[PATCH v5 0/3] Input: support for STM FTS5

[PATCH v5 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.

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 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                 | 430 +++++++++++++++++++--
 4 files changed, 436 insertions(+), 44 deletions(-)
---
base-commit: 95d6a9ccef99117115e41e9adb271243bd5e985b
change-id: 20260214-stmfts5-b47311fbd732

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

[PATCH v5 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 v5 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 | 430 ++++++++++++++++++++++++++++++++++---
 1 file changed, 396 insertions(+), 34 deletions(-)

diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
index 972687797f826..1da113d7197e6 100644
--- a/drivers/input/touchscreen/stmfts.c
+++ b/drivers/input/touchscreen/stmfts.c
@@ -1,23 +1,27 @@
 // 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/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>
 #include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 
 /* I2C commands */
 #define STMFTS_READ_INFO			0x80
 #define STMFTS_READ_STATUS			0x84
 #define STMFTS_READ_ONE_EVENT			0x85
 #define STMFTS_READ_ALL_EVENT			0x86
@@ -30,16 +34,17 @@
 #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
 
 /* 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 +52,42 @@
 #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
 
+/* events FTS5 */
+#define STMFTS5_EV_CONTROLLER_READY		0x03
+/* FTM5 event IDs (full byte, not masked) */
+#define STMFTS5_EV_MULTI_TOUCH_ENTER		0x13
+#define STMFTS5_EV_MULTI_TOUCH_MOTION		0x23
+#define STMFTS5_EV_MULTI_TOUCH_LEAVE		0x33
+#define STMFTS5_EV_STATUS_UPDATE		0x43
+#define STMFTS5_EV_USER_REPORT			0x53
+#define STMFTS5_EV_DEBUG			0xe3
+#define STMFTS5_EV_ERROR			0xf3
+
 /* 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_TOUCH_TYPE			0x0f
+
+/* 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 +96,22 @@
 #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 +128,31 @@ 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);
+	void (*power_off)(struct stmfts_data *sdata);
+	int  (*setup_input)(struct stmfts_data *sdata);
+	int  (*input_open)(struct input_dev *dev);
+	void (*input_close)(struct input_dev *dev);
+	void (*parse_events)(struct stmfts_data *sdata);
+	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 +205,17 @@ 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 +241,114 @@ 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[])
+{
+	u8 area;
+	u8 maj;
+	u8 min;
+	/* FTM5 event format:
+	 * event[0] = event ID (0x13/0x23)
+	 * event[1] = touch type (low 4 bits) | touch ID (high 4 bits)
+	 * event[2] = X LSB
+	 * event[3] = X MSB (low 4 bits) | Y MSB (high 4 bits)
+	 * event[4] = Y LSB
+	 * event[5] = pressure
+	 * event[6] = major (low 4 bits) | minor (high 4 bits)
+	 * event[7] = minor (high 2 bits)
+	 */
+	u8 touch_id = (event[1] & STMFTS_MASK_TOUCH_ID) >> 4;
+	u8 touch_type = event[1] & STMFTS5_MASK_TOUCH_TYPE;
+	int x, y, distance;
+	unsigned int tool = MT_TOOL_FINGER;
+
+	/* Parse coordinates with better precision */
+	x = (((int)event[3] & STMFTS_MASK_X_MSB) << 8) | event[2];
+	y = ((int)event[4] << 4) | ((event[3] & STMFTS_MASK_Y_LSB) >> 4);
+
+	/* Parse pressure - ensure non-zero for active touch */
+	area = event[5];
+	if (area <= 0 && touch_type != STMFTS_TOUCH_TYPE_HOVER) {
+		/* 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;
+	}
+
+	/* Parse touch area with improved bit extraction */
+	maj = (((event[0] & 0x0C) << 2) | ((event[6] & 0xF0) >> 4));
+	min = (((event[7] & 0xC0) >> 2) | (event[6] & 0x0F));
+
+	/* Distance is 0 for touching, max for hovering */
+	distance = 0;
+
+	/* Classify touch type and set appropriate tool and parameters */
+	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;
+		area = 0;
+		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;
+	}
+
+	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 +431,72 @@ 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:
+		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;
 
@@ -326,16 +508,29 @@ 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 stmfts5_set_scan_mode(struct stmfts_data *sdata, const u8 val)
+{
+	u8 scan_mode_cmd[3] = { STMFTS5_SET_SCAN_MODE, 0x00, val };
+	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;
@@ -365,16 +560,37 @@ static int stmfts_input_open(struct input_dev *dev)
 			/* I can still use only the touch screen */
 			dev_warn(&sdata->client->dev,
 				 "failed to enable touchkey\n");
 	}
 
 	return 0;
 }
 
+static int stmfts5_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 = stmfts5_set_scan_mode(sdata, 0xff);
+	if (err) {
+		pm_runtime_put_sync(&sdata->client->dev);
+		return err;
+	}
+
+	scoped_guard(mutex, &sdata->mutex)
+		sdata->running = true;
+
+	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);
 	if (err)
 		dev_warn(&sdata->client->dev,
@@ -398,16 +614,32 @@ static void stmfts_input_close(struct input_dev *dev)
 		if (err)
 			dev_warn(&sdata->client->dev,
 				 "failed to disable touchkey: %d\n", err);
 	}
 
 	pm_runtime_put_sync(&sdata->client->dev);
 }
 
+static void stmfts5_input_close(struct input_dev *dev)
+{
+	struct stmfts_data *sdata = input_get_drvdata(dev);
+	int err;
+
+	err = stmfts5_set_scan_mode(sdata, 0x00);
+	if (err)
+		dev_warn(&sdata->client->dev,
+			 "failed to disable touchscreen: %d\n", err);
+
+	scoped_guard(mutex, &sdata->mutex)
+		sdata->running = false;
+
+	pm_runtime_put_sync(&sdata->client->dev);
+}
+
 static ssize_t stmfts_sysfs_chip_id(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
 	struct stmfts_data *sdata = dev_get_drvdata(dev);
 
 	return sysfs_emit(buf, "%#x\n", sdata->chip_id);
 }
 
@@ -482,20 +714,18 @@ 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 +781,20 @@ 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 +830,123 @@ 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 stmfts5_chip_power_off(struct stmfts_data *sdata)
+{
+	i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
+	msleep(20);
+}
+
 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);
 
+	if (sdata->ops->power_off)
+		sdata->ops->power_off(sdata);
+
 	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_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 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 +982,18 @@ 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 = of_device_get_match_data(dev);
+
 	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);
@@ -698,37 +1002,28 @@ static int stmfts_probe(struct i2c_client *client)
 				     "Failed to get GPIO 'reset'\n");
 
 	sdata->input = devm_input_allocate_device(dev);
 	if (!sdata->input)
 		return -ENOMEM;
 
 	sdata->input->name = STMFTS_DEV_NAME;
 	sdata->input->id.bustype = BUS_I2C;
-	sdata->input->open = stmfts_input_open;
-	sdata->input->close = stmfts_input_close;
+	sdata->input->open = sdata->ops->input_open;
+	sdata->input->close = sdata->ops->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 +1084,71 @@ 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);
 
@@ -824,18 +1163,39 @@ static int stmfts_resume(struct device *dev)
 }
 
 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)
 };
 
 #ifdef CONFIG_OF
+static const struct stmfts_chip_ops stmfts4_ops = {
+	.configure	= stmfts_configure,
+	.setup_input	= stmfts_setup_input,
+	.input_open	= stmfts_input_open,
+	.input_close	= stmfts_input_close,
+	.parse_events	= stmfts_parse_events,
+	.set_hover	= stmfts_set_hover,
+	.runtime_resume	= stmfts_chip_runtime_resume,
+};
+
+static const struct stmfts_chip_ops stmfts5_ops = {
+	.configure	= stmfts5_configure,
+	.power_off	= stmfts5_chip_power_off,
+	.setup_input	= stmfts5_setup_input,
+	.input_open	= stmfts5_input_open,
+	.input_close	= stmfts5_input_close,
+	.parse_events	= stmfts5_parse_events,
+	.runtime_resume	= stmfts5_chip_runtime_resume,
+};
+
 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" },
 	{ }
@@ -853,10 +1213,12 @@ 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 v5 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 9368fd6b87515..bd3b5d7b7396e 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 v5 1/3] dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Schema validation logic incorrectly disables the `mode-switch-gpios` property for all compatible strings due to a missing `contains:` keyword.
--

--- Patch [1]: [PATCH v5 1/3] dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5 ---
commit 38a7826302d5c029e7cdf3f5bbdf93b5ab26d21e
Author: David Heidelberg <david@ixit.cz>

dt-bindings: input: touchscreen: st,stmfts: Introduce STM FTS5

This commit introduces support for the more recent STM FTS5 touchscreen in
the device tree bindings. It adds the new compatible string and an optional
mode-switch-gpios property for the FTS5 variant.

> 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: Low]
Does this conditional logic work as intended for a string array?

Since the compatible property evaluates as a JSON array of strings in
dt-schema, comparing it directly using const: st,stmfts5 will always
evaluate to false. 

Because this is wrapped in a not: block, the overall condition becomes true
for all nodes, meaning mode-switch-gpios: false is applied unconditionally
even for the st,stmfts5 compatible.

Should this use contains: const: st,stmfts5 instead so that valid device
trees using this property are not erroneously rejected during schema checks?

> +    then:
> +      properties:
> +        mode-switch-gpios: false
> +
>  unevaluatedProperties: false

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260810-stmfts5-v5-0-0c737d929976@ixit.cz?part=1

Re: [PATCH v5 2/3] Input: stmfts - support FTS5

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 5 potential issue(s) to consider:

New issues:
- [High] Unconditional dereference of `sdata->ops` leads to NULL pointer dereference if probed via I2C board info.
- [High] The FTS5 Y-coordinate is entirely corrupted due to erroneous MSB and LSB bit shifts.
- [Medium] The power-off sequence attempts an I2C write after the chip has already been placed into hardware reset.
- [Medium] Touch Major and Minor axes are corrupted due to logic errors combining bits with the constant Event ID.

Pre-existing issues:
- [High] The touchscreen is left in a sleep state after system resume if it was active prior to suspend.
--

--- Patch [2]: [PATCH v5 2/3] Input: stmfts - support FTS5 ---
commit 8851d4460d3a4355e8954e1dd8b5a724d25fb3be
Author: David Heidelberg <david@ixit.cz>
Subject: Input: stmfts - support FTS5

This commit adds support for FTS5 touchscreens to the stmfts driver. It
introduces a mode-switch GPIO for SLPI and AP modes, currently only handling
full power AP mode.

> diff --git a/drivers/input/touchscreen/stmfts.c b/drivers/input/touchscreen/stmfts.c
> index 972687797f826..1da113d7197e6 100644
> --- a/drivers/input/touchscreen/stmfts.c
> +++ b/drivers/input/touchscreen/stmfts.c

[ ... ]

> @@ -205,6 +246,104 @@ static void stmfts_report_contact_release(struct stmfts_data *sdata,
>  	input_sync(sdata->input);
>  }
>  
> +/* FTS5 event handling functions */
> +static void stmfts5_report_contact_event(struct stmfts_data *sdata,
> +					 const u8 event[])
> +{
[ ... ]
> +	/* Parse coordinates with better precision */
> +	x = (((int)event[3] & STMFTS_MASK_X_MSB) << 8) | event[2];
> +	y = ((int)event[4] << 4) | ((event[3] & STMFTS_MASK_Y_LSB) >> 4);

[Severity: High]
Does this bitwise logic for the Y coordinate scramble the value?

According to the comment above this code, event[4] is the 8-bit Y LSB, and
event[3] contains the 4-bit Y MSB. By shifting event[4] up by 4 and event[3]
down by 4, this appears to treat the 8-bit LSB as the most significant bits
and the 4-bit MSB as the least significant bits.

Should this be (((int)event[3] & STMFTS_MASK_Y_LSB) << 4) | event[4] instead?

> +
> +	/* Parse pressure - ensure non-zero for active touch */
> +	area = event[5];
[ ... ]
> +
> +	/* Parse touch area with improved bit extraction */
> +	maj = (((event[0] & 0x0C) << 2) | ((event[6] & 0xF0) >> 4));
> +	min = (((event[7] & 0xC0) >> 2) | (event[6] & 0x0F));

[Severity: Medium]
Is it intentional to use event[0] to calculate maj?

event[0] holds the event ID (like STMFTS5_EV_MULTI_TOUCH_ENTER which is
0x13). For valid contact events, event[0] & 0x0C will always be zero,
meaning maj only captures the upper 4 bits of event[6].

Does this result in malformed touch area statistics being reported?

[ ... ]

> @@ -601,15 +835,11 @@ static int stmfts_power_on(struct stmfts_data *sdata)
>  	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;

[Severity: High]
This is a pre-existing issue, but does stmfts_power_on() unintentionally
leave the touchscreen dead after a system resume if it was active before
suspend?

When resuming, the device is powered on and unconditionally put to sleep
with STMFTS_SLEEP_IN at the end of stmfts_power_on():

        /*
         * 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);

Because the PM core still considers the device RPM_ACTIVE from before the
suspend, it will not automatically invoke stmfts_runtime_resume(). Thus,
STMFTS_SLEEP_OUT is never sent and the hardware remains unresponsive until
userspace closes and reopens the device.

[ ... ]

> @@ -637,9 +887,61 @@ static void stmfts_power_off(void *data)
>  	if (sdata->reset_gpio)
>  		gpiod_set_value_cansleep(sdata->reset_gpio, 1);
>  
> +	if (sdata->ops->power_off)
> +		sdata->ops->power_off(sdata);

[Severity: Medium]
Will this cause an I2C transaction timeout?

By asserting the reset GPIO to 1 just before calling
sdata->ops->power_off(), the chip is placed into hardware reset.

When stmfts5_chip_power_off() immediately tries to send the
STMFTS_SLEEP_IN I2C command:

static void stmfts5_chip_power_off(struct stmfts_data *sdata)
{
        i2c_smbus_write_byte(sdata->client, STMFTS_SLEEP_IN);
        msleep(20);
}

The unresponsive chip would likely NACK the transfer or cause a bus
timeout since it is held in reset.

[ ... ]

> @@ -685,6 +987,8 @@ static int stmfts_probe(struct i2c_client *client)
>  	mutex_init(&sdata->mutex);
>  	init_completion(&sdata->cmd_done);
>  
> +	sdata->ops = of_device_get_match_data(dev);
> +
[ ... ]
> @@ -703,8 +1007,8 @@ static int stmfts_probe(struct i2c_client *client)
>  
>  	sdata->input->name = STMFTS_DEV_NAME;
>  	sdata->input->id.bustype = BUS_I2C;
> -	sdata->input->open = stmfts_input_open;
> -	sdata->input->close = stmfts_input_close;
> +	sdata->input->open = sdata->ops->input_open;
> +	sdata->input->close = sdata->ops->input_close;

[Severity: High]
What happens if this driver is instantiated via I2C sysfs board info?

Since dev->of_node would be NULL, of_device_get_match_data() would
return NULL. Would this cause a NULL pointer dereference when
accessing sdata->ops->input_open shortly after?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260810-stmfts5-v5-0-0c737d929976@ixit.cz?part=2