changes v1:
- add yaml conversion patch to this series
- reword commit message for the last patch
- fix possible overflow on the buffer dispatcher
Oleksij Rempel (4):
dt-bindings: touchscreen: Convert resistive-adc-touch binding to json
schema
dt-bindings: touchscreen: add touchscreen-x/y-plate-ohms property
dt-bindings: touchscreen: resistive-adc-touch: add support for z1 and
z2 channels
Input: resistive-adc-touch: add support for z1 and z2 channels
.../input/touchscreen/resistive-adc-touch.txt | 33 ----
.../touchscreen/resistive-adc-touch.yaml | 70 +++++++++
.../input/touchscreen/touchscreen.yaml | 6 +
.../input/touchscreen/resistive-adc-touch.c | 141 ++++++++++++++++--
4 files changed, 204 insertions(+), 46 deletions(-)
delete mode 100644 Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
--
2.29.2
Te calculate the pressure on a restrictive touchscreen we need need to
know resistance at least of X plate. Some calculations need to use both
X and Y values.
So, add generic properties which can be used by all drivers
Signed-off-by: Oleksij Rempel <[email protected]>
---
.../devicetree/bindings/input/touchscreen/touchscreen.yaml | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
index 046ace461cc9..4b5b212c772c 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
@@ -74,6 +74,12 @@ properties:
touchscreen-y-mm:
description: vertical length in mm of the touchscreen
+ touchscreen-x-plate-ohms:
+ description: Resistance of the X-plate in Ohms
+
+ touchscreen-y-plate-ohms:
+ description: Resistance of the Y-plate in Ohms
+
dependencies:
touchscreen-size-x: [ touchscreen-size-y ]
touchscreen-size-y: [ touchscreen-size-x ]
--
2.29.2
This patch adds support for the z1 and z2 channels. These are used to
calculate the applied pressure. As there is no common order of the
individual channels of a resistive touch ADC, support for
io-channel-names is added (although the DT bindings stated the
driver already supports these).
Signed-off-by: Oleksij Rempel <[email protected]>
---
.../input/touchscreen/resistive-adc-touch.c | 141 ++++++++++++++++--
1 file changed, 128 insertions(+), 13 deletions(-)
diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c
index e50af30183f4..470b95ed3569 100644
--- a/drivers/input/touchscreen/resistive-adc-touch.c
+++ b/drivers/input/touchscreen/resistive-adc-touch.c
@@ -20,7 +20,18 @@
#define DRIVER_NAME "resistive-adc-touch"
#define GRTS_DEFAULT_PRESSURE_MIN 50000
+#define GRTS_DEFAULT_PRESSURE_MAX 65535
#define GRTS_MAX_POS_MASK GENMASK(11, 0)
+#define GRTS_MAX_CHANNELS 4
+
+enum grts_ch_type {
+ GRTS_CH_NONE = 0,
+ GRTS_CH_X,
+ GRTS_CH_Y,
+ GRTS_CH_PRESSURE,
+ GRTS_CH_Z1,
+ GRTS_CH_Z2,
+};
/**
* struct grts_state - generic resistive touch screen information struct
@@ -33,24 +44,61 @@
*/
struct grts_state {
u32 pressure_min;
+ u32 x_plate_ohms;
bool pressure;
struct iio_channel *iio_chans;
struct iio_cb_buffer *iio_cb;
struct input_dev *input;
struct touchscreen_properties prop;
+ u8 ch[GRTS_MAX_CHANNELS];
};
static int grts_cb(const void *data, void *private)
{
const u16 *touch_info = data;
struct grts_state *st = private;
- unsigned int x, y, press = 0x0;
+ unsigned int x, y, press = 0, z1 = 0, z2;
+ unsigned int Rt, i;
+
+ for (i = 0; i < ARRAY_SIZE(st->ch) && st->ch[i] != GRTS_CH_NONE; i++) {
+ switch (st->ch[i]) {
+ case GRTS_CH_X:
+ x = touch_info[i];
+ break;
+ case GRTS_CH_Y:
+ y = touch_info[i];
+ break;
+ case GRTS_CH_PRESSURE:
+ press = touch_info[i];
+ break;
+ case GRTS_CH_Z1:
+ z1 = touch_info[i];
+ break;
+ case GRTS_CH_Z2:
+ z2 = touch_info[i];
+ break;
+ case GRTS_CH_NONE:
+ break;
+ }
+ }
- /* channel data coming in buffer in the order below */
- x = touch_info[0];
- y = touch_info[1];
- if (st->pressure)
- press = touch_info[2];
+ if (z1) {
+ Rt = z2;
+ Rt -= z1;
+ Rt *= st->x_plate_ohms;
+ Rt = DIV_ROUND_CLOSEST(Rt, 16);
+ Rt *= x;
+ Rt /= z1;
+ Rt = DIV_ROUND_CLOSEST(Rt, 256);
+ /*
+ * On increased pressure the resistance (Rt) is decreasing
+ * so, convert values to make it looks as real pressure.
+ */
+ if (Rt < GRTS_DEFAULT_PRESSURE_MAX)
+ press = GRTS_DEFAULT_PRESSURE_MAX - Rt;
+ else
+ press = 0;
+ }
if ((!x && !y) || (st->pressure && (press < st->pressure_min))) {
/* report end of touch */
@@ -94,6 +142,72 @@ static void grts_disable(void *data)
iio_channel_release_all_cb(data);
}
+static int grts_get_properties(struct grts_state *st, struct device *dev)
+{
+ int idx, error;
+
+ idx = device_property_match_string(dev, "io-channel-names", "x");
+ if (idx < 0)
+ return idx;
+
+ if (idx >= ARRAY_SIZE(st->ch))
+ return -EOVERFLOW;
+
+ st->ch[idx] = GRTS_CH_X;
+
+ idx = device_property_match_string(dev, "io-channel-names", "y");
+ if (idx < 0)
+ return idx;
+
+ if (idx >= ARRAY_SIZE(st->ch))
+ return -EOVERFLOW;
+
+ st->ch[idx] = GRTS_CH_Y;
+
+ /* pressure is optional */
+ idx = device_property_match_string(dev, "io-channel-names", "pressure");
+ if (idx >= 0) {
+ if (idx >= ARRAY_SIZE(st->ch))
+ return -EOVERFLOW;
+
+ st->ch[idx] = GRTS_CH_PRESSURE;
+ st->pressure = true;
+
+ return 0;
+ }
+
+ /* if no pressure is defined, try optional z1 + z2 */
+ idx = device_property_match_string(dev, "io-channel-names", "z1");
+ if (idx < 0)
+ return 0;
+
+ if (idx >= ARRAY_SIZE(st->ch))
+ return -EOVERFLOW;
+
+ st->ch[idx] = GRTS_CH_Z1;
+
+ /* if z1 is provided z2 is not optional */
+ idx = device_property_match_string(dev, "io-channel-names", "z2");
+ if (idx < 0)
+ return idx;
+
+ if (idx >= ARRAY_SIZE(st->ch))
+ return -EOVERFLOW;
+
+ st->ch[idx] = GRTS_CH_Z2;
+ st->pressure = true;
+
+ error = device_property_read_u32(dev,
+ "touchscreen-x-plate-ohms",
+ &st->x_plate_ohms);
+ if (error) {
+ dev_err(dev, "can't get touchscreen-x-plate-ohms property\n");
+ return error;
+ }
+
+ return 0;
+}
+
static int grts_probe(struct platform_device *pdev)
{
struct grts_state *st;
@@ -115,12 +229,13 @@ static int grts_probe(struct platform_device *pdev)
return error;
}
- chan = &st->iio_chans[0];
- st->pressure = false;
- while (chan && chan->indio_dev) {
- if (!strcmp(chan->channel->datasheet_name, "pressure"))
- st->pressure = true;
- chan++;
+ if (!device_property_present(dev, "io-channel-names"))
+ return -ENODEV;
+
+ error = grts_get_properties(st, dev);
+ if (error) {
+ dev_err(dev, "Failed to parse properties\n");
+ return error;
}
if (st->pressure) {
@@ -148,7 +263,7 @@ static int grts_probe(struct platform_device *pdev)
input_set_abs_params(input, ABS_Y, 0, GRTS_MAX_POS_MASK - 1, 0, 0);
if (st->pressure)
input_set_abs_params(input, ABS_PRESSURE, st->pressure_min,
- 0xffff, 0, 0);
+ GRTS_DEFAULT_PRESSURE_MAX, 0, 0);
input_set_capability(input, EV_KEY, BTN_TOUCH);
--
2.29.2
Convert the resistive-adc-touch binding to DT schema format using json-schema.
Signed-off-by: Oleksij Rempel <[email protected]>
---
.../input/touchscreen/resistive-adc-touch.txt | 33 ----------
.../touchscreen/resistive-adc-touch.yaml | 61 +++++++++++++++++++
2 files changed, 61 insertions(+), 33 deletions(-)
delete mode 100644 Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
diff --git a/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt b/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt
deleted file mode 100644
index af5223bb5bdd..000000000000
--- a/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.txt
+++ /dev/null
@@ -1,33 +0,0 @@
-Generic resistive touchscreen ADC
-
-Required properties:
-
- - compatible: must be "resistive-adc-touch"
-The device must be connected to an ADC device that provides channels for
-position measurement and optional pressure.
-Refer to
-https://github.com/devicetree-org/dt-schema/blob/master/schemas/iio/iio-consumer.yaml
-for details
-
- - iio-channels: must have at least two channels connected to an ADC device.
-These should correspond to the channels exposed by the ADC device and should
-have the right index as the ADC device registers them. These channels
-represent the relative position on the "x" and "y" axes.
- - iio-channel-names: must have all the channels' names. Mandatory channels
-are "x" and "y".
-
-Optional properties:
- - iio-channels: The third channel named "pressure" is optional and can be
-used if the ADC device also measures pressure besides position.
-If this channel is missing, pressure will be ignored and the touchscreen
-will only report position.
- - iio-channel-names: optional channel named "pressure".
-
-Example:
-
- resistive_touch: resistive_touch {
- compatible = "resistive-adc-touch";
- touchscreen-min-pressure = <50000>;
- io-channels = <&adc 24>, <&adc 25>, <&adc 26>;
- io-channel-names = "x", "y", "pressure";
- };
diff --git a/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml b/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
new file mode 100644
index 000000000000..53df21a6589e
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/resistive-adc-touch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic resistive touchscreen ADC
+
+maintainers:
+ - Oleksij Rempel <[email protected]>
+
+description: |
+ Generic ADC based resistive touchscreen controller
+ The device must be connected to an ADC device that provides channels for
+ position measurement and optional pressure.
+
+allOf:
+ - $ref: touchscreen.yaml#
+
+properties:
+ compatible:
+ const: resistive-adc-touch
+
+ io-channels:
+ minItems: 2
+ maxItems: 3
+ items:
+ - description: x
+ - description: y
+ - description: pressure (optional)
+
+ io-channel-names:
+ items:
+ - const: x
+ - const: y
+ - const: pressure
+
+ touchscreen-size-x: true
+ touchscreen-size-y: true
+ touchscreen-fuzz-x: true
+ touchscreen-fuzz-y: true
+ touchscreen-inverted-x: true
+ touchscreen-inverted-y: true
+ touchscreen-swapped-x-y: true
+ touchscreen-min-pressure: true
+
+additionalProperties: false
+
+required:
+ - compatible
+ - io-channels
+ - io-channel-names
+
+examples:
+ - |
+ resistive_touch {
+ compatible = "resistive-adc-touch";
+ touchscreen-min-pressure = <50000>;
+ io-channels = <&adc 24>, <&adc 25>, <&adc 26>;
+ io-channel-names = "x", "y", "pressure";
+ };
--
2.29.2
For pressure calculation based on plates resistance we need some additional
properties:
- z1 and z2 channels with additional measurements between plates
- actual resistance of the touchscreen. Currently we use only
X-resistance.
Signed-off-by: Oleksij Rempel <[email protected]>
---
.../bindings/input/touchscreen/resistive-adc-touch.yaml | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml b/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
index 53df21a6589e..538c3b1ef1e1 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
@@ -43,6 +43,7 @@ properties:
touchscreen-inverted-y: true
touchscreen-swapped-x-y: true
touchscreen-min-pressure: true
+ touchscreen-x-plate-ohms: true
additionalProperties: false
@@ -59,3 +60,11 @@ examples:
io-channels = <&adc 24>, <&adc 25>, <&adc 26>;
io-channel-names = "x", "y", "pressure";
};
+ - |
+ resistive_touch {
+ compatible = "resistive-adc-touch";
+ touchscreen-min-pressure = <50000>;
+ io-channels = <&adc 1>, <&adc 2>, <&adc 3>, <&adc 4>;
+ io-channel-names = "x", "y", "z1", "z2";
+ touchscreen-x-plate-ohms = <800>;
+ };
--
2.29.2
On Tue, 18 May 2021 14:57:47 +0200, Oleksij Rempel wrote:
> For pressure calculation based on plates resistance we need some additional
> properties:
> - z1 and z2 channels with additional measurements between plates
> - actual resistance of the touchscreen. Currently we use only
> X-resistance.
>
> Signed-off-by: Oleksij Rempel <[email protected]>
> ---
> .../bindings/input/touchscreen/resistive-adc-touch.yaml | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):
yamllint warnings/errors:
dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.example.dt.yaml: resistive_touch: io-channels: [[4294967295, 1], [4294967295, 2], [4294967295, 3], [4294967295, 4]] is too long
From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.example.dt.yaml: resistive_touch: io-channels: Additional items are not allowed ([4294967295, 4] was unexpected)
From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.example.dt.yaml: resistive_touch: io-channel-names:2: 'pressure' was expected
From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.example.dt.yaml: resistive_touch: io-channel-names: ['x', 'y', 'z1', 'z2'] is too long
From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.example.dt.yaml: resistive_touch: io-channel-names: Additional items are not allowed ('z2' was unexpected)
From schema: /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/input/touchscreen/resistive-adc-touch.yaml
See https://patchwork.ozlabs.org/patch/1480237
This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.
If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:
pip3 install dtschema --upgrade
Please check and re-submit.