[PATCH v2] platform/x86: Add Goodix fingerprint EC mailbox transport

["Ertuğrul Topçu" <ertugtopcu0@gmail.com>]

Some Goodix fingerprint sensors are connected through an ACPI-described
embedded-controller shared-memory mailbox rather than directly through USB
or SPI.

Add a transport driver for the GXFP5130 platform interface. The driver
owns the MMIO mailbox, GPIO handshakes and IRQ. It exposes opaque mailbox
records through /dev/gxfp. Keep sensor initialization, TLS, capture and
image processing in userspace.

Restrict the raw transport to CAP_SYS_RAWIO and document the UAPI. Handle
device removal and system suspend without invalidating open file
descriptors.

Signed-off-by: Ertuğrul Topçu <ertugtopcu0@gmail.com>
---

Notes:
    Changes in v2:
    - Treat IRQ 0 as valid and always register a successfully resolved IRQ.
    - Replace mailbox handshake busy waits with fsleep().
    - Remove unverified Nuvoton-specific wording, stale comments and unused model data.

 .../ABI/testing/dev-goodix-ec-mailbox         |  22 +
 MAINTAINERS                                   |   8 +
 drivers/platform/x86/Kconfig                  |   2 +
 drivers/platform/x86/Makefile                 |   3 +
 .../platform/x86/goodix-ec-mailbox/Kconfig    |  15 +
 .../platform/x86/goodix-ec-mailbox/Makefile   |   2 +
 .../x86/goodix-ec-mailbox/goodix_ec_mailbox.h | 113 +++
 .../x86/goodix-ec-mailbox/goodix_ec_main.c    | 714 ++++++++++++++++++
 .../x86/goodix-ec-mailbox/goodix_ec_uapi.c    | 360 +++++++++
 include/uapi/linux/goodix_ec.h                |  37 +
 10 files changed, 1276 insertions(+)
 create mode 100644 Documentation/ABI/testing/dev-goodix-ec-mailbox
 create mode 100644 drivers/platform/x86/goodix-ec-mailbox/Kconfig
 create mode 100644 drivers/platform/x86/goodix-ec-mailbox/Makefile
 create mode 100644 drivers/platform/x86/goodix-ec-mailbox/goodix_ec_mailbox.h
 create mode 100644 drivers/platform/x86/goodix-ec-mailbox/goodix_ec_main.c
 create mode 100644 drivers/platform/x86/goodix-ec-mailbox/goodix_ec_uapi.c
 create mode 100644 include/uapi/linux/goodix_ec.h

diff --git a/Documentation/ABI/testing/dev-goodix-ec-mailbox b/Documentation/ABI/testing/dev-goodix-ec-mailbox
new file mode 100644
index 000000000000..11ca80a41ca7
--- /dev/null
+++ b/Documentation/ABI/testing/dev-goodix-ec-mailbox
@@ -0,0 +1,22 @@
+What:		/dev/gxfp
+Date:		July 2026
+KernelVersion:	TBD
+Contact:	Ertugrul Topcu <ertugtopcu0@gmail.com>
+Description:
+		Binary userspace interface for the ACPI Goodix EC mailbox
+		fingerprint transport. Only callers with CAP_SYS_RAWIO may open
+		the device. At most one reader may be open at a time.
+
+		A write consists of struct goodix_ec_tx_header followed by exactly
+		payload_len opaque MP payload bytes. reserved and flags must be zero.
+
+		A read returns one struct goodix_ec_record_header followed by exactly
+		len bytes. mp_type is the normalized MP type and timestamp_ns is a
+		CLOCK_MONOTONIC timestamp captured when the record entered the RX
+		queue. Records are never split across reads.
+
+		poll(2) reports POLLIN while a complete record is queued. Device
+		removal reports POLLERR | POLLHUP. System suspend reports POLLERR.
+
+		GOODIX_EC_IOCTL_FLUSH_RX discards all queued receive records.
+Users:		libfprint Goodix GXFP5130 userspace driver
diff --git a/MAINTAINERS b/MAINTAINERS
index 92a2167f1eb8..0c62071bbc1b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11109,6 +11109,14 @@ M:	Maud Spierings <maudspierings@gocontroll.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/connector/gocontroll,moduline-module-slot.yaml
 
+GOODIX EC MAILBOX FINGERPRINT TRANSPORT DRIVER
+M:	Ertugrul Topcu <ertugtopcu0@gmail.com>
+L:	platform-driver-x86@vger.kernel.org
+S:	Maintained
+F:	Documentation/ABI/testing/dev-goodix-ec-mailbox
+F:	drivers/platform/x86/goodix-ec-mailbox/
+F:	include/uapi/linux/goodix_ec.h
+
 GOODIX TOUCHSCREEN
 M:	Hans de Goede <hansg@kernel.org>
 L:	linux-input@vger.kernel.org
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 957034f39e4e..57d1311f8670 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -440,6 +440,8 @@ config FUJITSU_TABLET
 
          If you have a Fujitsu convertible or slate, say Y or M here.
 
+source "drivers/platform/x86/goodix-ec-mailbox/Kconfig"
+
 config GPD_POCKET_FAN
 	tristate "GPD Pocket Fan Controller support"
 	depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 872ac3842391..650ab67f7902 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -54,6 +54,9 @@ obj-$(CONFIG_AMILO_RFKILL)	+= amilo-rfkill.o
 obj-$(CONFIG_FUJITSU_LAPTOP)	+= fujitsu-laptop.o
 obj-$(CONFIG_FUJITSU_TABLET)	+= fujitsu-tablet.o
 
+# Goodix
+obj-$(CONFIG_GOODIX_EC_MAILBOX)	+= goodix-ec-mailbox/
+
 # GPD
 obj-$(CONFIG_GPD_POCKET_FAN)	+= gpd-pocket-fan.o
 
diff --git a/drivers/platform/x86/goodix-ec-mailbox/Kconfig b/drivers/platform/x86/goodix-ec-mailbox/Kconfig
new file mode 100644
index 000000000000..6f43b1323fa4
--- /dev/null
+++ b/drivers/platform/x86/goodix-ec-mailbox/Kconfig
@@ -0,0 +1,15 @@
+config GOODIX_EC_MAILBOX
+	tristate "Goodix fingerprint EC mailbox transport"
+	depends on X86
+	depends on ACPI
+	depends on GPIOLIB
+	help
+	  Enable transport support for Goodix fingerprint sensors connected
+	  through an ACPI-described embedded-controller shared-memory mailbox.
+
+	  The driver exposes the opaque mailbox transport through /dev/gxfp.
+	  Sensor configuration, TLS, capture and image processing remain in
+	  userspace.
+
+	  To compile this driver as a module, choose M here. The module will be
+	  called goodix_ec_mailbox.
diff --git a/drivers/platform/x86/goodix-ec-mailbox/Makefile b/drivers/platform/x86/goodix-ec-mailbox/Makefile
new file mode 100644
index 000000000000..52e5516eefb0
--- /dev/null
+++ b/drivers/platform/x86/goodix-ec-mailbox/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_GOODIX_EC_MAILBOX) += goodix_ec_mailbox.o
+goodix_ec_mailbox-y := goodix_ec_main.o goodix_ec_uapi.o
diff --git a/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_mailbox.h b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_mailbox.h
new file mode 100644
index 000000000000..6f412c46159b
--- /dev/null
+++ b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_mailbox.h
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _GOODIX_EC_H_
+#define _GOODIX_EC_H_
+
+#include <linux/gpio/consumer.h>
+#include <linux/ioport.h>
+#include <linux/kfifo.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+#define GOODIX_EC_DRIVER_NAME		"goodix-ec-mailbox"
+
+/* Shared-memory mailbox layout. */
+#define GOODIX_EC_MMIO_SIZE		0x1000
+#define GOODIX_EC_TX_OFFSET		0x000
+#define GOODIX_EC_TX_SIZE		0x0200
+#define GOODIX_EC_RX_OFFSET		0x0200
+#define GOODIX_EC_RX_SIZE		0x0e00
+#define GOODIX_EC_PACKET_ALIGNMENT	8
+
+/* EC mailbox framing. */
+#define GOODIX_EC_PACKET_TYPE		0xf0
+#define GOODIX_EC_SEQUENCE_SEED		0x8881
+
+/* MP framing. The payload is opaque to the kernel. */
+#define GOODIX_MP_HEADER_SIZE		4
+
+/* Mailbox handshake timing. */
+#define GOODIX_WRITE_DONE_PRE_US	50
+#define GOODIX_WRITE_DONE_HIGH_US	4000
+#define GOODIX_WRITE_DONE_POST_US	200
+#define GOODIX_READ_DONE_HIGH_US	50
+#define GOODIX_READ_DONE_POST_US	200
+#define GOODIX_SYNC_RX_DELAY_US		1000
+
+struct device;
+
+struct goodix_ec_header {
+	u8 type;
+	__le16 payload_len;
+	u8 checksum;
+	__le16 sequence;
+	u8 reserved[2];
+} __packed;
+
+struct goodix_mp_header {
+	u8 type;
+	__le16 payload_len;
+	u8 checksum;
+} __packed;
+
+struct goodix_device;
+
+struct goodix_model_data {
+	const char *name;
+};
+
+struct goodix_device {
+	struct device *dev;
+	struct kref refcount;
+	bool disconnected;
+	bool suspended;
+	bool irq_enabled;
+
+	void __iomem *mailbox;
+	resource_size_t mailbox_phys;
+	resource_size_t mailbox_size;
+
+	struct gpio_desc *write_done_gpio;
+	struct gpio_desc *read_done_gpio;
+	struct gpio_desc *irq_gpio;
+	int irq;
+
+	u8 *tx_buf;
+	u8 *rx_buf;
+
+	u8 *rx_reassembly;
+	size_t rx_reassembly_len;
+	size_t rx_reassembly_received;
+	u8 rx_reassembly_mp_type;
+	bool rx_reassembly_active;
+
+	u16 tx_sequence;
+	/* Serializes mailbox TX with threaded-IRQ RX access. */
+	struct mutex transfer_lock;
+
+	struct miscdevice miscdev;
+	struct kfifo rx_fifo;
+	/* Protects the RX FIFO and reader ownership state. */
+	spinlock_t rx_fifo_lock;
+	/* Serializes record-oriented read operations. */
+	struct mutex rx_read_lock;
+	wait_queue_head_t rx_wait;
+	bool rx_fifo_ready;
+	bool rx_reader_open;
+	bool misc_registered;
+
+	const struct goodix_model_data *model;
+};
+
+int goodix_ec_sync_send(struct goodix_device *gdev,
+			const u8 *tx, size_t tx_len);
+bool goodix_ec_device_get(struct goodix_device *gdev);
+void goodix_ec_device_put(struct goodix_device *gdev);
+int goodix_ec_uapi_register(struct goodix_device *gdev);
+void goodix_ec_uapi_unregister(struct goodix_device *gdev);
+
+#endif /* _GOODIX_EC_H_ */
diff --git a/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_main.c b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_main.c
new file mode 100644
index 000000000000..92f1c6f36b19
--- /dev/null
+++ b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_main.c
@@ -0,0 +1,714 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Goodix fingerprint sensors behind an EC shared-memory mailbox.
+ *
+ * The tested GXFP5130 platform exposes the fingerprint transport through
+ * ACPI-described MMIO and GPIO handshakes. The host exchanges opaque MP
+ * payloads with the device through this mailbox.
+ *
+ * Sensor protocol policy deliberately stays in userspace. This driver does
+ * not know about Goodix commands, checksums, TLS, configuration, capture, or
+ * sensor power states.
+ */
+
+#include <linux/acpi.h>
+#include <linux/align.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/gpio/consumer.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/timekeeping.h>
+#include <linux/uaccess.h>
+#include <linux/unaligned.h>
+
+#include "goodix_ec_mailbox.h"
+#include <linux/goodix_ec.h>
+
+#define GXFP5130_ACPI_HID "GXFP5130"
+
+static void goodix_ec_device_release(struct kref *refcount)
+{
+	struct goodix_device *gdev =
+		container_of(refcount, struct goodix_device, refcount);
+
+	kfree(gdev);
+}
+
+bool goodix_ec_device_get(struct goodix_device *gdev)
+{
+	return kref_get_unless_zero(&gdev->refcount);
+}
+
+void goodix_ec_device_put(struct goodix_device *gdev)
+{
+	kref_put(&gdev->refcount, goodix_ec_device_release);
+}
+
+static void goodix_ec_device_put_action(void *data)
+{
+	goodix_ec_device_put(data);
+}
+
+/* EC mailbox transport. */
+
+struct goodix_ec_acpi_gpio_state {
+	unsigned int gpio_count;
+	int irq_index;
+	int done_index[2];
+	u8 done_polarity[2];
+	unsigned int done_count;
+};
+
+static int goodix_ec_acpi_gpio_resource(struct acpi_resource *resource,
+					void *context)
+{
+	struct goodix_ec_acpi_gpio_state *state = context;
+	struct acpi_resource_gpio *gpio;
+	unsigned int index;
+
+	if (resource->type != ACPI_RESOURCE_TYPE_GPIO)
+		return 0;
+
+	gpio = &resource->data.gpio;
+	index = state->gpio_count++;
+	if (!gpio->pin_table_length)
+		return 0;
+
+	if (gpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT) {
+		if (state->irq_index < 0)
+			state->irq_index = index;
+	} else if (gpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_IO &&
+		   state->done_count < ARRAY_SIZE(state->done_index)) {
+		state->done_index[state->done_count] = index;
+		state->done_polarity[state->done_count] = gpio->polarity;
+		state->done_count++;
+	}
+
+	return 0;
+}
+
+static int goodix_ec_add_gpio_mappings(struct device *dev)
+{
+	struct goodix_ec_acpi_gpio_state state = {
+		.irq_index = -1,
+		.done_index = { -1, -1 },
+	};
+	struct acpi_gpio_mapping *mappings;
+	struct acpi_gpio_params *params;
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	LIST_HEAD(resources);
+	bool active_low;
+	int ret;
+
+	if (!adev)
+		return -ENODEV;
+
+	ret = acpi_dev_get_resources(adev, &resources,
+				     goodix_ec_acpi_gpio_resource, &state);
+	acpi_dev_free_resource_list(&resources);
+	if (ret <= 0)
+		return ret < 0 ? ret : -ENOENT;
+	if (state.irq_index < 0 || state.done_count != 2)
+		return dev_err_probe(dev, -ENOENT,
+				     "ACPI _CRS does not describe one IRQ and two done GPIOs\n");
+	if (state.done_polarity[0] != state.done_polarity[1])
+		return dev_err_probe(dev, -EINVAL,
+				     "ACPI done GPIO polarities differ\n");
+
+	active_low = state.done_polarity[0] != 0;
+	params = devm_kcalloc(dev, 3, sizeof(*params), GFP_KERNEL);
+	mappings = devm_kcalloc(dev, 4, sizeof(*mappings), GFP_KERNEL);
+	if (!params || !mappings)
+		return -ENOMEM;
+
+	params[0].crs_entry_index = state.irq_index;
+	params[0].line_index = 0;
+	params[0].active_low = false;
+	mappings[0].name = "irq-gpios";
+	mappings[0].data = &params[0];
+	mappings[0].size = 1;
+
+	params[1].crs_entry_index = state.done_index[0];
+	params[1].line_index = 0;
+	params[1].active_low = active_low;
+	mappings[1].name = "write-done-gpios";
+	mappings[1].data = &params[1];
+	mappings[1].size = 1;
+
+	params[2].crs_entry_index = state.done_index[1];
+	params[2].line_index = 0;
+	params[2].active_low = active_low;
+	mappings[2].name = "read-done-gpios";
+	mappings[2].data = &params[2];
+	mappings[2].size = 1;
+
+	ret = devm_acpi_dev_add_driver_gpios(dev, mappings);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to install ACPI GPIO mappings\n");
+
+	dev_dbg(dev,
+		"ACPI GPIO mappings: irq=%d write-done=%d read-done=%d active-low=%u\n",
+		state.irq_index, state.done_index[0], state.done_index[1],
+		active_low);
+	return 0;
+}
+
+static int goodix_ec_get_gpio(struct goodix_device *gdev,
+			      struct gpio_desc **gpio,
+			      const char *name,
+			      enum gpiod_flags flags)
+{
+	*gpio = devm_gpiod_get(gdev->dev, name, flags);
+	if (IS_ERR(*gpio))
+		return dev_err_probe(gdev->dev, PTR_ERR(*gpio),
+				     "failed to acquire %s GPIO\n", name);
+
+	if (!*gpio)
+		return dev_err_probe(gdev->dev, -ENODEV,
+				     "%s GPIO missing\n", name);
+
+	return 0;
+}
+
+static void goodix_ec_mmio_write_tx(struct goodix_device *gdev, size_t len)
+{
+	size_t offset;
+
+	for (offset = 0; offset < len; offset += sizeof(u64)) {
+		u64 value = get_unaligned_le64(gdev->tx_buf + offset);
+
+		writeq(value, gdev->mailbox + GOODIX_EC_TX_OFFSET + offset);
+	}
+
+	/* Publish every qword before asserting the write-done doorbell. */
+	wmb();
+}
+
+static void goodix_ec_mmio_read_rx(struct goodix_device *gdev)
+{
+	size_t offset;
+
+	for (offset = 0; offset < GOODIX_EC_RX_SIZE; offset += sizeof(u64)) {
+		u64 value = readq(gdev->mailbox + GOODIX_EC_RX_OFFSET + offset);
+
+		put_unaligned_le64(value, gdev->rx_buf + offset);
+	}
+
+	/* Complete the mailbox snapshot before parsing its headers. */
+	rmb();
+}
+
+static int goodix_ec_pulse_write_done(struct goodix_device *gdev)
+{
+	if (!gdev->write_done_gpio)
+		return -ENODEV;
+
+	gpiod_set_value_cansleep(gdev->write_done_gpio, 0);
+	fsleep(GOODIX_WRITE_DONE_PRE_US);
+
+	gpiod_set_value_cansleep(gdev->write_done_gpio, 1);
+	fsleep(GOODIX_WRITE_DONE_HIGH_US);
+
+	gpiod_set_value_cansleep(gdev->write_done_gpio, 0);
+	fsleep(GOODIX_WRITE_DONE_POST_US);
+
+	return 0;
+}
+
+static int goodix_ec_pulse_read_done(struct goodix_device *gdev)
+{
+	if (!gdev->read_done_gpio)
+		return -ENODEV;
+
+	/* RX must be copied before acknowledging that the host consumed it. */
+	gpiod_set_value_cansleep(gdev->read_done_gpio, 1);
+	fsleep(GOODIX_READ_DONE_HIGH_US);
+
+	gpiod_set_value_cansleep(gdev->read_done_gpio, 0);
+	fsleep(GOODIX_READ_DONE_POST_US);
+
+	return 0;
+}
+
+static int goodix_ec_build_packet(struct goodix_device *gdev,
+				  const u8 *payload, size_t payload_len,
+				  size_t *packet_len)
+{
+	struct goodix_ec_header *header;
+	size_t total_len;
+
+	if (!gdev || !payload || !payload_len || !packet_len)
+		return -EINVAL;
+
+	if (payload_len > U16_MAX)
+		return -EOVERFLOW;
+
+	total_len = ALIGN(sizeof(*header) + payload_len,
+			  GOODIX_EC_PACKET_ALIGNMENT);
+	if (total_len > GOODIX_EC_TX_SIZE)
+		return -EMSGSIZE;
+
+	memset(gdev->tx_buf, 0, total_len);
+
+	header = (struct goodix_ec_header *)gdev->tx_buf;
+	header->type = GOODIX_EC_PACKET_TYPE;
+	header->payload_len = cpu_to_le16(payload_len);
+	header->checksum = header->type + (payload_len & 0xff) +
+			   ((payload_len >> 8) & 0xff);
+	header->sequence = cpu_to_le16(++gdev->tx_sequence);
+
+	memcpy(gdev->tx_buf + sizeof(*header), payload, payload_len);
+	*packet_len = total_len;
+
+	return 0;
+}
+
+int goodix_ec_sync_send(struct goodix_device *gdev,
+			const u8 *tx, size_t tx_len)
+{
+	size_t packet_len;
+	int ret;
+
+	ret = goodix_ec_build_packet(gdev, tx, tx_len, &packet_len);
+	if (ret)
+		return ret;
+
+	goodix_ec_mmio_write_tx(gdev, packet_len);
+
+	ret = goodix_ec_pulse_write_done(gdev);
+	if (ret)
+		return ret;
+
+	fsleep(GOODIX_SYNC_RX_DELAY_US);
+	return 0;
+}
+
+/* MP packet transport. */
+static void goodix_ec_rx_push(struct goodix_device *gdev, u8 mp_type,
+			      const u8 *payload, size_t payload_len)
+{
+	struct goodix_ec_record_header header;
+	unsigned long flags;
+	size_t required;
+
+	if (!gdev || !payload || !payload_len ||
+	    payload_len > GOODIX_EC_UAPI_RX_MAX)
+		return;
+
+	memset(&header, 0, sizeof(header));
+	header.len = payload_len;
+	header.mp_type = mp_type >> 4;
+	header.timestamp_ns = ktime_get_ns();
+	required = sizeof(header) + payload_len;
+
+	spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+	if (!gdev->rx_fifo_ready || kfifo_avail(&gdev->rx_fifo) < required) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		dev_warn_ratelimited(gdev->dev,
+				     "RX queue full; dropping %zu-byte packet\n",
+				     payload_len);
+		return;
+	}
+
+	kfifo_in(&gdev->rx_fifo, &header, sizeof(header));
+	kfifo_in(&gdev->rx_fifo, payload, payload_len);
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+	wake_up_interruptible(&gdev->rx_wait);
+}
+
+static irqreturn_t goodix_ec_irq_thread(int irq, void *data)
+{
+	struct goodix_device *gdev = data;
+	size_t chunk_len;
+	size_t remaining;
+	u16 declared_len;
+	u8 mp_type;
+	int ret = 0;
+	int ack_ret;
+
+	mutex_lock(&gdev->transfer_lock);
+
+	goodix_ec_mmio_read_rx(gdev);
+
+	/*
+	 * Continuation IRQs contain raw payload bytes without another
+	 * MP header.
+	 */
+	if (gdev->rx_reassembly_active) {
+		remaining = gdev->rx_reassembly_len -
+			    gdev->rx_reassembly_received;
+
+		chunk_len = min_t(size_t,
+				  remaining,
+				  GOODIX_EC_RX_SIZE);
+
+		memcpy(gdev->rx_reassembly +
+		       gdev->rx_reassembly_received,
+		       gdev->rx_buf,
+		       chunk_len);
+
+		gdev->rx_reassembly_received += chunk_len;
+
+		ack_ret = goodix_ec_pulse_read_done(gdev);
+		if (ack_ret)
+			ret = ack_ret;
+
+		if (!ret &&
+		    gdev->rx_reassembly_received ==
+		    gdev->rx_reassembly_len) {
+			dev_dbg(gdev->dev,
+				"RX reassembly complete: MP=0x%02x payload=%zu bytes\n",
+				 gdev->rx_reassembly_mp_type,
+				 gdev->rx_reassembly_len);
+
+			goodix_ec_rx_push(gdev,
+					  gdev->rx_reassembly_mp_type,
+					  gdev->rx_reassembly,
+					  gdev->rx_reassembly_len);
+
+			kfree(gdev->rx_reassembly);
+			gdev->rx_reassembly = NULL;
+			gdev->rx_reassembly_len = 0;
+			gdev->rx_reassembly_received = 0;
+			gdev->rx_reassembly_mp_type = 0;
+			gdev->rx_reassembly_active = false;
+		}
+
+		mutex_unlock(&gdev->transfer_lock);
+
+		if (ret)
+			dev_warn_ratelimited(gdev->dev,
+					     "IRQ %d continuation ACK failed: %d\n",
+					     irq, ret);
+
+		return IRQ_HANDLED;
+	}
+
+	mp_type = gdev->rx_buf[0];
+
+	if ((mp_type >> 4) != 0x0a &&
+	    (mp_type >> 4) != 0x0b &&
+	    (mp_type >> 4) != 0x0c) {
+		ret = -EBADMSG;
+		goto acknowledge;
+	}
+
+	if (gdev->rx_buf[3] !=
+	    gdev->rx_buf[0] +
+	    gdev->rx_buf[1] +
+	    gdev->rx_buf[2]) {
+		ret = -EBADMSG;
+		goto acknowledge;
+	}
+
+	declared_len = get_unaligned_le16(gdev->rx_buf + 1);
+
+	/* The complete payload fits in one mailbox transaction. */
+	if (declared_len <=
+	    GOODIX_EC_RX_SIZE -
+	    sizeof(struct goodix_mp_header)) {
+		goodix_ec_rx_push(gdev,
+				  mp_type,
+				  gdev->rx_buf +
+				  sizeof(struct goodix_mp_header),
+				  declared_len);
+
+		dev_dbg(gdev->dev,
+			"IRQ %d RX queued: MP=0x%02x payload=%u bytes\n",
+			irq,
+			mp_type >> 4,
+			declared_len);
+
+		goto acknowledge;
+	}
+
+	/* Reassemble payloads delivered across multiple IRQs. */
+	gdev->rx_reassembly = kmalloc(declared_len, GFP_KERNEL);
+	if (!gdev->rx_reassembly) {
+		ret = -ENOMEM;
+		goto acknowledge;
+	}
+
+	chunk_len = GOODIX_EC_RX_SIZE -
+		    sizeof(struct goodix_mp_header);
+
+	memcpy(gdev->rx_reassembly,
+	       gdev->rx_buf +
+	       sizeof(struct goodix_mp_header),
+	       chunk_len);
+
+	gdev->rx_reassembly_len = declared_len;
+	gdev->rx_reassembly_received = chunk_len;
+	gdev->rx_reassembly_mp_type = mp_type;
+	gdev->rx_reassembly_active = true;
+
+	dev_dbg(gdev->dev,
+		"RX reassembly started: MP=0x%02x total=%u first=%zu remaining=%zu\n",
+		 mp_type >> 4,
+		 declared_len,
+		 chunk_len,
+		 (size_t)declared_len - chunk_len);
+
+acknowledge:
+	ack_ret = goodix_ec_pulse_read_done(gdev);
+	if (!ret && ack_ret)
+		ret = ack_ret;
+
+	mutex_unlock(&gdev->transfer_lock);
+
+	if (ret)
+		dev_warn_ratelimited(gdev->dev,
+				     "IRQ %d RX handling failed: %d\n",
+				     irq, ret);
+
+	return IRQ_HANDLED;
+}
+
+static const struct goodix_model_data gxfp5130_model = {
+	.name = "GXFP5130",
+};
+
+/* ACPI platform driver and model selection. */
+
+static int goodix_ec_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct acpi_device_id *match;
+	struct goodix_device *gdev;
+	struct resource *resource;
+	resource_size_t mailbox_size;
+	unsigned long irq_flags;
+	unsigned int irq_type;
+	int ret;
+
+	match = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!match || !match->driver_data)
+		return -ENODEV;
+
+	gdev = kzalloc_obj(*gdev);
+	if (!gdev)
+		return -ENOMEM;
+	kref_init(&gdev->refcount);
+	ret = devm_add_action_or_reset(dev, goodix_ec_device_put_action, gdev);
+	if (ret)
+		return ret;
+
+	gdev->dev = dev;
+	gdev->model = (const struct goodix_model_data *)match->driver_data;
+	gdev->tx_sequence = GOODIX_EC_SEQUENCE_SEED;
+	mutex_init(&gdev->transfer_lock);
+	platform_set_drvdata(pdev, gdev);
+
+	gdev->mailbox = devm_platform_get_and_ioremap_resource(pdev, 0,
+							       &resource);
+	if (IS_ERR(gdev->mailbox))
+		return dev_err_probe(dev, PTR_ERR(gdev->mailbox),
+				     "failed to map EC mailbox MMIO resource\n");
+
+	mailbox_size = resource_size(resource);
+	if (mailbox_size < GOODIX_EC_MMIO_SIZE)
+		return dev_err_probe(dev, -EINVAL,
+				     "EC mailbox resource too small: %#llx\n",
+				     (unsigned long long)mailbox_size);
+
+	gdev->mailbox_phys = resource->start;
+	gdev->mailbox_size = mailbox_size;
+
+	gdev->tx_buf = devm_kzalloc(dev, GOODIX_EC_TX_SIZE, GFP_KERNEL);
+	if (!gdev->tx_buf)
+		return -ENOMEM;
+
+	gdev->rx_buf = devm_kzalloc(dev, GOODIX_EC_RX_SIZE, GFP_KERNEL);
+	if (!gdev->rx_buf)
+		return -ENOMEM;
+
+	ret = goodix_ec_add_gpio_mappings(dev);
+	if (ret)
+		return ret;
+
+	ret = goodix_ec_get_gpio(gdev, &gdev->write_done_gpio,
+				 "write-done", GPIOD_OUT_LOW);
+	if (ret)
+		return ret;
+
+	ret = goodix_ec_get_gpio(gdev, &gdev->read_done_gpio,
+				 "read-done", GPIOD_OUT_LOW);
+	if (ret)
+		return ret;
+
+	ret = goodix_ec_get_gpio(gdev, &gdev->irq_gpio,
+				 "irq", GPIOD_IN);
+	if (ret)
+		return ret;
+
+	gdev->irq = gpiod_to_irq(gdev->irq_gpio);
+	if (gdev->irq < 0)
+		return dev_err_probe(dev, gdev->irq,
+				     "failed to map IRQ GPIO to an IRQ\n");
+
+	irq_type = irq_get_trigger_type(gdev->irq);
+	if (irq_type == IRQ_TYPE_NONE) {
+		ret = irq_set_irq_type(gdev->irq, IRQ_TYPE_LEVEL_HIGH);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "failed to set level-high IRQ trigger\n");
+		irq_type = IRQ_TYPE_LEVEL_HIGH;
+	}
+
+	dev_info(dev, "bound %s: mailbox=%pa size=%#llx irq=%d\n",
+		 gdev->model->name, &gdev->mailbox_phys,
+		 (unsigned long long)gdev->mailbox_size, gdev->irq);
+
+	irq_flags = IRQF_ONESHOT | IRQF_NO_AUTOEN;
+	ret = devm_request_threaded_irq(dev,
+					gdev->irq,
+					NULL,
+					goodix_ec_irq_thread,
+					irq_flags,
+					dev_name(dev),
+					gdev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to request IRQ %d\n",
+				     gdev->irq);
+
+	dev_dbg(dev, "IRQ %d registered: flags=%#lx trigger=%#x\n",
+		gdev->irq, irq_flags, irq_type);
+
+	ret = goodix_ec_uapi_register(gdev);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to register userspace interface\n");
+
+	enable_irq(gdev->irq);
+	gdev->irq_enabled = true;
+	dev_info(dev, "IRQ %d armed\n", gdev->irq);
+
+	dev_info(dev, "EC mailbox transport ready\n");
+	return 0;
+}
+
+static void goodix_ec_remove(struct platform_device *pdev)
+{
+	struct goodix_device *gdev = platform_get_drvdata(pdev);
+
+	if (!gdev)
+		return;
+
+	WRITE_ONCE(gdev->disconnected, true);
+	if (gdev->irq_enabled) {
+		disable_irq(gdev->irq);
+		synchronize_irq(gdev->irq);
+		gdev->irq_enabled = false;
+	}
+
+	goodix_ec_uapi_unregister(gdev);
+	mutex_lock(&gdev->transfer_lock);
+	kfree(gdev->rx_reassembly);
+	gdev->rx_reassembly = NULL;
+	gdev->rx_reassembly_len = 0;
+	gdev->rx_reassembly_received = 0;
+	gdev->rx_reassembly_active = false;
+
+	if (gdev->write_done_gpio)
+		gpiod_set_value_cansleep(gdev->write_done_gpio, 0);
+	if (gdev->read_done_gpio)
+		gpiod_set_value_cansleep(gdev->read_done_gpio, 0);
+	mutex_unlock(&gdev->transfer_lock);
+
+	dev_info(gdev->dev, "%s detached\n", gdev->model->name);
+}
+
+static int goodix_ec_suspend(struct device *dev)
+{
+	struct goodix_device *gdev = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	if (!gdev || READ_ONCE(gdev->disconnected))
+		return 0;
+
+	WRITE_ONCE(gdev->suspended, true);
+	wake_up_interruptible_all(&gdev->rx_wait);
+	if (gdev->irq_enabled) {
+		disable_irq(gdev->irq);
+		synchronize_irq(gdev->irq);
+		gdev->irq_enabled = false;
+	}
+
+	mutex_lock(&gdev->transfer_lock);
+	gpiod_set_value_cansleep(gdev->write_done_gpio, 0);
+	gpiod_set_value_cansleep(gdev->read_done_gpio, 0);
+	kfree(gdev->rx_reassembly);
+	gdev->rx_reassembly = NULL;
+	gdev->rx_reassembly_len = 0;
+	gdev->rx_reassembly_received = 0;
+	gdev->rx_reassembly_active = false;
+	mutex_unlock(&gdev->transfer_lock);
+
+	spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+	if (gdev->rx_fifo_ready)
+		kfifo_reset(&gdev->rx_fifo);
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+	return 0;
+}
+
+static int goodix_ec_resume(struct device *dev)
+{
+	struct goodix_device *gdev = dev_get_drvdata(dev);
+
+	if (!gdev || READ_ONCE(gdev->disconnected))
+		return 0;
+
+	gpiod_set_value_cansleep(gdev->write_done_gpio, 0);
+	gpiod_set_value_cansleep(gdev->read_done_gpio, 0);
+	if (!gdev->irq_enabled) {
+		enable_irq(gdev->irq);
+		gdev->irq_enabled = true;
+	}
+	/* Permit new writes only after the receive path is armed. */
+	WRITE_ONCE(gdev->suspended, false);
+	wake_up_interruptible_all(&gdev->rx_wait);
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(goodix_ec_pm_ops, goodix_ec_suspend,
+				goodix_ec_resume);
+
+static const struct acpi_device_id goodix_ec_acpi_match[] = {
+	{
+		.id = GXFP5130_ACPI_HID,
+		.driver_data = (kernel_ulong_t)&gxfp5130_model,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, goodix_ec_acpi_match);
+
+static struct platform_driver goodix_ec_driver = {
+	.probe = goodix_ec_probe,
+	.remove = goodix_ec_remove,
+	.driver = {
+		.name = GOODIX_EC_DRIVER_NAME,
+		.acpi_match_table = ACPI_PTR(goodix_ec_acpi_match),
+		.pm = pm_sleep_ptr(&goodix_ec_pm_ops),
+	},
+};
+module_platform_driver(goodix_ec_driver);
+
+MODULE_AUTHOR("Ertugrul Topcu <ertugtopcu0@gmail.com>");
+MODULE_DESCRIPTION("Goodix fingerprint sensors over an EC mailbox");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_uapi.c b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_uapi.c
new file mode 100644
index 000000000000..d2f075acb481
--- /dev/null
+++ b/drivers/platform/x86/goodix-ec-mailbox/goodix_ec_uapi.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/unaligned.h>
+
+#include "goodix_ec_mailbox.h"
+#include <linux/goodix_ec.h>
+
+#define GOODIX_EC_RX_FIFO_BYTES (256u * 1024u)
+
+static bool goodix_ec_rx_ready(struct goodix_device *gdev)
+{
+	unsigned long flags;
+	bool ready;
+
+	spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+	ready = gdev->rx_fifo_ready && !kfifo_is_empty(&gdev->rx_fifo);
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+	return ready;
+}
+
+static int goodix_ec_uapi_open(struct inode *inode, struct file *file)
+{
+	struct miscdevice *misc = file->private_data;
+	struct goodix_device *gdev =
+		container_of(misc, struct goodix_device, miscdev);
+	unsigned long flags;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+	if (!goodix_ec_device_get(gdev))
+		return -ENODEV;
+	if (READ_ONCE(gdev->disconnected)) {
+		goodix_ec_device_put(gdev);
+		return -ENODEV;
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+		if (!gdev->rx_fifo_ready) {
+			spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+			goodix_ec_device_put(gdev);
+			return -ENODEV;
+		}
+
+		if (gdev->rx_reader_open) {
+			spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+			goodix_ec_device_put(gdev);
+			return -EBUSY;
+		}
+
+		gdev->rx_reader_open = true;
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+	}
+
+	file->private_data = gdev;
+	return 0;
+}
+
+static int goodix_ec_uapi_release(struct inode *inode, struct file *file)
+{
+	struct goodix_device *gdev = file->private_data;
+	unsigned long flags;
+
+	if (gdev && (file->f_mode & FMODE_READ)) {
+		spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+		gdev->rx_reader_open = false;
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+	}
+	if (gdev)
+		goodix_ec_device_put(gdev);
+
+	return 0;
+}
+
+static ssize_t goodix_ec_uapi_write(struct file *file,
+				    const char __user *user_buffer,
+				    size_t count, loff_t *position)
+{
+	struct goodix_device *gdev = file->private_data;
+	struct goodix_ec_tx_header header;
+	u8 *mp_packet;
+	size_t required;
+	int ret;
+
+	if (!gdev || !user_buffer || READ_ONCE(gdev->disconnected))
+		return -ENODEV;
+
+	if (count < sizeof(header))
+		return -EINVAL;
+
+	if (copy_from_user(&header, user_buffer, sizeof(header)))
+		return -EFAULT;
+
+	if (header.payload_len > GOODIX_EC_UAPI_TX_MAX)
+		return -EMSGSIZE;
+	if (header.reserved || header.flags)
+		return -EINVAL;
+
+	required = sizeof(header) + header.payload_len;
+	if (count != required)
+		return -EINVAL;
+
+	mp_packet = kmalloc(GOODIX_MP_HEADER_SIZE +
+			    header.payload_len, GFP_KERNEL);
+	if (!mp_packet)
+		return -ENOMEM;
+
+	mp_packet[0] = header.mp_flags;
+	put_unaligned_le16(header.payload_len, mp_packet + 1);
+	mp_packet[3] = mp_packet[0] + mp_packet[1] + mp_packet[2];
+
+	if (header.payload_len &&
+	    copy_from_user(mp_packet + sizeof(struct goodix_mp_header),
+			   user_buffer + sizeof(header),
+			   header.payload_len)) {
+		kfree(mp_packet);
+		return -EFAULT;
+	}
+
+	mutex_lock(&gdev->transfer_lock);
+	if (READ_ONCE(gdev->disconnected))
+		ret = -ENODEV;
+	else if (READ_ONCE(gdev->suspended))
+		ret = -EHOSTDOWN;
+	else
+		ret = goodix_ec_sync_send(gdev, mp_packet,
+					  sizeof(struct goodix_mp_header) +
+					  header.payload_len);
+	mutex_unlock(&gdev->transfer_lock);
+
+	kfree(mp_packet);
+
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t goodix_ec_uapi_read(struct file *file, char __user *user_buffer,
+				   size_t count, loff_t *position)
+{
+	struct goodix_device *gdev = file->private_data;
+	struct goodix_ec_record_header header;
+	unsigned long flags;
+	u8 *record;
+	size_t required;
+	int ret;
+
+	if (!gdev || !user_buffer || READ_ONCE(gdev->disconnected))
+		return -ENODEV;
+
+	ret = mutex_lock_interruptible(&gdev->rx_read_lock);
+	if (ret)
+		return ret;
+
+	for (;;) {
+		spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+
+		if (!gdev->rx_fifo_ready) {
+			spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+			ret = -ENODEV;
+			goto out_unlock;
+		}
+		if (READ_ONCE(gdev->suspended)) {
+			spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+			ret = -EHOSTDOWN;
+			goto out_unlock;
+		}
+
+		if (kfifo_len(&gdev->rx_fifo) >= sizeof(header))
+			break;
+
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			goto out_unlock;
+		}
+
+		ret = wait_event_interruptible(gdev->rx_wait,
+					       goodix_ec_rx_ready(gdev) ||
+					       !READ_ONCE(gdev->rx_fifo_ready) ||
+					       READ_ONCE(gdev->suspended));
+		if (ret)
+			goto out_unlock;
+	}
+
+	if (kfifo_out_peek(&gdev->rx_fifo, &header,
+			   sizeof(header)) != sizeof(header)) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		ret = -EIO;
+		goto out_unlock;
+	}
+
+	required = sizeof(header) + header.len;
+	if (kfifo_len(&gdev->rx_fifo) < required) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		ret = -EIO;
+		goto out_unlock;
+	}
+
+	if (count < required) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		ret = -EMSGSIZE;
+		goto out_unlock;
+	}
+
+	record = kmalloc(required, GFP_ATOMIC);
+	if (!record) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	if (kfifo_out(&gdev->rx_fifo, record, required) != required) {
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		kfree(record);
+		ret = -EIO;
+		goto out_unlock;
+	}
+
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+	if (copy_to_user(user_buffer, record, required)) {
+		kfree(record);
+		ret = -EFAULT;
+		goto out_unlock;
+	}
+
+	kfree(record);
+	ret = required;
+
+out_unlock:
+	mutex_unlock(&gdev->rx_read_lock);
+	return ret;
+}
+
+static __poll_t goodix_ec_uapi_poll(struct file *file, poll_table *wait)
+{
+	struct goodix_device *gdev = file->private_data;
+	unsigned long flags;
+	__poll_t mask = 0;
+
+	if (!gdev || READ_ONCE(gdev->disconnected))
+		return EPOLLERR;
+
+	poll_wait(file, &gdev->rx_wait, wait);
+
+	spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+	if (!gdev->rx_fifo_ready || READ_ONCE(gdev->disconnected))
+		mask = EPOLLERR | EPOLLHUP;
+	else if (READ_ONCE(gdev->suspended))
+		mask = EPOLLERR;
+	else if (!kfifo_is_empty(&gdev->rx_fifo))
+		mask = EPOLLIN | EPOLLRDNORM;
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+	return mask;
+}
+
+static long goodix_ec_uapi_ioctl(struct file *file,
+				 unsigned int command,
+				 unsigned long argument)
+{
+	struct goodix_device *gdev = file->private_data;
+	unsigned long flags;
+
+	if (!gdev || READ_ONCE(gdev->disconnected))
+		return -ENODEV;
+
+	switch (command) {
+	case GOODIX_EC_IOCTL_FLUSH_RX:
+		spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+		if (gdev->rx_fifo_ready)
+			kfifo_reset(&gdev->rx_fifo);
+		spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+static const struct file_operations goodix_ec_uapi_fops = {
+	.owner = THIS_MODULE,
+	.open = goodix_ec_uapi_open,
+	.release = goodix_ec_uapi_release,
+	.read = goodix_ec_uapi_read,
+	.write = goodix_ec_uapi_write,
+	.poll = goodix_ec_uapi_poll,
+	.unlocked_ioctl = goodix_ec_uapi_ioctl,
+	.compat_ioctl = compat_ptr_ioctl,
+	.llseek = noop_llseek,
+};
+
+int goodix_ec_uapi_register(struct goodix_device *gdev)
+{
+	int ret;
+
+	spin_lock_init(&gdev->rx_fifo_lock);
+	mutex_init(&gdev->rx_read_lock);
+	init_waitqueue_head(&gdev->rx_wait);
+
+	ret = kfifo_alloc(&gdev->rx_fifo, GOODIX_EC_RX_FIFO_BYTES, GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	gdev->rx_fifo_ready = true;
+	gdev->rx_reader_open = false;
+
+	gdev->miscdev.minor = MISC_DYNAMIC_MINOR;
+	gdev->miscdev.name = "gxfp";
+	gdev->miscdev.fops = &goodix_ec_uapi_fops;
+	gdev->miscdev.parent = gdev->dev;
+
+	ret = misc_register(&gdev->miscdev);
+	if (ret) {
+		gdev->rx_fifo_ready = false;
+		kfifo_free(&gdev->rx_fifo);
+		return ret;
+	}
+
+	gdev->misc_registered = true;
+	dev_info(gdev->dev, "userspace interface registered: /dev/gxfp\n");
+	return 0;
+}
+
+void goodix_ec_uapi_unregister(struct goodix_device *gdev)
+{
+	unsigned long flags;
+
+	if (!gdev)
+		return;
+
+	if (gdev->misc_registered) {
+		misc_deregister(&gdev->miscdev);
+		gdev->misc_registered = false;
+	}
+
+	if (!gdev->rx_fifo_ready)
+		return;
+
+	spin_lock_irqsave(&gdev->rx_fifo_lock, flags);
+	gdev->rx_fifo_ready = false;
+	gdev->rx_reader_open = false;
+	kfifo_reset(&gdev->rx_fifo);
+	spin_unlock_irqrestore(&gdev->rx_fifo_lock, flags);
+
+	wake_up_interruptible_all(&gdev->rx_wait);
+	kfifo_free(&gdev->rx_fifo);
+}
diff --git a/include/uapi/linux/goodix_ec.h b/include/uapi/linux/goodix_ec.h
new file mode 100644
index 000000000000..ff8d0d505ae7
--- /dev/null
+++ b/include/uapi/linux/goodix_ec.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_GOODIX_EC_H_
+#define _UAPI_GOODIX_EC_H_
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define GOODIX_EC_UAPI_MAGIC		'G'
+#define GOODIX_EC_UAPI_TX_MAX		500u
+#define GOODIX_EC_UAPI_RX_MAX		(128u * 1024u)
+
+/*
+ * read(2) returns one record:
+ *   struct goodix_ec_record_header
+ *   followed by len bytes of MP payload (normally one Goodix frame).
+ */
+struct goodix_ec_record_header {
+	__u32 len;
+	__u32 mp_type;
+	__u64 timestamp_ns;
+};
+
+/*
+ * write(2) accepts:
+ *   struct goodix_ec_tx_header
+ *   followed by payload_len bytes used as the MP payload.
+ */
+struct goodix_ec_tx_header {
+	__u8 mp_flags;
+	__u8 reserved;
+	__u16 payload_len;
+	__u32 flags;
+};
+
+#define GOODIX_EC_IOCTL_FLUSH_RX	_IO(GOODIX_EC_UAPI_MAGIC, 0x11)
+
+#endif /* _UAPI_GOODIX_EC_H_ */
-- 
2.55.0