Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / devicetree / bindings / input / touchscreen / ti-tsc-adc.txt

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+* TI - TSC ADC (Touschscreen and analog digital converter)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Required properties:
+- child "tsc"
+       ti,wires: Wires refer to application modes i.e. 4/5/8 wire touchscreen
+                 support on the platform.
+       ti,x-plate-resistance: X plate resistance
+       ti,coordinate-readouts: The sequencer supports a total of 16
+                               programmable steps each step is used to
+                               read a single coordinate. A single
+                                readout is enough but multiple reads can
+                               increase the quality.
+                               A value of 5 means, 5 reads for X, 5 for
+                               Y and 2 for Z (always). This utilises 12
+                               of the 16 software steps available. The
+                               remaining 4 can be used by the ADC.
+       ti,wire-config: Different boards could have a different order for
+                       connecting wires on touchscreen. We need to provide an
+                       8 bit number where in the 1st four bits represent the
+                       analog lines and the next 4 bits represent positive/
+                       negative terminal on that input line. Notations to
+                       represent the input lines and terminals resoectively
+                       is as follows:
+                       AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
+                       XP  = 0, XN = 1, YP = 2, YN = 3.
+- child "adc"
+       ti,adc-channels: List of analog inputs available for ADC.
+                        AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
+
+Optional properties:
+- child "tsc"
+       ti,charge-delay: Length of touch screen charge delay step in terms of
+                        ADC clock cycles. Charge delay value should be large
+                        in order to avoid false pen-up events. This value
+                        effects the overall sampling speed, hence need to be
+                        kept as low as possible, while avoiding false pen-up
+                        event. Start from a lower value, say 0x400, and
+                        increase value until false pen-up events are avoided.
+                        The pen-up detection happens immediately after the
+                        charge step, so this does in fact function as a
+                        hardware knob for adjusting the amount of "settling
+                        time".
+
+Example:
+       tscadc: tscadc@44e0d000 {
+               compatible = "ti,am3359-tscadc";
+               tsc {
+                       ti,wires = <4>;
+                       ti,x-plate-resistance = <200>;
+                       ti,coordiante-readouts = <5>;
+                       ti,wire-config = <0x00 0x11 0x22 0x33>;
+                       ti,charge-delay = <0x400>;
+               };
+
+               adc {
+                       ti,adc-channels = <4 5 6 7>;
+               };
+       }