[PATCH 0/5] Minor Imagis driver refactoring and support for IST4050

[PATCH 0/5] Minor Imagis driver refactoring and support for IST4050

[Markuss Broks via B4 Relay]

The Imagis IST4050 is a touchscreen IC of the IST40xx family. It shares
the register interface, the power-up sequence and the coordinate format
with IST3038C, but reports touches differently: instead of a per-index
contact snapshot paired with a "pressed" bitmask in the interrupt
message, the controller exposes one record per contact, 8 bytes apart,
carrying a hardware-assigned touch ID and a press/release event type in
its upper byte. The bits which hold the contact area on IST3038C hold
the event type on these chips, and no contact area is available in the
coordinate word.

Patch 1 documents the IST4050 compatible. Patch 2 stops reporting
coordinates of released contacts; besides avoiding pointless events on
slots which have just been deactivated, this is required for IST40xx,
where release records must not be parsed for the contact area. Patch 3
replaces the protocol_b flag with an enum which describes each touch
reporting format, patch 4 adds support for the IST40xx reporting format
and patch 5 wires the chip up.

The series has been tested on IST4050 (Samsung Galaxy A70 SM-A705FN).
No functional change is intended for the already-supported chips,
except that coordinates are no longer reported for contacts being released.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
Markuss Broks (5):
      dt-bindings: input: touchscreen: imagis: add compatible for IST4050
      Input: imagis - do not report coordinates of released contacts
      Input: imagis - replace the protocol_b flag with a protocol enum
      Input: imagis - add support for the IST40xx touch reporting format
      Input: imagis - add support for IST4050

 .../input/touchscreen/imagis,ist3038c.yaml         |  3 +-
 drivers/input/touchscreen/Kconfig                  |  2 +-
 drivers/input/touchscreen/imagis.c                 | 83 +++++++++++++++++++---
 3 files changed, 76 insertions(+), 12 deletions(-)
---
base-commit: 415606a7be939835db9b0d6b711887586646346d
change-id: 20260820-imagis-40xx-62fd11f8d7f8

Best regards,
--  
Markuss Broks <markuss.broks@gmail.com>

[PATCH 1/5] dt-bindings: input: touchscreen: imagis: add compatible for IST4050

[Markuss Broks via B4 Relay]

From: Markuss Broks <markuss.broks@gmail.com>

The IST4050 is a touchscreen IC of the Imagis IST40xx family. It shares
the register interface with IST3038C, but uses a different, event-based
touch reporting format and does not have touch keys.

The binding no longer covers only the IST30XXC family, so generalize its
title as well.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 .../devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml         | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml b/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
index dfaffbc398d3..a4f3e2f0cf45 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
@@ -4,7 +4,7 @@
 $id: http://devicetree.org/schemas/input/touchscreen/imagis,ist3038c.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Imagis IST30XXC family touchscreen controller
+title: Imagis touchscreen controller
 
 maintainers:
   - Markuss Broks <markuss.broks@gmail.com>
@@ -20,6 +20,7 @@ properties:
       - imagis,ist3038b
       - imagis,ist3038c
       - imagis,ist3038h
+      - imagis,ist4050
 
   reg:
     maxItems: 1

-- 
2.55.0

[PATCH 2/5] Input: imagis - do not report coordinates of released contacts

[Markuss Broks via B4 Relay]

From: Markuss Broks <markuss.broks@gmail.com>

The position and the contact area are currently reported even for
contacts which are being released. The slot has already been deactivated
at that point, so these events carry no information for userspace.
Report the position and the contact area only for active contacts.

This also prepares the driver for the IST40xx family: its per-contact
records carry an event type in the bits which hold the contact area on
the currently supported chips, so release records must not be parsed for
coordinates or the contact area.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 drivers/input/touchscreen/imagis.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/imagis.c b/drivers/input/touchscreen/imagis.c
index 7bbb00beec3b..7cc91f97c06e 100644
--- a/drivers/input/touchscreen/imagis.c
+++ b/drivers/input/touchscreen/imagis.c
@@ -127,6 +127,8 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 	finger_pressed = FIELD_GET(IST3038C_FINGER_STATUS_MASK, intr_message);
 
 	for (i = 0; i < finger_count; i++) {
+		bool pressed;
+
 		if (ts->tdata->protocol_b)
 			error = imagis_i2c_read_reg(ts,
 						    ts->tdata->touch_coord_cmd + (i * 4),
@@ -141,9 +143,13 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 			goto out;
 		}
 
+		pressed = finger_pressed & BIT(i);
+
 		input_mt_slot(ts->input_dev, i);
-		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER,
-					   finger_pressed & BIT(i));
+		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, pressed);
+		if (!pressed)
+			continue;
+
 		touchscreen_report_pos(ts->input_dev, &ts->prop,
 				       FIELD_GET(IST3038C_X_MASK, finger_status),
 				       FIELD_GET(IST3038C_Y_MASK, finger_status),

-- 
2.55.0

[PATCH 3/5] Input: imagis - replace the protocol_b flag with a protocol enum

[Markuss Broks via B4 Relay]

From: Markuss Broks <markuss.broks@gmail.com>

The driver tells the two supported touch reporting formats apart with
the protocol_b flag. The naming is unfortunate: "protocol B" is the
format of the IST30XXC series, while the B-suffixed chips use the
unnamed other format. Adding support for the IST40xx family is about to
introduce a third format, at which point a collection of booleans gets
easy to misuse.

Replace the flag with an enum which describes each reporting format:
IMAGIS_PROTOCOL_SHARED_REGISTER for the single coordinate register
shared by all contacts (IST3038, IST3038B and IST3038H), and
IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS for one coordinate register per
contact (IST3032C and IST3038C).

No functional change intended.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 drivers/input/touchscreen/imagis.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/imagis.c b/drivers/input/touchscreen/imagis.c
index 7cc91f97c06e..6552d97efe32 100644
--- a/drivers/input/touchscreen/imagis.c
+++ b/drivers/input/touchscreen/imagis.c
@@ -44,12 +44,19 @@
 #define IST3038C_FINGER_STATUS_MASK	GENMASK(9, 0)
 #define IST3032C_KEY_STATUS_MASK	GENMASK(20, 16)
 
+enum imagis_protocol {
+	/* one coordinate register shared by all contacts */
+	IMAGIS_PROTOCOL_SHARED_REGISTER,
+	/* one coordinate register per contact */
+	IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS,
+};
+
 struct imagis_properties {
 	unsigned int interrupt_msg_cmd;
 	unsigned int touch_coord_cmd;
 	unsigned int whoami_cmd;
 	unsigned int whoami_val;
-	bool protocol_b;
+	enum imagis_protocol protocol;
 	bool touch_keys_supported;
 };
 
@@ -129,7 +136,7 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 	for (i = 0; i < finger_count; i++) {
 		bool pressed;
 
-		if (ts->tdata->protocol_b)
+		if (ts->tdata->protocol == IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS)
 			error = imagis_i2c_read_reg(ts,
 						    ts->tdata->touch_coord_cmd + (i * 4),
 						    &finger_status);
@@ -410,8 +417,8 @@ static const struct imagis_properties imagis_3032c_data = {
 	.touch_coord_cmd = IST3038C_REG_TOUCH_COORD,
 	.whoami_cmd = IST3038C_REG_CHIPID,
 	.whoami_val = IST3032C_WHOAMI,
+	.protocol = IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS,
 	.touch_keys_supported = true,
-	.protocol_b = true,
 };
 
 static const struct imagis_properties imagis_3038_data = {
@@ -419,6 +426,7 @@ static const struct imagis_properties imagis_3038_data = {
 	.touch_coord_cmd = IST30XX_REG_STATUS,
 	.whoami_cmd = IST30XX_REG_CHIPID,
 	.whoami_val = IST3038_WHOAMI,
+	.protocol = IMAGIS_PROTOCOL_SHARED_REGISTER,
 	.touch_keys_supported = true,
 };
 
@@ -427,6 +435,7 @@ static const struct imagis_properties imagis_3038b_data = {
 	.touch_coord_cmd = IST30XX_REG_STATUS,
 	.whoami_cmd = IST3038B_REG_CHIPID,
 	.whoami_val = IST3038B_WHOAMI,
+	.protocol = IMAGIS_PROTOCOL_SHARED_REGISTER,
 };
 
 static const struct imagis_properties imagis_3038c_data = {
@@ -434,7 +443,7 @@ static const struct imagis_properties imagis_3038c_data = {
 	.touch_coord_cmd = IST3038C_REG_TOUCH_COORD,
 	.whoami_cmd = IST3038C_REG_CHIPID,
 	.whoami_val = IST3038C_WHOAMI,
-	.protocol_b = true,
+	.protocol = IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS,
 };
 
 static const struct imagis_properties imagis_3038h_data = {
@@ -442,6 +451,7 @@ static const struct imagis_properties imagis_3038h_data = {
 	.touch_coord_cmd = IST3038C_REG_TOUCH_COORD,
 	.whoami_cmd = IST3038C_REG_CHIPID,
 	.whoami_val = IST3038H_WHOAMI,
+	.protocol = IMAGIS_PROTOCOL_SHARED_REGISTER,
 };
 
 static const struct of_device_id imagis_of_match[] = {

-- 
2.55.0

[PATCH 4/5] Input: imagis - add support for the IST40xx touch reporting format

[Markuss Broks via B4 Relay]

From: Markuss Broks <markuss.broks@gmail.com>

Chips of the Imagis IST40xx family share the register interface and the
coordinate format with IST3038C, but report touches differently: the
per-contact records are 8 bytes apart, and instead of pairing the record
index with a "pressed" bitmask from the interrupt message, each record
carries a hardware-assigned touch ID (1-based, bits 31:28) and an event
type (press or release, bits 27:24). The event type occupies the bits
which hold the contact area on IST3038C, and no contact area is
available in the coordinate word.

Add an IMAGIS_PROTOCOL_TOUCH_EVENTS variant for this format: derive the
contact slot from the touch ID instead of the record index, translate
press/release events into the contact state, ignore records with an
out-of-range touch ID or an unknown event type, and do not declare the
ABS_MT_TOUCH_MAJOR axis.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 drivers/input/touchscreen/imagis.c | 49 +++++++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 6 deletions(-)

diff --git a/drivers/input/touchscreen/imagis.c b/drivers/input/touchscreen/imagis.c
index 6552d97efe32..5254cccdd653 100644
--- a/drivers/input/touchscreen/imagis.c
+++ b/drivers/input/touchscreen/imagis.c
@@ -44,11 +44,18 @@
 #define IST3038C_FINGER_STATUS_MASK	GENMASK(9, 0)
 #define IST3032C_KEY_STATUS_MASK	GENMASK(20, 16)
 
+#define IST40XX_TOUCH_ID_MASK		GENMASK(31, 28)
+#define IST40XX_TOUCH_EVENT_MASK	GENMASK(27, 24)
+#define IST40XX_TOUCH_EVENT_PRESS	1
+#define IST40XX_TOUCH_EVENT_RELEASE	2
+
 enum imagis_protocol {
 	/* one coordinate register shared by all contacts */
 	IMAGIS_PROTOCOL_SHARED_REGISTER,
 	/* one coordinate register per contact */
 	IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS,
+	/* one record per contact, carrying a touch ID and an event type */
+	IMAGIS_PROTOCOL_TOUCH_EVENTS,
 };
 
 struct imagis_properties {
@@ -134,9 +141,14 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 	finger_pressed = FIELD_GET(IST3038C_FINGER_STATUS_MASK, intr_message);
 
 	for (i = 0; i < finger_count; i++) {
+		unsigned int slot = i;
 		bool pressed;
 
-		if (ts->tdata->protocol == IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS)
+		if (ts->tdata->protocol == IMAGIS_PROTOCOL_TOUCH_EVENTS)
+			error = imagis_i2c_read_reg(ts,
+						    ts->tdata->touch_coord_cmd + (i * 8),
+						    &finger_status);
+		else if (ts->tdata->protocol == IMAGIS_PROTOCOL_PER_CONTACT_REGISTERS)
 			error = imagis_i2c_read_reg(ts,
 						    ts->tdata->touch_coord_cmd + (i * 4),
 						    &finger_status);
@@ -150,9 +162,31 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 			goto out;
 		}
 
-		pressed = finger_pressed & BIT(i);
+		if (ts->tdata->protocol == IMAGIS_PROTOCOL_TOUCH_EVENTS) {
+			unsigned int id = FIELD_GET(IST40XX_TOUCH_ID_MASK,
+						    finger_status);
+
+			if (!id || id > IST3038C_MAX_FINGER_NUM)
+				continue;
+
+			slot = id - 1;
+
+			switch (FIELD_GET(IST40XX_TOUCH_EVENT_MASK,
+					  finger_status)) {
+			case IST40XX_TOUCH_EVENT_PRESS:
+				pressed = true;
+				break;
+			case IST40XX_TOUCH_EVENT_RELEASE:
+				pressed = false;
+				break;
+			default:
+				continue;
+			}
+		} else {
+			pressed = finger_pressed & BIT(i);
+		}
 
-		input_mt_slot(ts->input_dev, i);
+		input_mt_slot(ts->input_dev, slot);
 		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, pressed);
 		if (!pressed)
 			continue;
@@ -161,8 +195,10 @@ static irqreturn_t imagis_interrupt(int irq, void *dev_id)
 				       FIELD_GET(IST3038C_X_MASK, finger_status),
 				       FIELD_GET(IST3038C_Y_MASK, finger_status),
 				       true);
-		input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
-				 FIELD_GET(IST3038C_AREA_MASK, finger_status));
+		if (ts->tdata->protocol != IMAGIS_PROTOCOL_TOUCH_EVENTS)
+			input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
+					 FIELD_GET(IST3038C_AREA_MASK,
+						   finger_status));
 	}
 
 	key_pressed = FIELD_GET(IST3032C_KEY_STATUS_MASK, intr_message);
@@ -255,7 +291,8 @@ static int imagis_init_input_dev(struct imagis_ts *ts)
 
 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
-	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 16, 0, 0);
+	if (ts->tdata->protocol != IMAGIS_PROTOCOL_TOUCH_EVENTS)
+		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 16, 0, 0);
 	if (ts->tdata->touch_keys_supported) {
 		ts->num_keycodes = of_property_read_variable_u32_array(
 				ts->client->dev.of_node, "linux,keycodes",

-- 
2.55.0

[PATCH 5/5] Input: imagis - add support for IST4050

[Markuss Broks via B4 Relay]

From: Markuss Broks <markuss.broks@gmail.com>

The Imagis IST4050 shares the register interface and the power-up
sequence with IST3038C, and reports touches using the IST40xx touch
reporting format. Its chip ID register reads back 0x4050.

Also mention the IST40xx family in the Kconfig help text, and refer to
the older chips as IST30xx, since the driver supports more than the C
variants.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
 drivers/input/touchscreen/Kconfig  |  2 +-
 drivers/input/touchscreen/imagis.c | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 9b9ae8ac3f7f..96fdc4384a75 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -705,7 +705,7 @@ config TOUCHSCREEN_IMAGIS
 	tristate "Imagis touchscreen support"
 	depends on I2C
 	help
-	  Say Y here if you have an Imagis IST30xxC touchscreen.
+	  Say Y here if you have an Imagis IST30xx or IST40xx touchscreen.
 	  If unsure, say N.
 
 	  To compile this driver as a module, choose M here: the
diff --git a/drivers/input/touchscreen/imagis.c b/drivers/input/touchscreen/imagis.c
index 5254cccdd653..9bf5afd43848 100644
--- a/drivers/input/touchscreen/imagis.c
+++ b/drivers/input/touchscreen/imagis.c
@@ -23,6 +23,7 @@
 #define IST3032C_WHOAMI			0x32c
 #define IST3038C_WHOAMI			0x38c
 #define IST3038H_WHOAMI			0x38d
+#define IST4050_WHOAMI			0x4050
 
 #define IST3038B_REG_CHIPID		0x30
 #define IST3038B_WHOAMI			0x30380b
@@ -491,12 +492,21 @@ static const struct imagis_properties imagis_3038h_data = {
 	.protocol = IMAGIS_PROTOCOL_SHARED_REGISTER,
 };
 
+static const struct imagis_properties imagis_4050_data = {
+	.interrupt_msg_cmd = IST3038C_REG_INTR_MESSAGE,
+	.touch_coord_cmd = IST3038C_REG_TOUCH_COORD,
+	.whoami_cmd = IST3038C_REG_CHIPID,
+	.whoami_val = IST4050_WHOAMI,
+	.protocol = IMAGIS_PROTOCOL_TOUCH_EVENTS,
+};
+
 static const struct of_device_id imagis_of_match[] = {
 	{ .compatible = "imagis,ist3032c", .data = &imagis_3032c_data },
 	{ .compatible = "imagis,ist3038", .data = &imagis_3038_data },
 	{ .compatible = "imagis,ist3038b", .data = &imagis_3038b_data },
 	{ .compatible = "imagis,ist3038c", .data = &imagis_3038c_data },
 	{ .compatible = "imagis,ist3038h", .data = &imagis_3038h_data },
+	{ .compatible = "imagis,ist4050", .data = &imagis_4050_data },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, imagis_of_match);

-- 
2.55.0

Re: [PATCH 1/5] dt-bindings: input: touchscreen: imagis: add compatible for IST4050

[Conor Dooley]

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On Sat, Aug 22, 2026 at 12:30:13AM +0300, Markuss Broks via B4 Relay wrote:
> From: Markuss Broks <markuss.broks@gmail.com>
> 
> The IST4050 is a touchscreen IC of the Imagis IST40xx family. It shares
> the register interface with IST3038C, but uses a different, event-based
> touch reporting format and does not have touch keys.
> 
> The binding no longer covers only the IST30XXC family, so generalize its
> title as well.
> 
> Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
> ---
>  .../devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml         | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml b/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
> index dfaffbc398d3..a4f3e2f0cf45 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
> +++ b/Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml
> @@ -4,7 +4,7 @@
>  $id: http://devicetree.org/schemas/input/touchscreen/imagis,ist3038c.yaml#
>  $schema: http://devicetree.org/meta-schemas/core.yaml#
>  
> -title: Imagis IST30XXC family touchscreen controller
> +title: Imagis touchscreen controller

"controllers" probably.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

>  
>  maintainers:
>    - Markuss Broks <markuss.broks@gmail.com>
> @@ -20,6 +20,7 @@ properties:
>        - imagis,ist3038b
>        - imagis,ist3038c
>        - imagis,ist3038h
> +      - imagis,ist4050
>  
>    reg:
>      maxItems: 1
> 
> -- 
> 2.55.0
> 
> 

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