input: ti_am33x_tsc: Add DT support

This patch adds DT support to touch driver. It also provides a binding
document which is used by the MFD and IIO part of the device.
This patch also renames steps_to_configure to coordinate_readouts
because the original name misleads the purpose of the variable.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
Signed-off-by: Patil, Rachna <rachna@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

1 files changed, 44 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
new file mode 100644
index 000000000000..491c97b78384
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
@@ -0,0 +1,44 @@
+* 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,coordiante-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.
+
+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>;
+                };
+
+                adc {
+                        ti,adc-channels = <4 5 6 7>;
+                };
+        }