[fprint] Documentation for writing a new driver

[Mark Harfouche]

Hi Igor,

Thank you for your reply.

I’m confused about the parameter sent to dev_activate. Is it useful? in
uru4000.c (which seems to be the latest one written), the authors also seem
to be confused

/* FIXME: having state parameter here is kinda useless, will we ever
 * see a scenario where the parameter is useful so early on in the activation
 * process? asynchronity means that it'll only be used in a later function
 * call. */static int dev_activate(struct fp_img_dev *dev, enum
fp_imgdev_state state)
{

Thanks,

Mark

On Fri, Mar 9, 2018 at 10:43 AM, Igor Filatov <ia.filatov at gmail.com> wrote:

Hi Mark,
>
> There are no high-level docs, unfortunately. There's some valuable info in
> comments in drv.c, sync.c, async.c, img.c etc. but it only covers specific
> parts, not how they should interact.
>
> There are 6 drivers for press-type sensors: aes3500.c, aes4000.c,
> fdu2000.c, upektc.c, uru4000.c, vcom5s.c. But there isn't much difference
> between press and swipe drivers. FP_SCAN_TYPE_* is used to determine which
> messages to show ("please touch the sensor" vs. "please swipe..."), and I
> think that's it. Besides that, all drivers essentially do the same thing:
> obtain the fingerprint image and submit it. You can use any driver as a
> reference.
>
>
>
> On Fri, Mar 9, 2018 at 7:50 PM Mark Harfouche <mark.harfouche at gmail.com>
> wrote:
>
>> Hello all,
>>
>> I would like to develop a driver for the Validity 0091 sensor available
>> on the Dell XPS13/15 9X60.
>>
>> I would say I have the driver reverse engineered to 95% (There might be a
>> few things I still don’t understand from the internal state machine).
>> https://github.com/hmaarrfk/Validity91
>> WIP: https://github.com/freedesktop/libfprint
>>
>> I found the libfprint source, can compile it, and started creating my own
>> driver.
>>
>> However, I am confused about the internal workings of libfprint and the
>> functions I need to define.
>> I tried to follow examples that were included, but it seemed that they
>> were mostly “swipe”‘ sensors, and not capacitive style sensor.
>> Is there any good documentation about the state machines I need to
>> implement with regards to the functions
>>
>>     .open = dev_open,
>>     .close = dev_close,
>>     .activate = dev_activate,
>>     .deactivate = dev_deactivate,
>>     .change_state = dev_change_state,
>>
>> Thanks,
>>
>> Mark
>> ​
>> _______________________________________________
>> fprint mailing list
>> fprint at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/fprint
>>
> ​
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/fprint/attachments/20180309/7937430e/attachment-0001.html>