[PATCH 0/4] Input: hynitron-cst816x: axis properties and gesture keys

[PATCH 0/4] Input: hynitron-cst816x: axis properties and gesture keys

[Daniel Golle]

This series improves the hynitron-cst816x touchscreen driver. It makes
the driver respect the common touchscreen axis properties, which are
now documented in the binding as well, and it keeps gesture keys from
getting stuck.

The gesture key is reported with the controller's touch flag as its
value, so the key stays pressed once the controller stops reporting
the gesture code. The controller has no lift event to offer, so the
keys are now released on the first report carrying no gesture code, or
40 ms after the last one that carried a code, whichever comes first.

Daniel Golle (4):
  dt-bindings: input: touchscreen: hynitron,cst816x: configure axes
  Input: hynitron-cst816x: respect touchscreen DT properties
  Input: hynitron-cst816x: release gesture keys
  Input: hynitron-cst816x: time out gesture key release

 .../input/touchscreen/hynitron,cst816x.yaml   |  8 +++
 drivers/input/touchscreen/hynitron-cst816x.c  | 71 +++++++++++++++++--
 2 files changed, 74 insertions(+), 5 deletions(-)


base-commit: 6474fa070f2b8013b4b87350b775b8c3be6e8aac
-- 
2.55.0

[PATCH 1/4] dt-bindings: input: touchscreen: hynitron,cst816x: configure axes

[Daniel Golle]

Reference touchscreen.yaml and allow properties
'touchscreen-inverted-x', 'touchscreen-inverted-y' and
'touchscreen-swapped-x-y'.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 .../bindings/input/touchscreen/hynitron,cst816x.yaml      | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml b/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
index 72d4da636881e..ba56bf61038c5 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
@@ -36,6 +36,10 @@ properties:
       - description: Slide right gesture
       - description: Long press gesture
 
+  touchscreen-inverted-x: true
+  touchscreen-inverted-y: true
+  touchscreen-swapped-x-y: true
+
 required:
   - compatible
   - reg
@@ -43,6 +47,9 @@ required:
 
 additionalProperties: false
 
+allOf:
+  - $ref: touchscreen.yaml#
+
 examples:
   - |
     #include <dt-bindings/gpio/gpio.h>
@@ -59,6 +66,7 @@ examples:
             reset-gpios = <&gpio 17 GPIO_ACTIVE_LOW>;
             linux,keycodes = <KEY_UP>, <KEY_DOWN>, <KEY_LEFT>, <KEY_RIGHT>,
                              <BTN_TOOL_TRIPLETAP>;
+            touchscreen-swapped-x-y;
         };
     };
 
-- 
2.55.0

Re: [PATCH 1/4] dt-bindings: input: touchscreen: hynitron,cst816x: configure axes

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 1715 bytes --]

On Thu, Oct 01, 2026 at 11:52:31AM +0100, Daniel Golle wrote:
> Reference touchscreen.yaml and allow properties
> 'touchscreen-inverted-x', 'touchscreen-inverted-y' and
> 'touchscreen-swapped-x-y'.

This is a useless commit message, it just says what the diff does.
Please provide a justification for why this is the right thing to do.
pw-bot: changes-requested

> 
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
>  .../bindings/input/touchscreen/hynitron,cst816x.yaml      | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml b/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
> index 72d4da636881e..ba56bf61038c5 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
> +++ b/Documentation/devicetree/bindings/input/touchscreen/hynitron,cst816x.yaml
> @@ -36,6 +36,10 @@ properties:
>        - description: Slide right gesture
>        - description: Long press gesture
>  
> +  touchscreen-inverted-x: true
> +  touchscreen-inverted-y: true
> +  touchscreen-swapped-x-y: true
> +
>  required:
>    - compatible
>    - reg
> @@ -43,6 +47,9 @@ required:
>  
>  additionalProperties: false
>  
> +allOf:
> +  - $ref: touchscreen.yaml#
> +
>  examples:
>    - |
>      #include <dt-bindings/gpio/gpio.h>
> @@ -59,6 +66,7 @@ examples:
>              reset-gpios = <&gpio 17 GPIO_ACTIVE_LOW>;
>              linux,keycodes = <KEY_UP>, <KEY_DOWN>, <KEY_LEFT>, <KEY_RIGHT>,
>                               <BTN_TOOL_TRIPLETAP>;
> +            touchscreen-swapped-x-y;
>          };
>      };
>  
> -- 
> 2.55.0

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[PATCH 2/4] Input: hynitron-cst816x: respect touchscreen DT properties

[Daniel Golle]

Parse common touchscreen properties and use touchscreen_report_pos()
instead of reporting raw absolute position.

This makes the driver respect the touchscreen-inverted-x,
touchscreen-inverted-y and touchscreen-swapped-x-y properties

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/input/touchscreen/hynitron-cst816x.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c
index 47d9cd7412d1b..865c5a767ba01 100644
--- a/drivers/input/touchscreen/hynitron-cst816x.c
+++ b/drivers/input/touchscreen/hynitron-cst816x.c
@@ -11,6 +11,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
+#include <linux/input/touchscreen.h>
 #include <linux/unaligned.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -31,6 +32,7 @@ struct cst816x_priv {
 	struct input_dev *input;
 	unsigned int keycode[CST816X_NUM_KEYS];
 	unsigned int keycodemax;
+	struct touchscreen_properties prop;
 };
 
 static int cst816x_parse_keycodes(struct device *dev, struct cst816x_priv *priv)
@@ -142,6 +144,7 @@ static int cst816x_register_input(struct cst816x_priv *priv)
 	input_set_abs_params(priv->input, ABS_X, 0, 240, 0, 0);
 	input_set_abs_params(priv->input, ABS_Y, 0, 240, 0, 0);
 	input_set_capability(priv->input, EV_KEY, BTN_TOUCH);
+	touchscreen_parse_properties(priv->input, false, &priv->prop);
 
 	priv->input->keycode = priv->keycode;
 	priv->input->keycodesize = sizeof(priv->keycode[0]);
@@ -173,8 +176,8 @@ static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 	if (!cst816x_process_touch(priv, &tch))
 		return IRQ_HANDLED;
 
-	input_report_abs(priv->input, ABS_X, tch.abs_x);
-	input_report_abs(priv->input, ABS_Y, tch.abs_y);
+	touchscreen_report_pos(priv->input, &priv->prop,
+			       tch.abs_x, tch.abs_y, false);
 
 	if (tch.gest)
 		input_report_key(priv->input,
-- 
2.55.0

[PATCH 3/4] Input: hynitron-cst816x: release gesture keys

[Daniel Golle]

The gesture key is reported with the value of the touch flag, so it
stays pressed once the controller stops reporting the gesture code
while the finger is still down. Report the press on its own and
release the keys the input core still holds down on the first report
that carries no gesture code.

Fixes: c87a819bec86 ("Input: add driver for Hynitron CST816x series")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/input/touchscreen/hynitron-cst816x.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c
index 865c5a767ba01..e2093518e8af1 100644
--- a/drivers/input/touchscreen/hynitron-cst816x.c
+++ b/drivers/input/touchscreen/hynitron-cst816x.c
@@ -168,6 +168,18 @@ static void cst816x_reset(struct cst816x_priv *priv)
 	msleep(100);
 }
 
+static void cst816x_release_keys(struct cst816x_priv *priv)
+{
+	unsigned int i;
+
+	for (i = 0; i < priv->keycodemax; i++) {
+		if (!test_bit(priv->keycode[i], priv->input->key))
+			continue;
+
+		input_report_key(priv->input, priv->keycode[i], 0);
+	}
+}
+
 static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 {
 	struct cst816x_priv *priv = cookie;
@@ -181,8 +193,9 @@ static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 
 	if (tch.gest)
 		input_report_key(priv->input,
-				 priv->keycode[cst816x_gest_idx(tch.gest)],
-				 tch.active);
+				 priv->keycode[cst816x_gest_idx(tch.gest)], 1);
+	else
+		cst816x_release_keys(priv);
 
 	input_report_key(priv->input, BTN_TOUCH, tch.active);
 
-- 
2.55.0

[PATCH 4/4] Input: hynitron-cst816x: time out gesture key release

[Daniel Golle]

The controller reports a gesture code once and can then stay quiet
until the next touch, which leaves the gesture key pressed for as long
as the panel is left alone. Release the gesture keys 40 ms after the
last report that carried a gesture code, so that the release comes
from whichever happens first, the timeout or a report without a
gesture code. The 40 ms matches TSC200X_PENUP_TIME_MS, chosen there
for the same want of a lift event from the controller, and has to stay
above the interval between consecutive reports of a held gesture.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/input/touchscreen/hynitron-cst816x.c | 51 ++++++++++++++++++--
 1 file changed, 48 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c
index e2093518e8af1..30f8ea314ed2c 100644
--- a/drivers/input/touchscreen/hynitron-cst816x.c
+++ b/drivers/input/touchscreen/hynitron-cst816x.c
@@ -15,9 +15,12 @@
 #include <linux/unaligned.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
 
 #define CST816X_RD_REG		0x01
 #define CST816X_NUM_KEYS	5
+#define CST816X_GEST_HOLD_MS	40
 
 struct cst816x_touch {
 	u8 gest;
@@ -32,6 +35,9 @@ struct cst816x_priv {
 	struct input_dev *input;
 	unsigned int keycode[CST816X_NUM_KEYS];
 	unsigned int keycodemax;
+	struct timer_list release_timer;
+	/* lock keeps the timeout out of the middle of a report */
+	spinlock_t lock;
 	struct touchscreen_properties prop;
 };
 
@@ -168,8 +174,9 @@ static void cst816x_reset(struct cst816x_priv *priv)
 	msleep(100);
 }
 
-static void cst816x_release_keys(struct cst816x_priv *priv)
+static bool cst816x_release_keys(struct cst816x_priv *priv)
 {
+	bool released = false;
 	unsigned int i;
 
 	for (i = 0; i < priv->keycodemax; i++) {
@@ -177,33 +184,65 @@ static void cst816x_release_keys(struct cst816x_priv *priv)
 			continue;
 
 		input_report_key(priv->input, priv->keycode[i], 0);
+		released = true;
 	}
+
+	return released;
+}
+
+static void cst816x_release_timeout(struct timer_list *t)
+{
+	struct cst816x_priv *priv = timer_container_of(priv, t, release_timer);
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	if (cst816x_release_keys(priv))
+		input_sync(priv->input);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
 }
 
 static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 {
 	struct cst816x_priv *priv = cookie;
 	struct cst816x_touch tch;
+	unsigned long flags;
 
 	if (!cst816x_process_touch(priv, &tch))
 		return IRQ_HANDLED;
 
+	spin_lock_irqsave(&priv->lock, flags);
+
 	touchscreen_report_pos(priv->input, &priv->prop,
 			       tch.abs_x, tch.abs_y, false);
 
-	if (tch.gest)
+	if (tch.gest) {
 		input_report_key(priv->input,
 				 priv->keycode[cst816x_gest_idx(tch.gest)], 1);
-	else
+		mod_timer(&priv->release_timer,
+			  jiffies + msecs_to_jiffies(CST816X_GEST_HOLD_MS));
+	} else {
+		timer_delete(&priv->release_timer);
 		cst816x_release_keys(priv);
+	}
 
 	input_report_key(priv->input, BTN_TOUCH, tch.active);
 
 	input_sync(priv->input);
 
+	spin_unlock_irqrestore(&priv->lock, flags);
+
 	return IRQ_HANDLED;
 }
 
+static void cst816x_timer_stop(void *data)
+{
+	struct cst816x_priv *priv = data;
+
+	timer_delete_sync(&priv->release_timer);
+}
+
 static int cst816x_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -215,6 +254,8 @@ static int cst816x_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	priv->client = client;
+	spin_lock_init(&priv->lock);
+	timer_setup(&priv->release_timer, cst816x_release_timeout, 0);
 
 	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(priv->reset))
@@ -232,6 +273,10 @@ static int cst816x_probe(struct i2c_client *client)
 	if (error)
 		return dev_err_probe(dev, error, "input register failed\n");
 
+	error = devm_add_action_or_reset(dev, cst816x_timer_stop, priv);
+	if (error)
+		return error;
+
 	error = devm_request_threaded_irq(dev, client->irq,
 					  NULL, cst816x_irq_cb, IRQF_ONESHOT,
 					  dev_driver_string(dev), priv);
-- 
2.55.0