On Vi, 2014-12-26 at 11:13 +0000, Jonathan Cameron wrote: > 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. Any thoughts on this from the v4l community? Thanks, Teodora > > > >> > >> 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 > ��.n��������+%������w��{.n�����{��g����^n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
