[PATCH v6 0/3] Input: support for STM FTS5

[PATCH v6 0/3] Input: support for STM FTS5

[David Heidelberg via B4 Relay]

Used on various phones. Minimal viable driver.

Includes device-tree enabling touchscreen on Pixel 3.
Also, tested on Xiaomi Mi 8 (device-tree is not yet inside the mainline).

What is missing:
 - switching between AP and SLPI mode (to be able to wake up phone by touch)
 - firmware loading
 - anything above basic touch

Signed-off-by: David Heidelberg <david@ixit.cz>
---
Changes in v6:
- Enable only the multi-touch scan on FTS5 sense-on (0xff was wrong,
  only 0x01 is needed. This broke Xiaomi Mi 8 toucschreen).
- Fixed Y-coordinate comments. (Dmitry)
- Corrected event[0] parsing. (Dmitry)
- Dropped checking < 0 on unsigned area. (Dmitry)
- Dropped unnecessary i2c writes after reset. Verified against
  downstream driver. (Dmitry, Sashiko)
- Added pieces for supporting non-OF integration. (Sashiko)
- Shared input open/close into one impl. (Dmitry).
- Link to v5: https://patch.msgid.link/20260810-stmfts5-v5-0-0c737d929976@ixit.cz

Changes in v5:
- 3.3V is analog, 1.8V is digital supply. Fix that.
- Name the error variables "err" (Dmitry)
- Use scoped_guard() for ->running, and only set it once the scan
  mode has actually been enabled. (Dmitry)
- Use i2c_master_send() instead of open-coding a single-message
  i2c_transfer(). (Dmitry)
- Drivers may report coordinates outside the declared min/max, so
  remove the clamping. (Dmitry)
- BTN_TOUCH and INPUT_PROP_DIRECT are already set up by
  input_mt_init_slots(..., INPUT_MT_DIRECT). (Dmitry)
- Let the input core track contacts: drop the touch_id/stylus_id
  bitmaps and the hand-rolled BTN_TOUCH reporting, and sync the frame
  once per interrupt with input_mt_sync_frame() instead of calling
  input_sync() per contact event. The controller pushes contacts one
  by one into the event FIFO and only resends the ones that changed,
  so INPUT_MT_DROP_UNUSED is wrong here and is dropped as well. (Dmitry)
- Restore the FTS4 interrupts accidentally dropped by introduction of
  FTS5.
- mode-switch-gpios isn't required with stmfts5. Some designs, such as
  Xiaomi Mi 8, has no such GPIO connected and is limited to AP mode.
- Nit: updated example to use interrupts-extended.
- Nit: (maximum x/y coordinate reported + 1), corrected example.
- Link to v4: https://lore.kernel.org/r/20260409-stmfts5-v4-0-64fe62027db5@ixit.cz

Changes in v4:
- Wrap everything below enabling the supplies into stmfts_configure()
  to avoid bunch of gotos to power off on error (Dmitry T.)
- Finished chip specific ops and removed is_fts5. (Dmitry T.)
- Link to v3: https://lore.kernel.org/r/20260403-stmfts5-v3-0-5da768cfd201@ixit.cz

Changes in v3:
- s/touchscreen_pins/touchscreen_irq_n. (Konrad)
- Use interrupts-extended. (Konrad)
- Fixed rebase conflict against 8665ceb926ec ("Input: stmfts - use guard notation when acquiring mutex")
- Rename switch-gpios to mode-switch-gpios.
- Do not define properties in if:then: branches. (Krzysztof)
- Link to v2: https://lore.kernel.org/r/20260315-stmfts5-v2-0-70bc83ee9591@ixit.cz

Changes in v2:
- Fix typo in the binding s/switch-gpio/switch-gpios/.
- Deduplacate allOf. (Rob yamllint)
- Add missing S-off-by. (Dmitry B.)
- Dropped irq-gpios as it's not needed. (Konrad)
- Correct x and y touchscreen area size. (Konrad)
- Correct reset introduction commit description. (Krzysztof)
- Partially implemented chip specific ops. (Dmitry T.)
- Separeted license naming cleanup into separate commit (Dmitry T.)
- Link to v1: https://lore.kernel.org/r/20260301-stmfts5-v1-0-22c458b9ac68@ixit.cz

---
David Heidelberg (2):
      dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5
      Input: stmfts - support FTS5

Petr Hodina (1):
      arm64: dts: qcom: sdm845-google: Add STM FTS touchscreen support

 .../bindings/input/touchscreen/st,stmfts.yaml      |  29 +-
 .../arm64/boot/dts/qcom/sdm845-google-blueline.dts |  19 +-
 arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi |   2 +-
 drivers/input/touchscreen/stmfts.c                 | 407 ++++++++++++++++++---
 4 files changed, 406 insertions(+), 51 deletions(-)
---
base-commit: 7079a12d7506b07fb53b54a664bfad5fa9b16d70
change-id: 20260214-stmfts5-b47311fbd732

Best regards,
--  
David Heidelberg <david@ixit.cz>

[PATCH v6 1/3] dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5

[David Heidelberg via B4 Relay]

From: David Heidelberg <david@ixit.cz>

Introduce more recent STM FTS5 touchscreen support.

Signed-off-by: David Heidelberg <david@ixit.cz>
---
 .../bindings/input/touchscreen/st,stmfts.yaml      | 29 ++++++++++++++++------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
index 64c4f24ea3dd0..3de4bc5cd3f78 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
@@ -9,22 +9,21 @@ title: ST-Microelectronics FingerTip touchscreen controller
 maintainers:
   - Krzysztof Kozlowski <krzk@kernel.org>
 
 description:
   The ST-Microelectronics FingerTip device provides a basic touchscreen
   functionality. Along with it the user can enable the touchkey which can work
   as a basic HOME and BACK key for phones.
 
-allOf:
-  - $ref: touchscreen.yaml#
-
 properties:
   compatible:
-    const: st,stmfts
+    enum:
+      - st,stmfts
+      - st,stmfts5
 
   reg:
     maxItems: 1
 
   avdd-supply:
     description: Analogic power supply
 
   interrupts:
@@ -35,42 +34,56 @@ properties:
 
   touch-key-connected:
     type: boolean
     description: The touchkey feature is connected
 
   vdd-supply:
     description: Power supply
 
+  mode-switch-gpios:
+    description: Optional switch between touchscreen SLPI and AP mode.
+    maxItems: 1
+
   reset-gpios:
     description: Reset GPIO (active-low)
     maxItems: 1
 
 required:
   - compatible
   - reg
   - avdd-supply
   - interrupts
   - vdd-supply
 
+allOf:
+  - $ref: touchscreen.yaml#
+  - if:
+      not:
+        properties:
+          compatible:
+            const: st,stmfts5
+    then:
+      properties:
+        mode-switch-gpios: false
+
 unevaluatedProperties: false
 
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>
 
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
 
         touchscreen@49 {
             compatible = "st,stmfts";
             reg = <0x49>;
-            interrupt-parent = <&gpa1>;
-            interrupts = <1 IRQ_TYPE_LEVEL_LOW>;
-            touchscreen-size-x = <1599>;
-            touchscreen-size-y = <2559>;
+            interrupts-extended = <&gpa1 1 IRQ_TYPE_LEVEL_LOW>;
+            touchscreen-size-x = <1600>;
+            touchscreen-size-y = <2560>;
             touch-key-connected;
             avdd-supply = <&ldo30_reg>;
             vdd-supply = <&ldo31_reg>;
             ledvdd-supply = <&ldo33_reg>;
         };
     };

-- 
2.55.0

[PATCH v6 2/3] Input: stmfts - support FTS5

[David Heidelberg via B4 Relay]

From: David Heidelberg <david@ixit.cz>

FTS support SLPI and AP mode, introduce mode-switch GPIO to switch between
those two. Currently we can handle only full power AP mode, so we just
keep the AP on.

Useful for devices like Pixel 3 (blueline), Pixel 4a (sunfish),
Xiaomi Mi 8 (dipper), and many others.

Based on work of Petr Hodina <petr.hodina@protonmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/input/touchscreen/stmfts.c | 407 +++++++++++++++++++++++++++++++++----
 1 file changed, 366 insertions(+), 41 deletions(-)

diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
index 972687797f826..019945f64c48b 100644
--- a/drivers/input/touchscreen/stmfts.c
+++ b/drivers/input/touchscreen/stmfts.c
@@ -1,14 +1,18 @@
 // SPDX-License-Identifier: GPL-2.0
-// STMicroelectronics FTS Touchscreen device driver
-//
-// Copyright (c) 2017 Samsung Electronics Co., Ltd.
-// Copyright (c) 2017 Andi Shyti <andi@etezian.org>
+/* STMicroelectronics FTS Touchscreen device driver
+ *
+ * Copyright 2017 Samsung Electronics Co., Ltd.
+ * Copyright 2017 Andi Shyti <andi@etezian.org>
+ * Copyright David Heidelberg <david@ixit.cz>
+ * Copyright Petr Hodina <petr.hodina@protonmail.com>
+ */
 
+#include <linux/bits.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/input/mt.h>
 #include <linux/input/touchscreen.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/leds.h>
@@ -30,16 +34,21 @@
 #define STMFTS_SS_HOVER_SENSE_ON		0x95
 #define STMFTS_MS_KEY_SENSE_OFF			0x9a
 #define STMFTS_MS_KEY_SENSE_ON			0x9b
 #define STMFTS_SYSTEM_RESET			0xa0
 #define STMFTS_CLEAR_EVENT_STACK		0xa1
 #define STMFTS_FULL_FORCE_CALIBRATION		0xa2
 #define STMFTS_MS_CX_TUNING			0xa3
 #define STMFTS_SS_CX_TUNING			0xa4
+#define STMFTS5_SET_SCAN_MODE			0xa0
+
+/* FTS5 scan mode commands */
+#define STMFTS5_SCAN_MODE_ACTIVE		0x00
+#define STMFTS5_SCAN_ACTIVE_MULTI_TOUCH		BIT(0)
 
 /* events */
 #define STMFTS_EV_NO_EVENT			0x00
 #define STMFTS_EV_MULTI_TOUCH_DETECTED		0x02
 #define STMFTS_EV_MULTI_TOUCH_ENTER		0x03
 #define STMFTS_EV_MULTI_TOUCH_LEAVE		0x04
 #define STMFTS_EV_MULTI_TOUCH_MOTION		0x05
 #define STMFTS_EV_HOVER_ENTER			0x07
@@ -47,22 +56,48 @@
 #define STMFTS_EV_HOVER_MOTION			0x09
 #define STMFTS_EV_KEY_STATUS			0x0e
 #define STMFTS_EV_ERROR				0x0f
 #define STMFTS_EV_CONTROLLER_READY		0x10
 #define STMFTS_EV_SLEEP_OUT_CONTROLLER_READY	0x11
 #define STMFTS_EV_STATUS			0x16
 #define STMFTS_EV_DEBUG				0xdb
 
+/*
+ * FTS5 events: the event ID is in the high nibble of event[0], the low
+ * nibble carries additional payload (bits 5:4 of the touch major axis for
+ * touch events), so it must be masked before comparing.
+ */
+#define STMFTS5_EV_CONTROLLER_READY		0x03
+#define STMFTS5_EV_MULTI_TOUCH_ENTER		0x10
+#define STMFTS5_EV_MULTI_TOUCH_MOTION		0x20
+#define STMFTS5_EV_MULTI_TOUCH_LEAVE		0x30
+#define STMFTS5_EV_STATUS_UPDATE		0x40
+#define STMFTS5_EV_USER_REPORT			0x50
+#define STMFTS5_EV_DEBUG			0xe0
+#define STMFTS5_EV_ERROR			0xf0
+
 /* multi touch related event masks */
 #define STMFTS_MASK_EVENT_ID			0x0f
 #define STMFTS_MASK_TOUCH_ID			0xf0
 #define STMFTS_MASK_LEFT_EVENT			0x0f
 #define STMFTS_MASK_X_MSB			0x0f
 #define STMFTS_MASK_Y_LSB			0xf0
+#define STMFTS5_MASK_EVENT_ID			0xf0
+#define STMFTS5_MASK_TOUCH_TYPE			0x0f
+#define STMFTS5_MASK_MAJOR_MSB			0x0c
+#define STMFTS5_MASK_MINOR_MSB			0xc0
+
+/* touch type classifications */
+#define STMFTS_TOUCH_TYPE_INVALID		0x00
+#define STMFTS_TOUCH_TYPE_FINGER		0x01
+#define STMFTS_TOUCH_TYPE_GLOVE			0x02
+#define STMFTS_TOUCH_TYPE_STYLUS		0x03
+#define STMFTS_TOUCH_TYPE_PALM			0x04
+#define STMFTS_TOUCH_TYPE_HOVER			0x05
 
 /* key related event masks */
 #define STMFTS_MASK_KEY_NO_TOUCH		0x00
 #define STMFTS_MASK_KEY_MENU			0x01
 #define STMFTS_MASK_KEY_BACK			0x02
 
 #define STMFTS_EVENT_SIZE	8
 #define STMFTS_STACK_DEPTH	32
@@ -71,19 +106,22 @@
 #define STMFTS_DEV_NAME		"stmfts"
 
 static const struct regulator_bulk_data stmfts_supplies[] = {
 	{ .supply = "vdd" },
 	{ .supply = "avdd" },
 };
 
 struct stmfts_data {
+	const struct stmfts_chip_ops *ops;
+
 	struct i2c_client *client;
 	struct input_dev *input;
 	struct gpio_desc *reset_gpio;
+	struct gpio_desc *mode_switch_gpio;
 	struct led_classdev led_cdev;
 	struct mutex mutex;
 
 	struct touchscreen_properties prop;
 
 	struct regulator_bulk_data *supplies;
 
 	/*
@@ -100,19 +138,29 @@ struct stmfts_data {
 
 	u8 data[STMFTS_DATA_MAX_SIZE];
 
 	struct completion cmd_done;
 
 	bool use_key;
 	bool led_status;
 	bool hover_enabled;
+	bool stylus_enabled;
 	bool running;
 };
 
+struct stmfts_chip_ops {
+	int  (*configure)(struct stmfts_data *sdata);
+	int  (*setup_input)(struct stmfts_data *sdata);
+	void (*parse_events)(struct stmfts_data *sdata);
+	int  (*set_scan)(struct stmfts_data *sdata, bool enable);
+	int  (*set_hover)(struct stmfts_data *sdata, bool enable);
+	int  (*runtime_resume)(struct stmfts_data *sdata);
+};
+
 static int stmfts_brightness_set(struct led_classdev *led_cdev,
 				 enum led_brightness value)
 {
 	struct stmfts_data *sdata = container_of(led_cdev,
 					struct stmfts_data, led_cdev);
 	int err;
 
 	if (value != sdata->led_status && sdata->ledvdd) {
@@ -165,16 +213,17 @@ static int stmfts_read_events(struct stmfts_data *sdata)
 
 	ret = i2c_transfer(sdata->client->adapter, msgs, ARRAY_SIZE(msgs));
 	if (ret < 0)
 		return ret;
 
 	return ret == ARRAY_SIZE(msgs) ? 0 : -EIO;
 }
 
+/* FTS4 event handling functions */
 static void stmfts_report_contact_event(struct stmfts_data *sdata,
 					const u8 event[])
 {
 	u8 slot_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
 	u16 x = event[1] | ((event[2] & STMFTS_MASK_X_MSB) << 8);
 	u16 y = (event[2] >> 4) | (event[3] << 4);
 	u8 maj = event[4];
 	u8 min = event[5];
@@ -200,16 +249,107 @@ static void stmfts_report_contact_release(struct stmfts_data *sdata,
 	u8 slot_id = (event[0] & STMFTS_MASK_TOUCH_ID) >> 4;
 
 	input_mt_slot(sdata->input, slot_id);
 	input_mt_report_slot_inactive(sdata->input);
 
 	input_sync(sdata->input);
 }
 
+/* FTS5 event handling functions */
+static void stmfts5_report_contact_event(struct stmfts_data *sdata,
+					 const u8 event[])
+{
+	/*
+	 * FTS5 touch event format:
+	 * event[0] = event ID (high nibble) | major bits 5:4 (bits 3:2)
+	 * event[1] = touch ID (high nibble) | touch type (low nibble)
+	 * event[2] = X bits 7:0
+	 * event[3] = Y bits 3:0 (high nibble) | X bits 11:8 (low nibble)
+	 * event[4] = Y bits 11:4
+	 * event[5] = pressure
+	 * event[6] = major bits 3:0 (high nibble) | minor bits 3:0 (low nibble)
+	 * event[7] = minor bits 5:4 (bits 7:6)
+	 */
+	u8 touch_id = (event[1] & STMFTS_MASK_TOUCH_ID) >> 4;
+	u8 touch_type = event[1] & STMFTS5_MASK_TOUCH_TYPE;
+	u16 x = ((event[3] & STMFTS_MASK_X_MSB) << 8) | event[2];
+	u16 y = (event[4] << 4) | ((event[3] & STMFTS_MASK_Y_LSB) >> 4);
+	u8 area = event[5];
+	u8 maj = ((event[0] & STMFTS5_MASK_MAJOR_MSB) << 2) | (event[6] >> 4);
+	u8 min = ((event[7] & STMFTS5_MASK_MINOR_MSB) >> 2) | (event[6] & 0x0f);
+	/* Distance is 0 for touching, max for hovering */
+	int distance = 0;
+	unsigned int tool;
+
+	switch (touch_type) {
+	case STMFTS_TOUCH_TYPE_STYLUS:
+		if (sdata->stylus_enabled) {
+			tool = MT_TOOL_PEN;
+			break;
+		}
+		fallthrough; /* Report as finger if stylus not enabled */
+
+	case STMFTS_TOUCH_TYPE_FINGER:
+	case STMFTS_TOUCH_TYPE_GLOVE:
+		tool = MT_TOOL_FINGER;
+		break;
+
+	case STMFTS_TOUCH_TYPE_PALM:
+		/* Palm touch - report but can be filtered by userspace */
+		tool = MT_TOOL_PALM;
+		break;
+
+	case STMFTS_TOUCH_TYPE_HOVER:
+		tool = MT_TOOL_FINGER;
+		distance = 255;
+		break;
+
+	case STMFTS_TOUCH_TYPE_INVALID:
+	default:
+		dev_warn(&sdata->client->dev,
+			 "invalid touch type %d for slot %d\n",
+			 touch_type, touch_id);
+		return;
+	}
+
+	if (touch_type == STMFTS_TOUCH_TYPE_HOVER) {
+		area = 0;
+	} else if (!area) {
+		/*
+		 * Should not happen for contact events. Set minimum pressure
+		 * to prevent touch from being dropped.
+		 */
+		dev_warn_once(&sdata->client->dev,
+			      "zero pressure on contact event, slot %d\n",
+			      touch_id);
+		area = 1;
+	}
+
+	input_mt_slot(sdata->input, touch_id);
+	input_mt_report_slot_state(sdata->input, tool, true);
+
+	input_report_abs(sdata->input, ABS_MT_POSITION_X, x);
+	input_report_abs(sdata->input, ABS_MT_POSITION_Y, y);
+	input_report_abs(sdata->input, ABS_MT_TOUCH_MAJOR, maj);
+	input_report_abs(sdata->input, ABS_MT_TOUCH_MINOR, min);
+	input_report_abs(sdata->input, ABS_MT_PRESSURE, area);
+	input_report_abs(sdata->input, ABS_MT_DISTANCE, distance);
+}
+
+static void stmfts5_report_contact_release(struct stmfts_data *sdata,
+					   const u8 event[])
+{
+	/* FTM5 format: touch ID is in high 4 bits of event[1] */
+	u8 touch_id = (event[1] & STMFTS_MASK_TOUCH_ID) >> 4;
+
+	input_mt_slot(sdata->input, touch_id);
+	input_mt_report_slot_inactive(sdata->input);
+}
+
 static void stmfts_report_hover_event(struct stmfts_data *sdata,
 				      const u8 event[])
 {
 	u16 x = (event[2] << 4) | (event[4] >> 4);
 	u16 y = (event[3] << 4) | (event[4] & STMFTS_MASK_Y_LSB);
 	u8 z = event[5];
 
 	input_report_abs(sdata->input, ABS_X, x);
@@ -292,29 +432,76 @@ static void stmfts_parse_events(struct stmfts_data *sdata)
 
 		default:
 			dev_err(&sdata->client->dev,
 				"unknown event %#02x\n", event[0]);
 		}
 	}
 }
 
+static void stmfts5_parse_events(struct stmfts_data *sdata)
+{
+	for (int i = 0; i < STMFTS_STACK_DEPTH; i++) {
+		u8 *event = &sdata->data[i * STMFTS_EVENT_SIZE];
+
+		switch (event[0]) {
+		case STMFTS5_EV_CONTROLLER_READY:
+			complete(&sdata->cmd_done);
+			fallthrough;
+
+		case STMFTS_EV_NO_EVENT:
+			goto sync;
+		}
+
+		switch (event[0] & STMFTS5_MASK_EVENT_ID) {
+		case STMFTS5_EV_STATUS_UPDATE:
+		case STMFTS5_EV_USER_REPORT:
+		case STMFTS5_EV_DEBUG:
+			goto sync;
+
+		case STMFTS5_EV_MULTI_TOUCH_ENTER:
+		case STMFTS5_EV_MULTI_TOUCH_MOTION:
+			stmfts5_report_contact_event(sdata, event);
+			break;
+
+		case STMFTS5_EV_MULTI_TOUCH_LEAVE:
+			stmfts5_report_contact_release(sdata, event);
+			break;
+
+		case STMFTS5_EV_ERROR:
+			dev_warn(&sdata->client->dev,
+				 "error code: 0x%x%x%x%x%x%x",
+				 event[6], event[5], event[4],
+				 event[3], event[2], event[1]);
+			break;
+
+		default:
+			dev_err(&sdata->client->dev,
+				"unknown FTS5 event %#02x\n", event[0]);
+		}
+	}
+
+sync:
+	input_mt_sync_frame(sdata->input);
+	input_sync(sdata->input);
+}
+
 static irqreturn_t stmfts_irq_handler(int irq, void *dev)
 {
 	struct stmfts_data *sdata = dev;
 	int err;
 
 	guard(mutex)(&sdata->mutex);
 
 	err = stmfts_read_events(sdata);
 	if (unlikely(err))
 		dev_err(&sdata->client->dev,
 			"failed to read events: %d\n", err);
 	else
-		stmfts_parse_events(sdata);
+		sdata->ops->parse_events(sdata);
 
 	return IRQ_HANDLED;
 }
 
 static int stmfts_command(struct stmfts_data *sdata, const u8 cmd)
 {
 	int err;
 
@@ -326,37 +513,64 @@ static int stmfts_command(struct stmfts_data *sdata, const u8 cmd)
 
 	if (!wait_for_completion_timeout(&sdata->cmd_done,
 					 msecs_to_jiffies(1000)))
 		return -ETIMEDOUT;
 
 	return 0;
 }
 
+static int stmfts_set_scan(struct stmfts_data *sdata, bool enable)
+{
+	return i2c_smbus_write_byte(sdata->client,
+				    enable ? STMFTS_MS_MT_SENSE_ON :
+					     STMFTS_MS_MT_SENSE_OFF);
+}
+
+static int stmfts_set_hover(struct stmfts_data *sdata, bool enable)
+{
+	return i2c_smbus_write_byte(sdata->client,
+				    enable ? STMFTS_SS_HOVER_SENSE_ON :
+					     STMFTS_SS_HOVER_SENSE_OFF);
+}
+
+static int stmfts5_set_scan(struct stmfts_data *sdata, bool enable)
+{
+	u8 scan_mode_cmd[3] = { STMFTS5_SET_SCAN_MODE, STMFTS5_SCAN_MODE_ACTIVE,
+				enable ? STMFTS5_SCAN_ACTIVE_MULTI_TOUCH : 0 };
+	int err;
+
+	err = i2c_master_send(sdata->client, scan_mode_cmd,
+			      sizeof(scan_mode_cmd));
+	if (err != sizeof(scan_mode_cmd))
+		return err < 0 ? err : -EIO;
+
+	return 0;
+}
+
 static int stmfts_input_open(struct input_dev *dev)
 {
 	struct stmfts_data *sdata = input_get_drvdata(dev);
 	int err;
 
 	err = pm_runtime_resume_and_get(&sdata->client->dev);
 	if (err)
 		return err;
 
-	err = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_ON);
+	err = sdata->ops->set_scan(sdata, true);
 	if (err) {
 		pm_runtime_put_sync(&sdata->client->dev);
 		return err;
 	}
 
 	scoped_guard(mutex, &sdata->mutex) {
 		sdata->running = true;
 
-		if (sdata->hover_enabled) {
-			err = i2c_smbus_write_byte(sdata->client,
-						   STMFTS_SS_HOVER_SENSE_ON);
+		if (sdata->hover_enabled && sdata->ops->set_hover) {
+			err = sdata->ops->set_hover(sdata, true);
 			if (err)
 				dev_warn(&sdata->client->dev,
 					 "failed to enable hover\n");
 		}
 	}
 
 	if (sdata->use_key) {
 		err = i2c_smbus_write_byte(sdata->client,
@@ -370,27 +584,26 @@ static int stmfts_input_open(struct input_dev *dev)
 	return 0;
 }
 
 static void stmfts_input_close(struct input_dev *dev)
 {
 	struct stmfts_data *sdata = input_get_drvdata(dev);
 	int err;
 
-	err = i2c_smbus_write_byte(sdata->client, STMFTS_MS_MT_SENSE_OFF);
+	err = sdata->ops->set_scan(sdata, false);
 	if (err)
 		dev_warn(&sdata->client->dev,
 			 "failed to disable touchscreen: %d\n", err);
 
 	scoped_guard(mutex, &sdata->mutex) {
 		sdata->running = false;
 
-		if (sdata->hover_enabled) {
-			err = i2c_smbus_write_byte(sdata->client,
-						   STMFTS_SS_HOVER_SENSE_OFF);
+		if (sdata->hover_enabled && sdata->ops->set_hover) {
+			err = sdata->ops->set_hover(sdata, false);
 			if (err)
 				dev_warn(&sdata->client->dev,
 					 "failed to disable hover: %d\n", err);
 		}
 	}
 
 	if (sdata->use_key) {
 		err = i2c_smbus_write_byte(sdata->client,
@@ -482,20 +695,18 @@ static ssize_t stmfts_sysfs_hover_enable_write(struct device *dev,
 	if (kstrtoul(buf, 0, &value))
 		return -EINVAL;
 
 	hover = !!value;
 
 	guard(mutex)(&sdata->mutex);
 
 	if (hover != sdata->hover_enabled) {
-		if (sdata->running) {
-			err = i2c_smbus_write_byte(sdata->client,
-						   value ? STMFTS_SS_HOVER_SENSE_ON :
-							   STMFTS_SS_HOVER_SENSE_OFF);
+		if (sdata->running && sdata->ops->set_hover) {
+			err = sdata->ops->set_hover(sdata, hover);
 			if (err)
 				return err;
 		}
 
 		sdata->hover_enabled = hover;
 	}
 
 	return len;
@@ -551,16 +762,20 @@ static void stmfts_reset(struct stmfts_data *sdata)
 	gpiod_set_value_cansleep(sdata->reset_gpio, 0);
 	msleep(50);
 }
 
 static int stmfts_configure(struct stmfts_data *sdata)
 {
 	int err;
 
+	err = stmfts_read_system_info(sdata);
+	if (err)
+		return err;
+
 	err = stmfts_command(sdata, STMFTS_SYSTEM_RESET);
 	if (err)
 		return err;
 
 	err = stmfts_command(sdata, STMFTS_SLEEP_OUT);
 	if (err)
 		return err;
 
@@ -596,55 +811,107 @@ static int stmfts_power_on(struct stmfts_data *sdata)
 	 * The datasheet does not specify the power on time, but considering
 	 * that the reset time is < 10ms, I sleep 20ms to be sure
 	 */
 	msleep(20);
 
 	if (sdata->reset_gpio)
 		stmfts_reset(sdata);
 
-	err = stmfts_read_system_info(sdata);
-	if (err)
-		goto err_disable_regulators;
-
 	enable_irq(sdata->client->irq);
 
 	msleep(50);
 
-	err = stmfts_configure(sdata);
+	err = sdata->ops->configure(sdata);
 	if (err)
 		goto err_disable_irq;
 
 	/*
 	 * At this point no one is using the touchscreen
 	 * and I don't really care about the return value
 	 */
 	(void)i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
 
 	return 0;
 
 err_disable_irq:
 	disable_irq(sdata->client->irq);
-err_disable_regulators:
 	regulator_bulk_disable(ARRAY_SIZE(stmfts_supplies), sdata->supplies);
 	return err;
 }
 
+static int stmfts5_configure(struct stmfts_data *sdata)
+{
+	u8 event[STMFTS_EVENT_SIZE];
+	int err;
+
+	/* Verify I2C communication */
+	err = i2c_smbus_read_i2c_block_data(sdata->client,
+					    STMFTS_READ_ALL_EVENT,
+					    sizeof(event), event);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
 static void stmfts_power_off(void *data)
 {
 	struct stmfts_data *sdata = data;
 
 	disable_irq(sdata->client->irq);
 
 	if (sdata->reset_gpio)
 		gpiod_set_value_cansleep(sdata->reset_gpio, 1);
 
 	regulator_bulk_disable(ARRAY_SIZE(stmfts_supplies), sdata->supplies);
 }
 
+static int stmfts_setup_input(struct stmfts_data *sdata)
+{
+	struct device *dev = &sdata->client->dev;
+
+	input_set_abs_params(sdata->input, ABS_MT_ORIENTATION, 0, 255, 0, 0);
+	input_set_abs_params(sdata->input, ABS_DISTANCE, 0, 255, 0, 0);
+
+	sdata->use_key = device_property_read_bool(dev, "touch-key-connected");
+	if (sdata->use_key) {
+		input_set_capability(sdata->input, EV_KEY, KEY_MENU);
+		input_set_capability(sdata->input, EV_KEY, KEY_BACK);
+	}
+
+	return input_mt_init_slots(sdata->input, STMFTS_MAX_FINGERS,
+				   INPUT_MT_DIRECT);
+}
+
+static int stmfts5_setup_input(struct stmfts_data *sdata)
+{
+	struct device *dev = &sdata->client->dev;
+
+	sdata->mode_switch_gpio = devm_gpiod_get_optional(dev, "mode-switch",
+							  GPIOD_OUT_HIGH);
+	if (IS_ERR(sdata->mode_switch_gpio))
+		return dev_err_probe(dev, PTR_ERR(sdata->mode_switch_gpio),
+				     "Failed to get GPIO 'switch'\n");
+
+	/* Set resolution for accurate calibration */
+	if (!input_abs_get_res(sdata->input, ABS_MT_POSITION_X)) {
+		input_abs_set_res(sdata->input, ABS_MT_POSITION_X, 10);
+		input_abs_set_res(sdata->input, ABS_MT_POSITION_Y, 10);
+	}
+
+	input_set_abs_params(sdata->input, ABS_MT_DISTANCE, 0, 255, 0, 0);
+
+	/* Enable stylus support if requested */
+	sdata->stylus_enabled = device_property_read_bool(dev, "stylus-enabled");
+
+	return input_mt_init_slots(sdata->input, STMFTS_MAX_FINGERS,
+				   INPUT_MT_DIRECT);
+}
+
 static int stmfts_enable_led(struct stmfts_data *sdata)
 {
 	int err;
 
 	/* get the regulator for powering the leds on */
 	sdata->ledvdd = devm_regulator_get(&sdata->client->dev, "ledvdd");
 	if (IS_ERR(sdata->ledvdd))
 		return PTR_ERR(sdata->ledvdd);
@@ -680,16 +947,18 @@ static int stmfts_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	i2c_set_clientdata(client, sdata);
 
 	sdata->client = client;
 	mutex_init(&sdata->mutex);
 	init_completion(&sdata->cmd_done);
 
+	sdata->ops = i2c_get_match_data(client);
+
 	err = devm_regulator_bulk_get_const(dev,
 					    ARRAY_SIZE(stmfts_supplies),
 					    stmfts_supplies,
 					    &sdata->supplies);
 	if (err)
 		return err;
 
 	sdata->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
@@ -707,28 +976,19 @@ static int stmfts_probe(struct i2c_client *client)
 	sdata->input->close = stmfts_input_close;
 
 	input_set_capability(sdata->input, EV_ABS, ABS_MT_POSITION_X);
 	input_set_capability(sdata->input, EV_ABS, ABS_MT_POSITION_Y);
 	touchscreen_parse_properties(sdata->input, true, &sdata->prop);
 
 	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
 	input_set_abs_params(sdata->input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
-	input_set_abs_params(sdata->input, ABS_MT_ORIENTATION, 0, 255, 0, 0);
 	input_set_abs_params(sdata->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
-	input_set_abs_params(sdata->input, ABS_DISTANCE, 0, 255, 0, 0);
-
-	sdata->use_key = device_property_read_bool(dev, "touch-key-connected");
-	if (sdata->use_key) {
-		input_set_capability(sdata->input, EV_KEY, KEY_MENU);
-		input_set_capability(sdata->input, EV_KEY, KEY_BACK);
-	}
 
-	err = input_mt_init_slots(sdata->input,
-				  STMFTS_MAX_FINGERS, INPUT_MT_DIRECT);
+	err = sdata->ops->setup_input(sdata);
 	if (err)
 		return err;
 
 	input_set_drvdata(sdata->input, sdata);
 
 	/*
 	 * stmfts_power_on expects interrupt to be disabled, but
 	 * at this point the device is still off and I do not trust
@@ -789,27 +1049,71 @@ static int stmfts_runtime_suspend(struct device *dev)
 
 	ret = i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
 	if (ret)
 		dev_warn(dev, "failed to suspend device: %d\n", ret);
 
 	return ret;
 }
 
+static int stmfts_chip_runtime_resume(struct stmfts_data *sdata)
+{
+	return i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_OUT);
+}
+
+static int stmfts5_chip_runtime_resume(struct stmfts_data *sdata)
+{
+	struct i2c_client *client = sdata->client;
+	struct device *dev = &client->dev;
+	u8 int_enable_cmd[4] = { 0xB6, 0x00, 0x2C, 0x01 };
+	int err;
+
+	err = i2c_smbus_write_byte(client, STMFTS_SLEEP_OUT);
+	if (err)
+		return err;
+
+	msleep(20);
+
+	/* Perform capacitance tuning after wakeup */
+	err = i2c_smbus_write_byte(client, STMFTS_MS_CX_TUNING);
+	if (err)
+		dev_warn(dev, "MS_CX_TUNING failed: %d\n", err);
+	msleep(20);
+
+	err = i2c_smbus_write_byte(client, STMFTS_SS_CX_TUNING);
+	if (err)
+		dev_warn(dev, "SS_CX_TUNING failed: %d\n", err);
+	msleep(20);
+
+	/* Force calibration */
+	err = i2c_smbus_write_byte(client, STMFTS_FULL_FORCE_CALIBRATION);
+	if (err)
+		dev_warn(dev, "FORCE_CALIBRATION failed: %d\n", err);
+	msleep(50);
+
+	/* Enable controller interrupts */
+	err = i2c_master_send(client, int_enable_cmd, sizeof(int_enable_cmd));
+	if (err != sizeof(int_enable_cmd))
+		return err < 0 ? err : -EIO;
+
+	msleep(20);
+
+	return 0;
+}
+
 static int stmfts_runtime_resume(struct device *dev)
 {
 	struct stmfts_data *sdata = dev_get_drvdata(dev);
-	struct i2c_client *client = sdata->client;
-	int ret;
+	int err;
 
-	ret = i2c_smbus_write_byte(client, STMFTS_SLEEP_OUT);
-	if (ret)
-		dev_err(dev, "failed to resume device: %d\n", ret);
+	err = sdata->ops->runtime_resume(sdata);
+	if (err)
+		dev_err(dev, "failed to resume device: %d\n", err);
 
-	return ret;
+	return err;
 }
 
 static int stmfts_suspend(struct device *dev)
 {
 	struct stmfts_data *sdata = dev_get_drvdata(dev);
 
 	stmfts_power_off(sdata);
 
@@ -823,26 +1127,45 @@ static int stmfts_resume(struct device *dev)
 	return stmfts_power_on(sdata);
 }
 
 static const struct dev_pm_ops stmfts_pm_ops = {
 	SYSTEM_SLEEP_PM_OPS(stmfts_suspend, stmfts_resume)
 	RUNTIME_PM_OPS(stmfts_runtime_suspend, stmfts_runtime_resume, NULL)
 };
 
+static const struct stmfts_chip_ops stmfts4_ops = {
+	.configure	= stmfts_configure,
+	.setup_input	= stmfts_setup_input,
+	.parse_events	= stmfts_parse_events,
+	.set_scan	= stmfts_set_scan,
+	.set_hover	= stmfts_set_hover,
+	.runtime_resume	= stmfts_chip_runtime_resume,
+};
+
+static const struct stmfts_chip_ops stmfts5_ops = {
+	.configure	= stmfts5_configure,
+	.setup_input	= stmfts5_setup_input,
+	.parse_events	= stmfts5_parse_events,
+	.set_scan	= stmfts5_set_scan,
+	.runtime_resume	= stmfts5_chip_runtime_resume,
+};
+
 #ifdef CONFIG_OF
 static const struct of_device_id stmfts_of_match[] = {
-	{ .compatible = "st,stmfts", },
+	{ .compatible = "st,stmfts",	.data = &stmfts4_ops },
+	{ .compatible = "st,stmfts5",	.data = &stmfts5_ops },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, stmfts_of_match);
 #endif
 
 static const struct i2c_device_id stmfts_id[] = {
-	{ .name = "stmfts" },
+	{ .name = "stmfts",	.driver_data = (kernel_ulong_t)&stmfts4_ops },
+	{ .name = "stmfts5",	.driver_data = (kernel_ulong_t)&stmfts5_ops },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, stmfts_id);
 
 static struct i2c_driver stmfts_driver = {
 	.driver = {
 		.name = STMFTS_DEV_NAME,
 		.dev_groups = stmfts_sysfs_groups,
@@ -853,10 +1176,12 @@ static struct i2c_driver stmfts_driver = {
 	.probe = stmfts_probe,
 	.remove = stmfts_remove,
 	.id_table = stmfts_id,
 };
 
 module_i2c_driver(stmfts_driver);
 
 MODULE_AUTHOR("Andi Shyti <andi.shyti@samsung.com>");
+MODULE_AUTHOR("David Heidelberg <david@ixit.cz>");
+MODULE_AUTHOR("Petr Hodina <petr.hodina@protonmail.com>");
 MODULE_DESCRIPTION("STMicroelectronics FTS Touch Screen");
 MODULE_LICENSE("GPL");

-- 
2.55.0

[PATCH v6 3/3] arm64: dts: qcom: sdm845-google: Add STM FTS touchscreen support

[David Heidelberg via B4 Relay]

From: Petr Hodina <petr.hodina@protonmail.com>

Basic touchscreen connected to second i2c bus.

Signed-off-by: Petr Hodina <petr.hodina@protonmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Co-developed-by: David Heidelberg <david@ixit.cz>
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 arch/arm64/boot/dts/qcom/sdm845-google-blueline.dts | 19 ++++++++++++++++++-
 arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi  |  2 +-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845-google-blueline.dts b/arch/arm64/boot/dts/qcom/sdm845-google-blueline.dts
index fa89be500fb85..51c835dca43f1 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-google-blueline.dts
+++ b/arch/arm64/boot/dts/qcom/sdm845-google-blueline.dts
@@ -21,17 +21,34 @@ &framebuffer0 {
 	stride = <(1080 * 4)>;
 };
 
 &i2c2 {
 	clock-frequency = <1000000>;
 
 	status = "okay";
 
-	/* ST,FTS @ 49 */
+	touchscreen@49 {
+		compatible = "st,stmfts5";
+		reg = <0x49>;
+
+		pinctrl-0 = <&touchscreen_irq_n>, <&touchscreen_reset>;
+		pinctrl-names = "default";
+
+		interrupts-extended = <&tlmm 125 IRQ_TYPE_LEVEL_LOW>;
+
+		mode-switch-gpios = <&tlmm 136 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&tlmm 99 GPIO_ACTIVE_LOW>;
+
+		avdd-supply = <&vreg_l19a_3p3>;
+		vdd-supply = <&vreg_l14a_1p8>;
+
+		touchscreen-size-x = <1080>;
+		touchscreen-size-y = <2160>;
+	};
 };
 
 &mdss_dsi0 {
 	vdda-supply = <&vdda_mipi_dsi0_1p2>;
 
 	status = "okay";
 
 	panel@0 {
diff --git a/arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi b/arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi
index 9e952f9862f24..c9db3ea50f5ed 100644
--- a/arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845-google-common.dtsi
@@ -492,17 +492,17 @@ nfc_enable_default: nfc-enable-default-state {
 
 	touchscreen_reset: ts-reset-state {
 		pins = "gpio99";
 		function = "gpio";
 		drive-strength = <8>;
 		bias-pull-up;
 	};
 
-	touchscreen_pins: ts-pins-gpio-state {
+	touchscreen_irq_n: ts-irq-n-gpio-state {
 		pins = "gpio125";
 		function = "gpio";
 		drive-strength = <2>;
 		bias-disable;
 	};
 
 	touchscreen_i2c_pins: qup-i2c2-gpio-state {
 		pins = "gpio27", "gpio28";

-- 
2.55.0

Re: [PATCH v6 1/3] dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] The `if` condition matching the `compatible` property against `st,stmfts5` incorrectly uses `const` instead of `contains: const`, breaking the conditional logic and improperly forbidding `mode-switch-gpios` for the new variant.
- [Medium] The patch contains undocumented modifications to the existing `st,stmfts` device tree example and file structure.
--

commit b15460ebf5a9b2a2c1695b3d9fb6f5007a3c46e1
Author: David Heidelberg <david@ixit.cz>

dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5
    
Introduce more recent STM FTS5 touchscreen support.

> diff --git a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
> index 64c4f24ea3dd0..3de4bc5cd3f78 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
> +++ b/Documentation/devicetree/bindings/input/touchscreen/st,stmfts.yaml
[ ... ]
> @@ -51,6 +54,17 @@ required:
>    - interrupts
>    - vdd-supply
>  
> +allOf:
> +  - $ref: touchscreen.yaml#
> +  - if:
> +      not:
> +        properties:
> +          compatible:
> +            const: st,stmfts5

[Severity: Medium]
In Device Tree json-schema representation, the compatible property evaluates
as an array of strings. Does this use of const: instead of contains: const:
incorrectly compare the array to a single string?

Since the comparison would always evaluate to false, the not condition negates
this to true, which means the then clause is always applied. This appears to
incorrectly enforce mode-switch-gpios: false for all devices, breaking the
schema validation for the new st,stmfts5 variant.

> +    then:
> +      properties:
> +        mode-switch-gpios: false
> +
>  unevaluatedProperties: false
>  
>  examples:
> @@ -64,10 +78,9 @@ examples:
>          touchscreen@49 {
>              compatible = "st,stmfts";
>              reg = <0x49>;
> -            interrupt-parent = <&gpa1>;
> -            interrupts = <1 IRQ_TYPE_LEVEL_LOW>;
> -            touchscreen-size-x = <1599>;
> -            touchscreen-size-y = <2559>;
> +            interrupts-extended = <&gpa1 1 IRQ_TYPE_LEVEL_LOW>;
> +            touchscreen-size-x = <1600>;
> +            touchscreen-size-y = <2560>;

[Severity: Medium]
Are these modifications to the existing st,stmfts example and the earlier
restructuring of the allOf block missing from the commit message?

The commit message explicitly states only that it introduces STM FTS5
touchscreen support. While migrating to interrupts-extended and changing the
touchscreen size might be valid cleanups, they are undocumented side-effects
and likely should be explicitly mentioned in the commit message to justify
the changes.

>              touch-key-connected;
>              avdd-supply = <&ldo30_reg>;
>              vdd-supply = <&ldo31_reg>;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260906-stmfts5-v6-0-50fbf6af8718@ixit.cz?part=1

Re: [PATCH v6 0/3] Input: support for STM FTS5

[David Heidelberg]

On 06/09/2026 18:33, David Heidelberg via B4 Relay wrote:
> Used on various phones. Minimal viable driver.
> 
> Includes device-tree enabling touchscreen on Pixel 3.
> Also, tested on Xiaomi Mi 8 (device-tree is not yet inside the mainline).
> 
> What is missing:
>   - switching between AP and SLPI mode (to be able to wake up phone by touch)
>   - firmware loading
>   - anything above basic touch
> 
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
Sorry for the noise, seems the wake up sequence isn't right yet, FTS5 on Mi 8 
after some time off stops working - on Pixel 3 there is kept vdd-supply 
always-on, so likely it ignores incorrect suspend.

I'll send v7 fixing the issue today.

David

Re: [PATCH v6 2/3] Input: stmfts - support FTS5

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Medium] Missing capability initialization for ABS_MT_TOOL_TYPE causes stylus and palm events to be silently dropped.

Pre-existing issues:
- [High] System resume leaves an active device in hardware sleep mode.
--

commit b210ef23e8e26cf6ac531eb08d54cae1f1a1de1d
Author: David Heidelberg <david@ixit.cz>

Input: stmfts - support FTS5

This patch adds support for the FTS5 touchscreen controller to the stmfts
driver. It introduces a mode-switch GPIO to switch between AP and SLPI modes,
and handles the new FTS5 event format.

> diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
> index 972687797f826..019945f64c48b 100644
> --- a/drivers/input/touchscreen/stmfts.c
> +++ b/drivers/input/touchscreen/stmfts.c
[ ... ]
> @@ -205,6 +254,97 @@ static void stmfts_report_contact_release(struct stmfts_data *sdata,
[ ... ]
> +static void stmfts5_report_contact_event(struct stmfts_data *sdata,
> +					 const u8 event[])
> +{
[ ... ]
> +	input_mt_slot(sdata->input, touch_id);
> +	input_mt_report_slot_state(sdata->input, tool, true);

[Severity: Medium]
Will these tool type events be silently dropped by the input core?
The driver attempts to emit tool type events (like MT_TOOL_PEN or
MT_TOOL_PALM) via input_mt_report_slot_state(), but the ABS_MT_TOOL_TYPE axis
does not seem to be registered.

[ ... ]
> @@ -623,11 +834,25 @@ static int stmfts_power_on(struct stmfts_data *sdata)
>  
>  err_disable_irq:
>  	disable_irq(sdata->client->irq);
> -err_disable_regulators:
>  	regulator_bulk_disable(ARRAY_SIZE(stmfts_supplies), sdata->supplies);
>  	return err;
>  }

[Severity: High]
This is a pre-existing issue, but does system resume leave an active device in
hardware sleep mode?

The PM core invokes the stmfts_resume() sleep callback, which unconditionally
calls stmfts_power_on(). Inside stmfts_power_on(), just above the error
cleanup path shown here, the code issues a STMFTS_SLEEP_IN command.

If the device was active (open) prior to system suspend, it appears it is
forced back into sleep mode without restoring the active scanning state (no
STMFTS_SLEEP_OUT or set_scan(true) is called). Because the PM core already
considers the device active upon return, it doesn't trigger a subsequent
pm_runtime_resume(), leaving the touchscreen unresponsive until userspace
closes and reopens the device.

[ ... ]
> @@ -640,6 +865,48 @@ static void stmfts_power_off(void *data)
[ ... ]
> +static int stmfts5_setup_input(struct stmfts_data *sdata)
> +{
[ ... ]
> +	/* Enable stylus support if requested */
> +	sdata->stylus_enabled = device_property_read_bool(dev, "stylus-enabled");
> +
> +	return input_mt_init_slots(sdata->input, STMFTS_MAX_FINGERS,
> +				   INPUT_MT_DIRECT);
> +}

[Severity: Medium]
Should the ABS_MT_TOOL_TYPE capability be initialized here?
If a stylus is supported, it seems input_set_abs_params() would be needed for
the ABS_MT_TOOL_TYPE axis so the input core doesn't filter out the events.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260906-stmfts5-v6-0-50fbf6af8718@ixit.cz?part=2