[meta-intel] [PATCH] formfactor: detect USB HID keyboard and touch screen

[Saul Wold]

On Fri, 2016-04-15 at 13:59 -0700, Jianxun Zhang wrote:
> The new machconfig probes USB keyboard and touch screen, and
> then sets HAVE_* variables according to detection.
> 
> Detectable devices:
> USB HID keyboards (Generic Desktop)
> USB HID touch screens (Digitizer)
> 
> Note:
> The intention is to have a way to provide initial formfactor
> settings in a boot procedure. That means supported keyboard
> and touch screen must be connected before machconfig runs.
> Any new connection or disconnection won't be detected until
> machconfig is executed again.
> 
> Limitation:
> There could be some USB HID devices presents more than one
> usage in a single descriptor. We will add support once such
> device emerges.
> 
> Some platforms may have _virtual_ devices provided by BIOS.
> It will cause false detection when they are presented as
> types we supported. We can add black list logic when it
> becomes a big concern.
> 
> Fixes [YOCTO #9205]
> 
> Signed-off-by: Jianxun Zhang <jianxun.zhang at linux.intel.com>

> ---
>  .../recipes-bsp/formfactor/formfactor/machconfig   | 37
> ++++++++++++++++++++++
>  .../recipes-bsp/formfactor/formfactor_0.0.bbappend |  1 +
>  2 files changed, 38 insertions(+)
>  create mode 100644 common/recipes-
> bsp/formfactor/formfactor/machconfig
>  create mode 100644 common/recipes-
> bsp/formfactor/formfactor_0.0.bbappend
> 
> diff --git a/common/recipes-bsp/formfactor/formfactor/machconfig
> b/common/recipes-bsp/formfactor/formfactor/machconfig
> new file mode 100644
> index 0000000..d2f12b2
> --- /dev/null
> +++ b/common/recipes-bsp/formfactor/formfactor/machconfig
> @@ -0,0 +1,37 @@
> +# Note: super user permission is required to run usbhid-dump
> +# successfully.
> +
> +# HEX keys are according to USB HID spec and USB HID usage table
> +# We could add more keys as needed in the future.
> +
> +# checker for generic USB HID keyboard
> +USBHID_KBD_CMD="grep -E '^ 05 01 09 06'"
> +
> +# checker for touch screen
> +USBHID_TS_CMD="grep -E '^ 05 0D 09 04'"
> +
> +# It may not be very accurate. Here we only look for first two lines
> +# of a descriptor section. Example:
> +#
> +# 001:003:000:DESCRIPTOR         1460501386.337809
> +#  05 01 09 02 A1 01 09 01 A1 00 05 09 19 01 29 03
> +#  15 00 25 01 95 03 75 01 81 02 .. .. .. .. .. ..
> +#  .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
> +#
> +# By doing so we elimiate false matches when HEX keys are in the
> lines
> +# in the middle of whole descriptor section.
> +
> +USBHID_DUMP_OUTPUT=$(sudo usbhid-dump -e descriptor|grep -A1
> DESCRIPTOR)
The sudo here is redundant since this script will run as root during
startup.

Also you should check if usbhid-dump exists before calling it and set
reasonable defaults for HAVE_KEYBOARD and TOUCHSCREEN and then exit.

Sau!

> +
> +if echo "$USBHID_DUMP_OUTPUT"|eval $USBHID_TS_CMD &>/dev/null; then
> +    HAVE_TOUCHSCREEN=1
> +fi
> +
> +if echo "$USBHID_DUMP_OUTPUT"|eval $USBHID_KBD_CMD &>/dev/null; then
> +    HAVE_KEYBOARD=1
> +else
> +    # config script in OE will set HAVE_KEYBOARD=1
> +    # if we don't set any value. We have to explicitly
> +    # tell it when keyboard is not detected.
> +    HAVE_KEYBOARD=0
> +fi
> diff --git a/common/recipes-bsp/formfactor/formfactor_0.0.bbappend
> b/common/recipes-bsp/formfactor/formfactor_0.0.bbappend
> new file mode 100644
> index 0000000..72d991c
> --- /dev/null
> +++ b/common/recipes-bsp/formfactor/formfactor_0.0.bbappend
> @@ -0,0 +1 @@
> +FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
> -- 
> 1.9.1
>