Hi Rob,
On 01-08-16 18:54, Rob Herring wrote:
On Sun, Jul 31, 2016 at 05:23:07PM +0200, Hans de Goede wrote:
Some touchscreens extend over the display they cover and have a number
of capacative softbuttons outside of the display the cover.
With some hardware these softbuttons simply report touches with
coordinates outside of the normal coordinate space for touches on the
display.
This commit adds a devicetree binding for describing such buttons in
devicetree and a bunch of helper functions to easily add support for
these to existing touchscreen drivers.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
.../bindings/input/touchscreen/softbuttons.txt | 58 +++++++++
drivers/input/touchscreen/Makefile | 2 +-
drivers/input/touchscreen/softbuttons.c | 145 +++++++++++++++++++++
include/linux/input/touchscreen.h | 9 ++
4 files changed, 213 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/softbuttons.txt
create mode 100644 drivers/input/touchscreen/softbuttons.c
diff --git a/Documentation/devicetree/bindings/input/touchscreen/softbuttons.txt b/Documentation/devicetree/bindings/input/touchscreen/softbuttons.txt
new file mode 100644
index 0000000..3eb6f4c
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/softbuttons.txt
@@ -0,0 +1,58 @@
+General Touchscreen Softbutton Properties:
+
+Some touchscreens extend over the display they cover and have a number
+of capacative softbuttons outside of the display the cover.
+
+Some of these softbuttons simply report touches with coordinates outside of
+the normal coordinate space for touches on the display. This binding is for
+describing such buttons in devicetree.
+
+Each softkey is represented as a sub-node of the touchscreen node.
+
+Required subnode-properties:
+ - label : Descriptive name of the key.
+ - linux,code : Keycode to emit.
+ - softbutton-min-x : X start of the area the softbutton area covers
+ - softbutton-max-x : X end of the area the softbutton area covers
+ - softbutton-min-y : Y start of the area the softbutton area covers
+ - softbutton-max-y : Y end of the area the softbutton area covers
This generally looks fine to me, but I am wondering one thing. If the
buttons are located at the origin of an axis, can we handle that case? I
don't think you can unless you assume softbutton-max-? is 0 for the
touchscreen. To put it another way, you have a gap from 1024 to 1084
which you can't express for buttons at the origin unless you do negative
numbers.
Actually for the touchscreen I'm working on:
https://content.hwigroup.net/images/products_xl/157078/dserve-dsrv-9703c.jpg
The buttons are past the display edge which corresponds to x coordinate 0,
so they should logically send negative coordinates but the "firmware" (which
I believe is more config / calibration data) maps them to coordinates above
1024, so logically across the other edge. But I can envision some other
hardware doing this differently. I suggest we deal with this when we need too,
likely we just need to add a note that the dt min/max values should be interpreted
as a s32 rather then an u32, I can do that now if you want.
Regards,
Hans
Rob
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