On 18/12/14 16:51, Lars-Peter Clausen wrote: > Adding V4L folks to Cc for more input. Thanks Lars - we definitely would need the v4l guys to agree to a driver like this going in IIO. (not that I'm convinced it should!) > > On 12/08/2014 03:10 PM, Baluta, Teodora wrote: >> Hello, >> >> On Vi, 2014-12-05 at 02:15 +0000, Jonathan Cameron wrote: >>> On 04/12/14 13:00, Teodora Baluta wrote: >>>> This patchset adds support for fingerprint sensors through the IIO interface. >>>> This way userspace applications collect information in a uniform way. All >>>> processing would be done in the upper layers as suggested in [0]. >>>> >>>> In order to test out this proposal, a minimal implementation for UPEK's >>>> TouchChip Fingerprint Sensor via USB is also available. Although there is an >>>> existing implementation in userspace for USB fingerprint devices, including this >>>> particular device, the driver represents a proof of concept of how fingerprint >>>> sensors could be integrated in the IIO framework regardless of the used bus. For >>>> lower power requirements, the SPI bus is preferred and a kernel driver >>>> implementation makes more sense. >>> >>> So why not v4l? These are effectively image sensors.. >> >> Well, here's why I don't think v4l would be the best option: >> >> - an image scanner could be implemented in the v4l subsystem, but it >> seems far more complicated for a simple fingerprint scanner - it usually >> has drivers for webcams, TVs or video streaming devices. The v4l >> subsystem (with all its support for colorspace, decoders, image >> compression, frame control) seems a bit of an overkill for a very >> straightforward fingerprint imaging sensor. Whilst those are there, I would doubt the irrelevant bits would put much burden on a fingerprint scanning driver. Been a while since I did anything in that area though so I could be wrong! >> >> - a fingerprint device could also send out a processed information, not >> just the image of a fingerprint. This means that the processing is done >> in hardware - the UPEK TouchStrip chipset in libfprint has this behavior >> (see [0]). So, the IIO framework would support a uniform way of handling >> fingerprint devices that either do processing in software or in >> hardware. This is more interesting, but does that map well to IIO style channels anyway? If not we are going to end up with a whole new interface which ever subsystem is used for the image side of things. >> >> The way I see it now, for processed fingerprint information, an IIO >> device could have an IIO_FINGERPRINT channel with a modifier and only >> the sensitivity threshold attribute set. We would also need two >> triggers: one for enrollment and one for the verification mode to >> control the device from a userspace application. Sure - what you proposed would work. The question is whether it is the best way to do it. >> >> Thanks, >> Teodora >> >> [0] http://www.freedesktop.org/wiki/Software/fprint/libfprint/upekts/ >> >> >>>> >>>> A sysfs trigger is enabled and the device starts scanning. As soon as an image >>>> is available it is written in the character device /dev/iio:deviceX. >>>> >>>> Userspace applications will be able to calculate the expected image size using >>>> the fingerprint attributes height, width and bit depth. Other attributes >>>> introduced for the fingerprint channel in IIO represent information that aids in >>>> the fingerprint image processing. Besides these, the proposed interface offers >>>> userspace a way to read a feedback after a scan (like the swipe was too slow or >>>> too fast) through a modified fingerprint_status channel. >>>> >>>> [0] http://www.spinics.net/lists/linux-iio/msg11463.html >>>> >>>> Teodora Baluta (3): >>>> iio: core: add support for fingerprint devices >>>> iio: core: change channel's storagebits/realbits to u32 >>>> iio: fingerprint: add fingerprint sensor via USB >>>> >>>> Documentation/ABI/testing/sysfs-bus-iio | 51 +++ >>>> drivers/iio/Kconfig | 1 + >>>> drivers/iio/Makefile | 1 + >>>> drivers/iio/fingerprint/Kconfig | 15 + >>>> drivers/iio/fingerprint/Makefile | 5 + >>>> drivers/iio/fingerprint/fp_tc.c | 162 +++++++++ >>>> drivers/iio/fingerprint/fp_tc.h | 22 ++ >>>> drivers/iio/fingerprint/fp_tc_usb.c | 618 ++++++++++++++++++++++++++++++++ >>>> drivers/iio/fingerprint/fp_tc_usb.h | 144 ++++++++ >>>> drivers/iio/industrialio-core.c | 9 + >>>> include/linux/iio/iio.h | 11 +- >>>> include/linux/iio/types.h | 10 + >>>> 12 files changed, 1047 insertions(+), 2 deletions(-) >>>> create mode 100644 drivers/iio/fingerprint/Kconfig >>>> create mode 100644 drivers/iio/fingerprint/Makefile >>>> create mode 100644 drivers/iio/fingerprint/fp_tc.c >>>> create mode 100644 drivers/iio/fingerprint/fp_tc.h >>>> create mode 100644 drivers/iio/fingerprint/fp_tc_usb.c >>>> create mode 100644 drivers/iio/fingerprint/fp_tc_usb.h >>>> >>> >> >> N�����r��y���b�X��ǧv�^�){.n�+����{��*"��^n�r���z���h����&�� �G���h�(�階�ݢj"���m�����z�ޖ���f���h���~�mml== >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" 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-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
