Thread (25 messages) 25 messages, 4 authors, 2016-11-11

Re: [PATCH v4 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation

From: Rob Herring <hidden>
Date: 2016-10-18 16:23:19
Also in: linux-iio, linux-input, linux-omap, lkml

On Mon, Oct 17, 2016 at 8:57 AM, H. Nikolaus Schaller [off-list ref] wrote:
commit b98abe52fa8e ("Input: add common DT binding for touchscreens")
introduced common DT bindings for touchscreens [1] and a helper function to
parse the DT.

commit ed7c9870c9bc ("Input: of_touchscreen - add support for inverted / swapped axes")
added another helper for parsing axis inversion and swapping
and applying them to x and y coordinates.

Both helpers have been integrated to accommodate any orientation of the
touch panel in relation to the LCD.
Please add the explanation of why this is a compatible change here.
A new feature is to introduce scaling the min/max ADC values to the screen
size.
Sounds like a separate change.
quoted hunk ↗ jump to hunk
This makes it possible to pre-calibrate the touch so that is (almost)
exactly matches the LCD pixel coordinates it is glued onto. This allows to
well enough operate the touch before a user space calibration step can
improve the precision.

Finally, calculate_pressure has been renamed to calculate_resistance
because that is what it is doing.

[1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

Signed-off-by: H. Nikolaus Schaller <redacted>
---
 .../bindings/input/touchscreen/tsc2007.txt         |  20 ++--
 drivers/input/touchscreen/tsc2007.c                | 120 +++++++++++++++++----
 include/linux/i2c/tsc2007.h                        |   8 ++
 3 files changed, 118 insertions(+), 30 deletions(-)
diff --git a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
index ec365e1..6e9fd55 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/tsc2007.txt
@@ -6,6 +6,7 @@ Required properties:
 - ti,x-plate-ohms: X-plate resistance in ohms.

 Optional properties:
+- generic touch screen properties: see touchscreen binding [2].
 - gpios: the interrupt gpio the chip is connected to (trough the penirq pin).
   The penirq pin goes to low when the panel is touched.
   (see GPIO binding[1] for more details).
@@ -13,17 +14,20 @@ Optional properties:
   (see interrupt binding[0]).
 - interrupts: (gpio) interrupt to which the chip is connected
   (see interrupt binding[0]).
-- ti,max-rt: maximum pressure.
-- ti,fuzzx: specifies the absolute input fuzz x value.
-  If set, it will permit noise in the data up to +- the value given to the fuzz
-  parameter, that is used to filter noise from the event stream.
-- ti,fuzzy: specifies the absolute input fuzz y value.
-- ti,fuzzz: specifies the absolute input fuzz z value.
+- ti,max-rt: maximum pressure resistance above which samples are ignored
+  (default: 4095).
+- ti,report-resistance: report resistance (no pressure = max_rt) instead
+  of pressure (no pressure = 0).
+- ti,min-x: minimum value reported by X axis ADC (default 0).
+- ti,max-x: maximum value reported by X axis ADC (default 4095).
+- ti,min-y: minimum value reported by Y axis ADC (default 0).
+- ti,max-y: maximum value reported by Y axis ADC (default 4095).
I thought these were going to be common? I think they should be.

Rob
quoted hunk ↗ jump to hunk
 - ti,poll-period: how much time to wait (in milliseconds) before reading again the
-  values from the tsc2007.
+  values from the tsc2007 (default 1).

 [0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
 [1]: Documentation/devicetree/bindings/gpio/gpio.txt
+[2]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt

 Example:
        &i2c1 {
@@ -35,6 +39,8 @@ Example:
                        interrupts = <0x0 0x8>;
                        gpios = <&gpio4 0 0>;
                        ti,x-plate-ohms = <180>;
+                       touchscreen-size-x = <640>;
+                       touchscreen-size-y = <480>;
                };

                /* ... */
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