1 Device tree bindings for TI's ADS7843, ADS7845, ADS7846, ADS7873, TSC2046
2 SPI driven touch screen controllers.
4 The node for this driver must be a child node of a SPI controller, hence
5 all mandatory properties described in
7 Documentation/devicetree/bindings/spi/spi-bus.txt
11 Additional required properties:
13 compatible Must be one of the following, depending on the
22 interrupts An interrupt node describing the IRQ line the chip's
23 !PENIRQ pin is connected to.
24 vcc-supply A regulator node for the supply voltage.
29 ti,vref-delay-usecs vref supply delay in usecs, 0 for
31 ti,vref-mv The VREF voltage, in millivolts (u16).
32 ti,keep-vref-on set to keep vref on for differential
34 ti,swap-xy swap x and y axis
35 ti,settle-delay-usec Settling time of the analog signals;
36 a function of Vcc and the capacitance
37 on the X/Y drivers. If set to non-zero,
38 two samples are taken with settle_delay
39 us apart, and the second one is used.
40 ~150 uSec with 0.01uF caps (u16).
41 ti,penirq-recheck-delay-usecs If set to non-zero, after samples are
42 taken this delay is applied and penirq
43 is rechecked, to help avoid false
44 events. This value is affected by the
45 material used to build the touch layer
47 ti,x-plate-ohms Resistance of the X-plate,
49 ti,y-plate-ohms Resistance of the Y-plate,
51 ti,x-min Minimum value on the X axis (u16).
52 ti,y-min Minimum value on the Y axis (u16).
53 ti,x-max Maximum value on the X axis (u16).
54 ti,y-max Minimum value on the Y axis (u16).
55 ti,pressure-min Minimum reported pressure value
57 ti,pressure-max Maximum reported pressure value (u16).
58 ti,debounce-max Max number of additional readings per
60 ti,debounce-tol Tolerance used for filtering (u16).
61 ti,debounce-rep Additional consecutive good readings
62 required after the first two (u16).
63 ti,pendown-gpio-debounce Platform specific debounce time for the
65 pendown-gpio GPIO handle describing the pin the !PENIRQ
67 linux,wakeup use any event on touchscreen as wakeup event.
70 Example for a TSC2046 chip connected to an McSPI controller of an OMAP SoC::
75 compatible = "ti,tsc2046";
76 interrupt-parent = <&gpio1>;
77 interrupts = <8 0>; /* BOOT6 / GPIO 8 */
78 spi-max-frequency = <1000000>;
79 pendown-gpio = <&gpio1 8 0>;
80 vcc-supply = <®_vcc3>;
82 ti,x-min = /bits/ 16 <0>;
83 ti,x-max = /bits/ 16 <8000>;
84 ti,y-min = /bits/ 16 <0>;
85 ti,y-max = /bits/ 16 <4800>;
86 ti,x-plate-ohms = /bits/ 16 <40>;
87 ti,pressure-max = /bits/ 16 <255>;