1* TI - TSC ADC (Touschscreen and analog digital converter)
2~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3
4Required properties:
5- child "tsc"
6	ti,wires: Wires refer to application modes i.e. 4/5/8 wire touchscreen
7		  support on the platform.
8	ti,x-plate-resistance: X plate resistance
9	ti,coordinate-readouts: The sequencer supports a total of 16
10				programmable steps each step is used to
11				read a single coordinate. A single
12                                readout is enough but multiple reads can
13				increase the quality.
14				A value of 5 means, 5 reads for X, 5 for
15				Y and 2 for Z (always). This utilises 12
16				of the 16 software steps available. The
17				remaining 4 can be used by the ADC.
18	ti,wire-config: Different boards could have a different order for
19			connecting wires on touchscreen. We need to provide an
20			8 bit number where in the 1st four bits represent the
21			analog lines and the next 4 bits represent positive/
22			negative terminal on that input line. Notations to
23			represent the input lines and terminals resoectively
24			is as follows:
25			AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
26			XP  = 0, XN = 1, YP = 2, YN = 3.
27- child "adc"
28	ti,adc-channels: List of analog inputs available for ADC.
29			 AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
30
31Optional properties:
32- child "tsc"
33	ti,charge-delay: Length of touch screen charge delay step in terms of
34			 ADC clock cycles. Charge delay value should be large
35			 in order to avoid false pen-up events. This value
36			 effects the overall sampling speed, hence need to be
37			 kept as low as possible, while avoiding false pen-up
38			 event. Start from a lower value, say 0x400, and
39			 increase value until false pen-up events are avoided.
40			 The pen-up detection happens immediately after the
41			 charge step, so this does in fact function as a
42			 hardware knob for adjusting the amount of "settling
43			 time".
44
45Example:
46	tscadc: tscadc@44e0d000 {
47		compatible = "ti,am3359-tscadc";
48		tsc {
49			ti,wires = <4>;
50			ti,x-plate-resistance = <200>;
51			ti,coordiante-readouts = <5>;
52			ti,wire-config = <0x00 0x11 0x22 0x33>;
53			ti,charge-delay = <0x400>;
54		};
55
56		adc {
57			ti,adc-channels = <4 5 6 7>;
58		};
59	}
60