Input: add support for the STMicroelectronics FingerTip touchscreen

The stmfts (ST-Microelectronics FingerTip S) touchscreen device is a
capacitive multi-touch controller mainly for mobile use.  It's connected
through i2c bus at the address 0x49 and it interfaces with userspace
through input event interface.

At the current state it provides a touchscreen multitouch functionality up
to 10 fingers. Each finger is enumerated with a distinctive id (from 0 to
9).

If enabled the device can support single "touch" hovering, by providing
three coordinates, x, y and distance.

It is possible to select the touchkey functionality which provides a basic
two keys interface for "home" and "back" menu, typical in mobile phones.

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt
new file mode 100644
index 000000000000..9683595cd0f5
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.txt
@@ -0,0 +1,43 @@
+* ST-Microelectronics FingerTip touchscreen controller
+
+The ST-Microelectronics FingerTip device provides a basic touchscreen
+functionality. Along with it the user can enable the touchkey which can work as
+a basic HOME and BACK key for phones.
+
+The driver supports also hovering as an absolute single touch event with x, y, z
+coordinates.
+
+Required properties:
+- compatible            : must be "st,stmfts"
+- reg                   : I2C slave address, (e.g. 0x49)
+- interrupt-parent      : the phandle to the interrupt controller which provides
+                          the interrupt
+- interrupts            : interrupt specification
+- avdd-supply           : analogic power supply
+- vdd-supply            : power supply
+- touchscreen-size-x    : see touchscreen.txt
+- touchscreen-size-y    : see touchscreen.txt
+
+Optional properties:
+- touch-key-connected   : specifies whether the touchkey feature is connected
+- ledvdd-supply         : power supply to the touch key leds
+
+Example:
+
+i2c@00000000 {
+
+        /* ... */
+
+        touchscreen@49 {
+                compatible = "st,stmfts";
+                reg = <0x49>;
+                interrupt-parent = <&gpa1>;
+                interrupts = <1 IRQ_TYPE_NONE>;
+                touchscreen-size-x = <1599>;
+                touchscreen-size-y = <2559>;
+                touch-key-connected;
+                avdd-supply = <&ldo30_reg>;
+                vdd-supply = <&ldo31_reg>;
+                ledvdd-supply = <&ldo33_reg>;
+        };
+};