[PATCH v6 03/48] dt-bindings: touchscreen: ti,am3359-tsc: New yaml description

Miquel Raynal
2021-10-15T08:15:20Z

This touchscreen controller is already described in a text file:
Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt

After introducing a proper description of the MFD, this is the second
step. The file cannot be removed yet as it also contains an ADC
description.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
.../input/touchscreen/ti,am3359-tsc.yaml | 76 +++++++++++++++++++
1 file changed, 76 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/ti,am3359-tsc.yaml

diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti,am3359-tsc.yaml b/Documentation/devicetree/bindings/input/touchscreen/ti,am3359-tsc.yaml
new file mode 100644
index 000000000000..e44cc65abc8c
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/ti,am3359-tsc.yaml
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/ti,am3359-tsc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI AM3359 Touchscreen controller
+
+maintainers:
+ - Miquel Raynal <miquel.raynal@bootlin.com>
+
+properties:
+ compatible:
+ const: ti,am3359-tsc
+
+ ti,wires:
+ description: Wires refer to application modes i.e. 4/5/8 wire touchscreen
+ support on the platform.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [4, 5, 8]
+
+ ti,x-plate-resistance:
+ description: X plate resistance
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ ti,coordinate-readouts:
+ description: 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.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 6
+
+ ti,wire-config:
+ description: Different boards could have a different order for connecting
+ wires on touchscreen. We need to provide an 8-bit number where the
+ first 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 respectively are as follows, AIN0 = 0, AIN1 = 1
+ and so on until AIN7 = 7. XP = 0, XN = 1, YP = 2, YN = 3.
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ minItems: 4
+ maxItems: 8
+
+ ti,charge-delay:
+ description: 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".
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+ - compatible
+ - ti,wires
+ - ti,x-plate-resistance
+ - ti,coordinate-readouts
+ - ti,wire-config
+
+additionalProperties: false
+
+examples:
+ - |
+ tsc {
+ compatible = "ti,am3359-tsc";
+ ti,wires = <4>;
+ ti,x-plate-resistance = <200>;
+ ti,coordinate-readouts = <5>;
+ ti,wire-config = <0x00 0x11 0x22 0x33>;
+ ti,charge-delay = <0x400>;
+ };
--
2.27.0