changes v4:
- spell fixes
- add more comments
- make code more readable
- move scan_buf to the priv
- use FIELD_GET to extract ADC data
- make some multi line code as one line
- do not use atomic API for trig_more_count
- fix build warning on 64bit system
- add NULL check for the devm_kasprintf()
- use return devm_iio_device_register(), without additional error
printing.
changes v3:
- different spell fixes
- add some notes about driver structure
- rename the trigger to point on the touchscreen nature of it
- rename DT binding to oversampling-ratio
- make sure we have some defaults in case no DT property is set
changes v2:
- rework and extend DT binding properties
- remove touchscreen related code from the IIO ADC driver
- make trigger be active longer then IRQ is requesting. This is needed
to get "inactive" samples
- make oversampling and settle time configurable
TI TSC2046 is a touchscreen controller based on 8 channel ADC. Since most of
this ADC based touchscreen controller share same set of challenges, it
is better keep then as simple IIO ADC devices attached to a generic
resistive-adc-touch driver.
This driver can replace drivers/input/touchscreen/ads7846.c and has
following advantages over it:
- less code to maintain
- shared code paths (resistive-adc-touch, iio-hwmon, etc)
- can be used as plain IIO ADC to investigate signaling issues or test
real capacity of the plates and attached low-pass filters
(or use the touchscreen as a microphone if you like ;) )
Oleksij Rempel (3):
dt-bindings:iio:adc: add generic settling-time-us and
oversampling-ratio channel properties
dt-bindings:iio:adc: add documentation for TI TSC2046 controller
iio: adc: add ADC driver for the TI TSC2046 controller
.../devicetree/bindings/iio/adc/adc.yaml | 9 +
.../bindings/iio/adc/ti,tsc2046.yaml | 115 +++
MAINTAINERS | 8 +
drivers/iio/adc/Kconfig | 12 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ti-tsc2046.c | 726 ++++++++++++++++++
6 files changed, 871 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
create mode 100644 drivers/iio/adc/ti-tsc2046.c
--
2.29.2
Add a binding documentation for the TI TSC2046 touchscreen controllers
ADC functionality.
Signed-off-by: Oleksij Rempel <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
---
.../bindings/iio/adc/ti,tsc2046.yaml | 115 ++++++++++++++++++
1 file changed, 115 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
diff --git a/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml b/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
new file mode 100644
index 000000000000..601d69971d84
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,tsc2046.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments TSC2046 touch screen controller.
+
+maintainers:
+ - Oleksij Rempel <[email protected]>
+
+description: |
+ TSC2046 is a touch screen controller with 8 channels ADC.
+
+properties:
+ compatible:
+ enum:
+ - ti,tsc2046e-adc
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ spi-max-frequency: true
+
+ "#io-channel-cells":
+ const: 1
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+required:
+ - compatible
+ - reg
+
+patternProperties:
+ "^channel@[0-7]$":
+ $ref: "adc.yaml"
+ type: object
+
+ properties:
+ reg:
+ description: |
+ The channel number. It can have up to 8 channels
+ items:
+ minimum: 0
+ maximum: 7
+
+ settling-time-us: true
+ oversampling-ratio: true
+
+ required:
+ - reg
+
+ additionalProperties: false
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+ spi {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ adc@0 {
+ compatible = "ti,tsc2046e-adc";
+ reg = <0>;
+ spi-max-frequency = <1000000>;
+ interrupts-extended = <&gpio3 20 IRQ_TYPE_LEVEL_LOW>;
+ #io-channel-cells = <1>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@0 {
+ reg = <0>;
+ };
+ channel@1 {
+ reg = <1>;
+ settling-time-us = <700>;
+ oversampling-ratio = <5>;
+ };
+ channel@2 {
+ reg = <2>;
+ };
+ channel@3 {
+ reg = <3>;
+ settling-time-us = <700>;
+ oversampling-ratio = <5>;
+ };
+ channel@4 {
+ reg = <4>;
+ settling-time-us = <700>;
+ oversampling-ratio = <5>;
+ };
+ channel@5 {
+ reg = <5>;
+ settling-time-us = <700>;
+ oversampling-ratio = <5>;
+ };
+ channel@6 {
+ reg = <6>;
+ };
+ channel@7 {
+ reg = <7>;
+ };
+ };
+ };
+...
--
2.29.2