel >> data. >> These typically aren't DMA'able devices since they are low speed >> (partly to limiting the functionality to be in compliance with ITAR) >> and data is piped over i2c/spi. >> >> My question is that there doesn't seem to be an other driver that >> polls frames off of a device and pushes it to the video buffer, and >> wanted to be sure that this doesn't currently exist somewhere. > > > Not anymore, but if you go back to kernel 3.6 then you'll find this driver: > > drivers/media/video/bw-qcam.c > > It was for a grayscale parallel port webcam (which explains why it was > removed in 3.7 :-) ), and it used polling to get the pixels. Yikes parallel port, but I'll take a look at that for some reference :) > >> Also more importantly does the mailing list thinks it belongs in v4l2? > > > I think it fits. It's a sensor, just with a very small resolution and > infrared > instead of visible light. > >> We already came up the opinion on the IIO list that it doesn't belong >> in that subsystem since pushing raw pixel data to a buffer is a bit >> hacky. Also could be generically written with regmap so other devices >> (namely FLIR Lepton) could be easily supported. >> >> Need some input for the video pixel data types, which the device we >> are using (see datasheet links below) is outputting pixel data in >> little endian 16-bit of which a 12-bits signed value is used. Does it >> make sense to do some basic processing on the data since greyscale is >> going to look weird with temperatures under 0C degrees? Namely a cold >> object is going to be brighter than the hottest object it could read. > > >> Or should a new V4L2_PIX_FMT_* be defined and processing done in >> software? > > > I would recommend that. It's no big deal, as long as the new format is > documented. > >> Another issue is how to report the scaling value of 0.25 C >> for each LSB of the pixels to the respecting recording application. > > > Probably through a read-only control, but I'm not sure. > > Regards, > > Hans > >> >> Datasheet: >> http://media.digikey.com/pdf/Data%20Sheets/Panasonic%20Sensors%20PDFs/Grid-EYE_AMG88.pdf >> Datasheet: >> https://eewiki.net/download/attachments/13599167/Grid-EYE%20SPECIFICATIONS%28Reference%29.pdf?version=1&modificationDate=1380660426690&api=v2 >> >> Thanks, >> >> Matt >> -- >> 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 >> > -- 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
