Re: [RFC v2 1/1] HID: User-space I/O driver support for HID subsystem

Hi Nicolas

On Wed, Mar 28, 2012 at 1:15 PM, Nicolas Pouillon [off-list ref] wr=
ote:

David,

----- Original Message -----

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+ =A0 =A0 strncpy(hid->name, ev->u.create.name, 128);
+ =A0 =A0 hid->name[127] =3D 0;
+ =A0 =A0 hid->ll_driver =3D &uhid_hid_driver;
+ =A0 =A0 hid->hid_get_raw_report =3D uhid_hid_get_raw;
+ =A0 =A0 hid->hid_output_raw_report =3D uhid_hid_output_raw;
+ =A0 =A0 hid->bus =3D ev->u.create.bus;
+ =A0 =A0 hid->vendor =3D ev->u.create.vendor;
+ =A0 =A0 hid->product =3D ev->u.create.product;
+ =A0 =A0 hid->version =3D ev->u.create.version;
+ =A0 =A0 hid->country =3D ev->u.create.country;
+ =A0 =A0 hid->phys[0] =3D 0;
+ =A0 =A0 hid->uniq[0] =3D 0;
+ =A0 =A0 hid->driver_data =3D uhid;
+ =A0 =A0 hid->dev.parent =3D uhid->parent;

Here we have to make sure that we have all required information provid=

ed

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by userspace. Anything else that HID might require to work better. Or
that BR/EDR or LE provides additionally over USB.

Beside phys and uniq I have copied all information that HIDP and
USBHID use. I haven't found any other field that could be of interest
here. We can also always add UHID_CREATE2 with additional fields to
allow further additions (or use a "size" field as you suggested
below).

HID report descriptor may reference Physical Descriptor (HID 6.2.3) and
String Descriptor entries (USB 9.6.8, HID E.11). =A0Physical Descriptor
blob could be another __user buffer + size in uhid_create_req. =A0String
descriptor should probably be an event for querying strings.

I haven't seen that hid-core uses them? I pass the report-descriptor
to hid_parse_report() and I don't see a way to pass in the phys-desc
or string-descriptors. Neither USBHID nor HIDP uses them or am I
missing something here?
Anyway, we can always add them with a UHID_CREATE_EXT or similar
command later if hid-core adds support for them.

hidraw interface also offers access to Feature Reports, adding events
to send/receive and query (kernel querying uhid client) feature reports
could be of some interest.

Yeah, I haven't implemented this (yet) and I return -EOPNOTSUPP.
However, it's on my TODO list. Thanks!

Cheers,
--
Nicolas Pouillon

Thanks
David