Use touch-overlay to support overlay objects such as buttons and a
resized frame defined in the device tree.

A key event will be generated if the coordinates of a touch event are
within the area defined by the button properties.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Signed-off-by: Javier Carrasco <javier.carrasco@wolfvision.net>
---
 drivers/input/touchscreen/st1232.c | 48 +++++++++++++++++++++++++++-----------
 1 file changed, 34 insertions(+), 14 deletions(-)

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 6475084aee1b..4fa31447dbc1 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -22,6 +22,7 @@
 #include <linux/pm_qos.h>
 #include <linux/slab.h>
 #include <linux/types.h>
+#include <linux/input/touch-overlay.h>
 
 #define ST1232_TS_NAME	"st1232-ts"
 #define ST1633_TS_NAME	"st1633-ts"
@@ -57,6 +58,7 @@ struct st1232_ts_data {
 	struct dev_pm_qos_request low_latency_req;
 	struct gpio_desc *reset_gpio;
 	const struct st_chip_info *chip_info;
+	struct list_head touch_overlay_list;
 	int read_buf_len;
 	u8 *read_buf;
 };
@@ -138,14 +140,20 @@ static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
 
 	for (i = 0; i < ts->chip_info->max_fingers; i++) {
 		u8 *buf = &ts->read_buf[i * 4];
+		bool contact = buf[0] & BIT(7);
+		unsigned int x, y;
 
-		if (buf[0] & BIT(7)) {
-			unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
-			unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];
-
-			touchscreen_set_mt_pos(&pos[n_contacts],
-					       &ts->prop, x, y);
+		if (contact) {
+			x = ((buf[0] & 0x70) << 4) | buf[1];
+			y = ((buf[0] & 0x07) << 8) | buf[2];
+		}
+		if (touch_overlay_process_event(&ts->touch_overlay_list, input,
+						contact ? &x : NULL,
+						contact ? &y : NULL, i))
+			continue;
 
+		if (contact) {
+			touchscreen_set_mt_pos(&pos[n_contacts], &ts->prop, x, y);
 			/* st1232 includes a z-axis / touch strength */
 			if (ts->chip_info->have_z)
 				z[n_contacts] = ts->read_buf[i + 6];
@@ -292,18 +300,30 @@ static int st1232_ts_probe(struct i2c_client *client)
 	if (error)
 		return error;
 
-	/* Read resolution from the chip */
-	error = st1232_ts_read_resolution(ts, &max_x, &max_y);
-	if (error) {
-		dev_err(&client->dev,
-			"Failed to read resolution: %d\n", error);
-		return error;
-	}
-
 	if (ts->chip_info->have_z)
 		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
 				     ts->chip_info->max_area, 0, 0);
 
+	/* map overlay objects if defined in the device tree */
+	INIT_LIST_HEAD(&ts->touch_overlay_list);
+	error = touch_overlay_map(&ts->touch_overlay_list, input_dev);
+	if (error)
+		return error;
+
+	if (touch_overlay_mapped_touchscreen(&ts->touch_overlay_list)) {
+		/* Read resolution from the overlay touchscreen if defined */
+		touch_overlay_get_touchscreen_abs(&ts->touch_overlay_list,
+						  &max_x, &max_y);
+	} else {
+		/* Read resolution from the chip */
+		error = st1232_ts_read_resolution(ts, &max_x, &max_y);
+		if (error) {
+			dev_err(&client->dev,
+				"Failed to read resolution: %d\n", error);
+			return error;
+		}
+	}
+
 	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
 			     0, max_x, 0, 0);
 	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,

-- 
2.40.1

Hi Javier,

On Wed, Jun 26, 2024 at 11:56:16AM +0200, Javier Carrasco wrote:
> Use touch-overlay to support overlay objects such as buttons and a
> resized frame defined in the device tree.
> 
> A key event will be generated if the coordinates of a touch event are
> within the area defined by the button properties.
> 
> Reviewed-by: Jeff LaBundy <jeff@labundy.com>
> Signed-off-by: Javier Carrasco <javier.carrasco@wolfvision.net>
> ---
>  drivers/input/touchscreen/st1232.c | 48 +++++++++++++++++++++++++++-----------
>  1 file changed, 34 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
> index 6475084aee1b..4fa31447dbc1 100644
> --- a/drivers/input/touchscreen/st1232.c
> +++ b/drivers/input/touchscreen/st1232.c
> @@ -22,6 +22,7 @@
>  #include <linux/pm_qos.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
> +#include <linux/input/touch-overlay.h>
>  
>  #define ST1232_TS_NAME	"st1232-ts"
>  #define ST1633_TS_NAME	"st1633-ts"
> @@ -57,6 +58,7 @@ struct st1232_ts_data {
>  	struct dev_pm_qos_request low_latency_req;
>  	struct gpio_desc *reset_gpio;
>  	const struct st_chip_info *chip_info;
> +	struct list_head touch_overlay_list;
>  	int read_buf_len;
>  	u8 *read_buf;
>  };
> @@ -138,14 +140,20 @@ static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
>  
>  	for (i = 0; i < ts->chip_info->max_fingers; i++) {
>  		u8 *buf = &ts->read_buf[i * 4];
> +		bool contact = buf[0] & BIT(7);
> +		unsigned int x, y;
>  
> -		if (buf[0] & BIT(7)) {
> -			unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
> -			unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];
> -
> -			touchscreen_set_mt_pos(&pos[n_contacts],
> -					       &ts->prop, x, y);
> +		if (contact) {
> +			x = ((buf[0] & 0x70) << 4) | buf[1];
> +			y = ((buf[0] & 0x07) << 8) | buf[2];
> +		}
> +		if (touch_overlay_process_event(&ts->touch_overlay_list, input,
> +						contact ? &x : NULL,
> +						contact ? &y : NULL, i))
> +			continue;

So here is the exact issue I was talking about: you are using index of
the contact as a slot, which assumes that the device maintains position
of contacts in the overall event stream. However the driver uses input
core to track and assign slots (see calls to touchscreen_set_mt_pos()
and input_mt_assign_slots() below), which suggest that the touch
controller may reorder positions as needed.

Thanks.

-- 
Dmitry