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. - 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. 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. 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��������+%������w��{.n�����{��(��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
