From 33aff2baaac3a7444376cd6b01690a7a24f60425 Mon Sep 17 00:00:00 2001
From: Dorian Stoll <dorian.stoll@tmsp.io>
Date: Sun, 11 Dec 2022 12:00:59 +0100
Subject: [PATCH 09/41] hid: Add support for Intel Precise Touch and Stylus
Based on linux-surface/intel-precise-touch@8abe268
Signed-off-by: Dorian Stoll <dorian.stoll@tmsp.io>
Patchset: ipts
---
drivers/hid/Kconfig | 2 +
drivers/hid/Makefile | 2 +
drivers/hid/ipts/Kconfig | 14 +
drivers/hid/ipts/Makefile | 16 ++
drivers/hid/ipts/cmd.c | 61 +++++
drivers/hid/ipts/cmd.h | 60 ++++
drivers/hid/ipts/context.h | 52 ++++
drivers/hid/ipts/control.c | 486 +++++++++++++++++++++++++++++++++
drivers/hid/ipts/control.h | 126 +++++++++
drivers/hid/ipts/desc.h | 80 ++++++
drivers/hid/ipts/eds1.c | 103 +++++++
drivers/hid/ipts/eds1.h | 35 +++
drivers/hid/ipts/eds2.c | 144 ++++++++++
drivers/hid/ipts/eds2.h | 35 +++
drivers/hid/ipts/hid.c | 225 +++++++++++++++
drivers/hid/ipts/hid.h | 24 ++
drivers/hid/ipts/main.c | 126 +++++++++
drivers/hid/ipts/mei.c | 188 +++++++++++++
drivers/hid/ipts/mei.h | 66 +++++
drivers/hid/ipts/receiver.c | 250 +++++++++++++++++
drivers/hid/ipts/receiver.h | 16 ++
drivers/hid/ipts/resources.c | 131 +++++++++
drivers/hid/ipts/resources.h | 41 +++
drivers/hid/ipts/spec-data.h | 100 +++++++
drivers/hid/ipts/spec-device.h | 290 ++++++++++++++++++++
drivers/hid/ipts/spec-hid.h | 34 +++
drivers/hid/ipts/thread.c | 84 ++++++
drivers/hid/ipts/thread.h | 59 ++++
28 files changed, 2850 insertions(+)
create mode 100644 drivers/hid/ipts/Kconfig
create mode 100644 drivers/hid/ipts/Makefile
create mode 100644 drivers/hid/ipts/cmd.c
create mode 100644 drivers/hid/ipts/cmd.h
create mode 100644 drivers/hid/ipts/context.h
create mode 100644 drivers/hid/ipts/control.c
create mode 100644 drivers/hid/ipts/control.h
create mode 100644 drivers/hid/ipts/desc.h
create mode 100644 drivers/hid/ipts/eds1.c
create mode 100644 drivers/hid/ipts/eds1.h
create mode 100644 drivers/hid/ipts/eds2.c
create mode 100644 drivers/hid/ipts/eds2.h
create mode 100644 drivers/hid/ipts/hid.c
create mode 100644 drivers/hid/ipts/hid.h
create mode 100644 drivers/hid/ipts/main.c
create mode 100644 drivers/hid/ipts/mei.c
create mode 100644 drivers/hid/ipts/mei.h
create mode 100644 drivers/hid/ipts/receiver.c
create mode 100644 drivers/hid/ipts/receiver.h
create mode 100644 drivers/hid/ipts/resources.c
create mode 100644 drivers/hid/ipts/resources.h
create mode 100644 drivers/hid/ipts/spec-data.h
create mode 100644 drivers/hid/ipts/spec-device.h
create mode 100644 drivers/hid/ipts/spec-hid.h
create mode 100644 drivers/hid/ipts/thread.c
create mode 100644 drivers/hid/ipts/thread.h
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index e11c1c803676..54f45bdf663e 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -1334,4 +1334,6 @@ source "drivers/hid/amd-sfh-hid/Kconfig"
source "drivers/hid/surface-hid/Kconfig"
+source "drivers/hid/ipts/Kconfig"
+
endif # HID_SUPPORT
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 7a9e160158f7..f58610f27216 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -168,3 +168,5 @@ obj-$(INTEL_ISH_FIRMWARE_DOWNLOADER) += intel-ish-hid/
obj-$(CONFIG_AMD_SFH_HID) += amd-sfh-hid/
obj-$(CONFIG_SURFACE_HID_CORE) += surface-hid/
+
+obj-$(CONFIG_HID_IPTS) += ipts/
diff --git a/drivers/hid/ipts/Kconfig b/drivers/hid/ipts/Kconfig
new file mode 100644
index 000000000000..297401bd388d
--- /dev/null
+++ b/drivers/hid/ipts/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+config HID_IPTS
+ tristate "Intel Precise Touch & Stylus"
+ depends on INTEL_MEI
+ depends on HID
+ help
+ Say Y here if your system has a touchscreen using Intels
+ Precise Touch & Stylus (IPTS) technology.
+
+ If unsure say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ipts.
diff --git a/drivers/hid/ipts/Makefile b/drivers/hid/ipts/Makefile
new file mode 100644
index 000000000000..883896f68e6a
--- /dev/null
+++ b/drivers/hid/ipts/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Makefile for the IPTS touchscreen driver
+#
+
+obj-$(CONFIG_HID_IPTS) += ipts.o
+ipts-objs := cmd.o
+ipts-objs += control.o
+ipts-objs += eds1.o
+ipts-objs += eds2.o
+ipts-objs += hid.o
+ipts-objs += main.o
+ipts-objs += mei.o
+ipts-objs += receiver.o
+ipts-objs += resources.o
+ipts-objs += thread.o
diff --git a/drivers/hid/ipts/cmd.c b/drivers/hid/ipts/cmd.c
new file mode 100644
index 000000000000..63a4934bbc5f
--- /dev/null
+++ b/drivers/hid/ipts/cmd.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+
+#include "cmd.h"
+#include "context.h"
+#include "mei.h"
+#include "spec-device.h"
+
+int ipts_cmd_recv_timeout(struct ipts_context *ipts, enum ipts_command_code code,
+ struct ipts_response *rsp, u64 timeout)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!rsp)
+ return -EFAULT;
+
+ /*
+ * In a response, the command code will have the most significant bit flipped to 1.
+ * If code is passed to ipts_mei_recv as is, no messages will be received.
+ */
+ ret = ipts_mei_recv(&ipts->mei, code | IPTS_RSP_BIT, rsp, timeout);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(ipts->dev, "Received 0x%02X with status 0x%02X\n", code, rsp->status);
+
+ /*
+ * Some devices will always return this error.
+ * It is allowed to ignore it and to try continuing.
+ */
+ if (rsp->status == IPTS_STATUS_COMPAT_CHECK_FAIL)
+ rsp->status = IPTS_STATUS_SUCCESS;
+
+ return 0;
+}
+
+int ipts_cmd_send(struct ipts_context *ipts, enum ipts_command_code code, void *data, size_t size)
+{
+ struct ipts_command cmd = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ cmd.cmd = code;
+
+ if (data && size > 0)
+ memcpy(cmd.payload, data, size);
+
+ dev_dbg(ipts->dev, "Sending 0x%02X with %ld bytes payload\n", code, size);
+ return ipts_mei_send(&ipts->mei, &cmd, sizeof(cmd.cmd) + size);
+}
diff --git a/drivers/hid/ipts/cmd.h b/drivers/hid/ipts/cmd.h
new file mode 100644
index 000000000000..2b4079075b64
--- /dev/null
+++ b/drivers/hid/ipts/cmd.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_CMD_H
+#define IPTS_CMD_H
+
+#include <linux/types.h>
+
+#include "context.h"
+#include "spec-device.h"
+
+/*
+ * The default timeout for receiving responses
+ */
+#define IPTS_CMD_DEFAULT_TIMEOUT 1000
+
+/**
+ * ipts_cmd_recv_timeout() - Receives a response to a command.
+ * @ipts: The IPTS driver context.
+ * @code: The type of the command / response.
+ * @rsp: The address that the received response will be copied to.
+ * @timeout: How many milliseconds the function will wait at most.
+ *
+ * A negative timeout means to wait forever.
+ *
+ * Returns: 0 on success, <0 on error, -EAGAIN if no response has been received.
+ */
+int ipts_cmd_recv_timeout(struct ipts_context *ipts, enum ipts_command_code code,
+ struct ipts_response *rsp, u64 timeout);
+
+/**
+ * ipts_cmd_recv() - Receives a response to a command.
+ * @ipts: The IPTS driver context.
+ * @code: The type of the command / response.
+ * @rsp: The address that the received response will be copied to.
+ *
+ * Returns: 0 on success, <0 on error, -EAGAIN if no response has been received.
+ */
+static inline int ipts_cmd_recv(struct ipts_context *ipts, enum ipts_command_code code,
+ struct ipts_response *rsp)
+{
+ return ipts_cmd_recv_timeout(ipts, code, rsp, IPTS_CMD_DEFAULT_TIMEOUT);
+}
+
+/**
+ * ipts_cmd_send() - Executes a command on the device.
+ * @ipts: The IPTS driver context.
+ * @code: The type of the command to execute.
+ * @data: The payload containing parameters for the command.
+ * @size: The size of the payload.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_cmd_send(struct ipts_context *ipts, enum ipts_command_code code, void *data, size_t size);
+
+#endif /* IPTS_CMD_H */
diff --git a/drivers/hid/ipts/context.h b/drivers/hid/ipts/context.h
new file mode 100644
index 000000000000..ba33259f1f7c
--- /dev/null
+++ b/drivers/hid/ipts/context.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_CONTEXT_H
+#define IPTS_CONTEXT_H
+
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+
+#include "mei.h"
+#include "resources.h"
+#include "spec-device.h"
+#include "thread.h"
+
+struct ipts_context {
+ struct device *dev;
+ struct ipts_mei mei;
+
+ enum ipts_mode mode;
+
+ /*
+ * Prevents concurrent GET_FEATURE reports.
+ */
+ struct mutex feature_lock;
+ struct completion feature_event;
+
+ /*
+ * These are not inside of struct ipts_resources
+ * because they don't own the memory they point to.
+ */
+ struct ipts_buffer feature_report;
+ struct ipts_buffer descriptor;
+
+ bool hid_active;
+ struct hid_device *hid;
+
+ struct ipts_device_info info;
+ struct ipts_resources resources;
+
+ struct ipts_thread receiver_loop;
+};
+
+#endif /* IPTS_CONTEXT_H */
diff --git a/drivers/hid/ipts/control.c b/drivers/hid/ipts/control.c
new file mode 100644
index 000000000000..5360842d260b
--- /dev/null
+++ b/drivers/hid/ipts/control.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/delay.h>
+#include <linux/dev_printk.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/types.h>
+
+#include "cmd.h"
+#include "context.h"
+#include "control.h"
+#include "desc.h"
+#include "hid.h"
+#include "receiver.h"
+#include "resources.h"
+#include "spec-data.h"
+#include "spec-device.h"
+
+static int ipts_control_get_device_info(struct ipts_context *ipts, struct ipts_device_info *info)
+{
+ int ret = 0;
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!info)
+ return -EFAULT;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_GET_DEVICE_INFO, NULL, 0);
+ if (ret) {
+ dev_err(ipts->dev, "GET_DEVICE_INFO: send failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_GET_DEVICE_INFO, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "GET_DEVICE_INFO: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "GET_DEVICE_INFO: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ memcpy(info, rsp.payload, sizeof(*info));
+ return 0;
+}
+
+static int ipts_control_set_mode(struct ipts_context *ipts, enum ipts_mode mode)
+{
+ int ret = 0;
+ struct ipts_set_mode cmd = { 0 };
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ cmd.mode = mode;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_SET_MODE, &cmd, sizeof(cmd));
+ if (ret) {
+ dev_err(ipts->dev, "SET_MODE: send failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_SET_MODE, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "SET_MODE: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "SET_MODE: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ return 0;
+}
+
+static int ipts_control_set_mem_window(struct ipts_context *ipts, struct ipts_resources *res)
+{
+ int i = 0;
+ int ret = 0;
+ struct ipts_mem_window cmd = { 0 };
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!res)
+ return -EFAULT;
+
+ for (i = 0; i < IPTS_BUFFERS; i++) {
+ cmd.data_addr_lower[i] = lower_32_bits(res->data[i].dma_address);
+ cmd.data_addr_upper[i] = upper_32_bits(res->data[i].dma_address);
+ cmd.feedback_addr_lower[i] = lower_32_bits(res->feedback[i].dma_address);
+ cmd.feedback_addr_upper[i] = upper_32_bits(res->feedback[i].dma_address);
+ }
+
+ cmd.workqueue_addr_lower = lower_32_bits(res->workqueue.dma_address);
+ cmd.workqueue_addr_upper = upper_32_bits(res->workqueue.dma_address);
+
+ cmd.doorbell_addr_lower = lower_32_bits(res->doorbell.dma_address);
+ cmd.doorbell_addr_upper = upper_32_bits(res->doorbell.dma_address);
+
+ cmd.hid2me_addr_lower = lower_32_bits(res->hid2me.dma_address);
+ cmd.hid2me_addr_upper = upper_32_bits(res->hid2me.dma_address);
+
+ cmd.workqueue_size = IPTS_WORKQUEUE_SIZE;
+ cmd.workqueue_item_size = IPTS_WORKQUEUE_ITEM_SIZE;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_SET_MEM_WINDOW, &cmd, sizeof(cmd));
+ if (ret) {
+ dev_err(ipts->dev, "SET_MEM_WINDOW: send failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_SET_MEM_WINDOW, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "SET_MEM_WINDOW: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "SET_MEM_WINDOW: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ return 0;
+}
+
+static int ipts_control_get_descriptor(struct ipts_context *ipts)
+{
+ int ret = 0;
+ struct ipts_data_header *header = NULL;
+ struct ipts_get_descriptor cmd = { 0 };
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!ipts->resources.descriptor.address)
+ return -EFAULT;
+
+ memset(ipts->resources.descriptor.address, 0, ipts->resources.descriptor.size);
+
+ cmd.addr_lower = lower_32_bits(ipts->resources.descriptor.dma_address);
+ cmd.addr_upper = upper_32_bits(ipts->resources.descriptor.dma_address);
+ cmd.magic = 8;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_GET_DESCRIPTOR, &cmd, sizeof(cmd));
+ if (ret) {
+ dev_err(ipts->dev, "GET_DESCRIPTOR: send failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_GET_DESCRIPTOR, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "GET_DESCRIPTOR: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "GET_DESCRIPTOR: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ header = (struct ipts_data_header *)ipts->resources.descriptor.address;
+
+ if (header->type == IPTS_DATA_TYPE_DESCRIPTOR) {
+ ipts->descriptor.address = &header->data[8];
+ ipts->descriptor.size = header->size - 8;
+
+ return 0;
+ }
+
+ return -ENODATA;
+}
+
+int ipts_control_request_flush(struct ipts_context *ipts)
+{
+ int ret = 0;
+ struct ipts_quiesce_io cmd = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_QUIESCE_IO, &cmd, sizeof(cmd));
+ if (ret)
+ dev_err(ipts->dev, "QUIESCE_IO: send failed: %d\n", ret);
+
+ return ret;
+}
+
+int ipts_control_wait_flush(struct ipts_context *ipts)
+{
+ int ret = 0;
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_QUIESCE_IO, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "QUIESCE_IO: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ if (rsp.status == IPTS_STATUS_TIMEOUT)
+ return -EAGAIN;
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "QUIESCE_IO: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ return 0;
+}
+
+int ipts_control_request_data(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_READY_FOR_DATA, NULL, 0);
+ if (ret)
+ dev_err(ipts->dev, "READY_FOR_DATA: send failed: %d\n", ret);
+
+ return ret;
+}
+
+int ipts_control_wait_data(struct ipts_context *ipts, bool shutdown)
+{
+ int ret = 0;
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!shutdown)
+ ret = ipts_cmd_recv_timeout(ipts, IPTS_CMD_READY_FOR_DATA, &rsp, 0);
+ else
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_READY_FOR_DATA, &rsp);
+
+ if (ret) {
+ if (ret != -EAGAIN)
+ dev_err(ipts->dev, "READY_FOR_DATA: recv failed: %d\n", ret);
+
+ return ret;
+ }
+
+ /*
+ * During shutdown, it is possible that the sensor has already been disabled.
+ */
+ if (rsp.status == IPTS_STATUS_SENSOR_DISABLED)
+ return 0;
+
+ if (rsp.status == IPTS_STATUS_TIMEOUT)
+ return -EAGAIN;
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "READY_FOR_DATA: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ return 0;
+}
+
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer)
+{
+ int ret = 0;
+ struct ipts_feedback cmd = { 0 };
+ struct ipts_response rsp = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ cmd.buffer = buffer;
+
+ ret = ipts_cmd_send(ipts, IPTS_CMD_FEEDBACK, &cmd, sizeof(cmd));
+ if (ret) {
+ dev_err(ipts->dev, "FEEDBACK: send failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_cmd_recv(ipts, IPTS_CMD_FEEDBACK, &rsp);
+ if (ret) {
+ dev_err(ipts->dev, "FEEDBACK: recv failed: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * We don't know what feedback data looks like so we are sending zeros.
+ * See also ipts_control_refill_buffer.
+ */
+ if (rsp.status == IPTS_STATUS_INVALID_PARAMS)
+ return 0;
+
+ if (rsp.status != IPTS_STATUS_SUCCESS) {
+ dev_err(ipts->dev, "FEEDBACK: cmd failed: %d\n", rsp.status);
+ return -EBADR;
+ }
+
+ return 0;
+}
+
+int ipts_control_hid2me_feedback(struct ipts_context *ipts, enum ipts_feedback_cmd_type cmd,
+ enum ipts_feedback_data_type type, void *data, size_t size)
+{
+ struct ipts_feedback_header *header = NULL;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!ipts->resources.hid2me.address)
+ return -EFAULT;
+
+ memset(ipts->resources.hid2me.address, 0, ipts->resources.hid2me.size);
+ header = (struct ipts_feedback_header *)ipts->resources.hid2me.address;
+
+ header->cmd_type = cmd;
+ header->data_type = type;
+ header->size = size;
+ header->buffer = IPTS_HID2ME_BUFFER;
+
+ if (size + sizeof(*header) > ipts->resources.hid2me.size)
+ return -EINVAL;
+
+ if (data && size > 0)
+ memcpy(header->payload, data, size);
+
+ return ipts_control_send_feedback(ipts, IPTS_HID2ME_BUFFER);
+}
+
+int ipts_control_start(struct ipts_context *ipts)
+{
+ int ret = 0;
+ struct ipts_device_info info = { 0 };
+
+ if (!ipts)
+ return -EFAULT;
+
+ dev_info(ipts->dev, "Starting IPTS\n");
+
+ ret = ipts_control_get_device_info(ipts, &info);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to get device info: %d\n", ret);
+ return ret;
+ }
+
+ ipts->info = info;
+
+ ret = ipts_resources_init(&ipts->resources, ipts->dev, info.data_size, info.feedback_size);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to allocate buffers: %d", ret);
+ return ret;
+ }
+
+ dev_info(ipts->dev, "IPTS EDS Version: %d\n", info.intf_eds);
+
+ /*
+ * Handle newer devices
+ */
+ if (info.intf_eds > 1) {
+ /*
+ * Fetching the descriptor will only work on newer devices.
+ * For older devices, a fallback descriptor will be used.
+ */
+ ret = ipts_control_get_descriptor(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to fetch HID descriptor: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * Newer devices can be directly initialized in polling mode.
+ */
+ ipts->mode = IPTS_MODE_POLL;
+ }
+
+ ret = ipts_control_set_mode(ipts, ipts->mode);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to set mode: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_control_set_mem_window(ipts, &ipts->resources);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to set memory window: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_receiver_start(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to start receiver: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_control_request_data(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to request data: %d\n", ret);
+ return ret;
+ }
+
+ ipts_hid_enable(ipts);
+
+ ret = ipts_hid_init(ipts, info);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to initialize HID device: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int _ipts_control_stop(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ ipts_hid_disable(ipts);
+ dev_info(ipts->dev, "Stopping IPTS\n");
+
+ ret = ipts_receiver_stop(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to stop receiver: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_resources_free(&ipts->resources);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to free resources: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+int ipts_control_stop(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ ret = _ipts_control_stop(ipts);
+ if (ret)
+ return ret;
+
+ ret = ipts_hid_free(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to free HID device: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+int ipts_control_restart(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ ret = _ipts_control_stop(ipts);
+ if (ret)
+ return ret;
+
+ /*
+ * Wait a second to give the sensor time to fully shut down.
+ */
+ msleep(1000);
+
+ ret = ipts_control_start(ipts);
+ if (ret)
+ return ret;
+
+ return 0;
+}
diff --git a/drivers/hid/ipts/control.h b/drivers/hid/ipts/control.h
new file mode 100644
index 000000000000..26629c5144ed
--- /dev/null
+++ b/drivers/hid/ipts/control.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_CONTROL_H
+#define IPTS_CONTROL_H
+
+#include <linux/types.h>
+
+#include "context.h"
+#include "spec-data.h"
+#include "spec-device.h"
+
+/**
+ * ipts_control_request_flush() - Stop the data flow.
+ * @ipts: The IPTS driver context.
+ *
+ * Runs the command to stop the data flow on the device.
+ * All outstanding data needs to be acknowledged using feedback before the command will return.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_request_flush(struct ipts_context *ipts);
+
+/**
+ * ipts_control_wait_flush() - Wait until data flow has been stopped.
+ * @ipts: The IPTS driver context.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_wait_flush(struct ipts_context *ipts);
+
+/**
+ * ipts_control_wait_flush() - Notify the device that the driver can receive new data.
+ * @ipts: The IPTS driver context.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_request_data(struct ipts_context *ipts);
+
+/**
+ * ipts_control_wait_data() - Wait until new data is available.
+ * @ipts: The IPTS driver context.
+ * @block: Whether to block execution until data is available.
+ *
+ * In poll mode, this function will never return while the data flow is active. Instead,
+ * the poll will be incremented when new data is available.
+ *
+ * Returns: 0 on success, <0 on error, -EAGAIN if no data is available.
+ */
+int ipts_control_wait_data(struct ipts_context *ipts, bool block);
+
+/**
+ * ipts_control_send_feedback() - Submits a feedback buffer to the device.
+ * @ipts: The IPTS driver context.
+ * @buffer: The ID of the buffer containing feedback data.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_send_feedback(struct ipts_context *ipts, u32 buffer);
+
+/**
+ * ipts_control_hid2me_feedback() - Sends HID2ME feedback, a special type of feedback.
+ * @ipts: The IPTS driver context.
+ * @cmd: The command that will be run on the device.
+ * @type: The type of the payload that is sent to the device.
+ * @data: The payload of the feedback command.
+ * @size: The size of the payload.
+ *
+ * HID2ME feedback is a special type of feedback, because it allows interfacing with
+ * the HID API of the device at any moment, without requiring a buffer that has to
+ * be acknowledged.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_hid2me_feedback(struct ipts_context *ipts, enum ipts_feedback_cmd_type cmd,
+ enum ipts_feedback_data_type type, void *data, size_t size);
+
+/**
+ * ipts_control_refill_buffer() - Acknowledges that data in a buffer has been processed.
+ * @ipts: The IPTS driver context.
+ * @buffer: The buffer that has been processed and can be refilled.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+static inline int ipts_control_refill_buffer(struct ipts_context *ipts, u32 buffer)
+{
+ /*
+ * IPTS expects structured data in the feedback buffer matching the buffer that will be
+ * refilled. We don't know what that data looks like, so we just keep the buffer empty.
+ * This results in an INVALID_PARAMS error, but the buffer gets refilled without an issue.
+ * Sending a minimal structure with the buffer ID fixes the error, but breaks refilling
+ * the buffers on some devices.
+ */
+
+ return ipts_control_send_feedback(ipts, buffer);
+}
+
+/**
+ * ipts_control_start() - Initialized the device and starts the data flow.
+ * @ipts: The IPTS driver context.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_start(struct ipts_context *ipts);
+
+/**
+ * ipts_control_stop() - Stops the data flow and resets the device.
+ * @ipts: The IPTS driver context.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_stop(struct ipts_context *ipts);
+
+/**
+ * ipts_control_restart() - Stops the device and starts it again.
+ * @ipts: The IPTS driver context.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_control_restart(struct ipts_context *ipts);
+
+#endif /* IPTS_CONTROL_H */
diff --git a/drivers/hid/ipts/desc.h b/drivers/hid/ipts/desc.h
new file mode 100644
index 000000000000..307438c7c80c
--- /dev/null
+++ b/drivers/hid/ipts/desc.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2022-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_DESC_H
+#define IPTS_DESC_H
+
+#include <linux/types.h>
+
+#define IPTS_HID_REPORT_SINGLETOUCH 64
+#define IPTS_HID_REPORT_DATA 65
+#define IPTS_HID_REPORT_SET_MODE 66
+
+#define IPTS_HID_REPORT_DATA_SIZE 7485
+
+/*
+ * HID descriptor for singletouch data.
+ * This descriptor should be present on all IPTS devices.
+ */
+static const u8 ipts_singletouch_descriptor[] = {
+ 0x05, 0x0D, /* Usage Page (Digitizer), */
+ 0x09, 0x04, /* Usage (Touchscreen), */
+ 0xA1, 0x01, /* Collection (Application), */
+ 0x85, 0x40, /* Report ID (64), */
+ 0x09, 0x42, /* Usage (Tip Switch), */
+ 0x15, 0x00, /* Logical Minimum (0), */
+ 0x25, 0x01, /* Logical Maximum (1), */
+ 0x75, 0x01, /* Report Size (1), */
+ 0x95, 0x01, /* Report Count (1), */
+ 0x81, 0x02, /* Input (Variable), */
+ 0x95, 0x07, /* Report Count (7), */
+ 0x81, 0x03, /* Input (Constant, Variable), */
+ 0x05, 0x01, /* Usage Page (Desktop), */
+ 0x09, 0x30, /* Usage (X), */
+ 0x75, 0x10, /* Report Size (16), */
+ 0x95, 0x01, /* Report Count (1), */
+ 0xA4, /* Push, */
+ 0x55, 0x0E, /* Unit Exponent (14), */
+ 0x65, 0x11, /* Unit (Centimeter), */
+ 0x46, 0x76, 0x0B, /* Physical Maximum (2934), */
+ 0x26, 0xFF, 0x7F, /* Logical Maximum (32767), */
+ 0x81, 0x02, /* Input (Variable), */
+ 0x09, 0x31, /* Usage (Y), */
+ 0x46, 0x74, 0x06, /* Physical Maximum (1652), */
+ 0x26, 0xFF, 0x7F, /* Logical Maximum (32767), */
+ 0x81, 0x02, /* Input (Variable), */
+ 0xB4, /* Pop, */
+ 0xC0, /* End Collection */
+};
+
+/*
+ * Fallback HID descriptor for older devices that do not have
+ * the ability to query their HID descriptor.
+ */
+static const u8 ipts_fallback_descriptor[] = {
+ 0x05, 0x0D, /* Usage Page (Digitizer), */
+ 0x09, 0x0F, /* Usage (Capacitive Hm Digitizer), */
+ 0xA1, 0x01, /* Collection (Application), */
+ 0x85, 0x41, /* Report ID (65), */
+ 0x09, 0x56, /* Usage (Scan Time), */
+ 0x95, 0x01, /* Report Count (1), */
+ 0x75, 0x10, /* Report Size (16), */
+ 0x81, 0x02, /* Input (Variable), */
+ 0x09, 0x61, /* Usage (Gesture Char Quality), */
+ 0x75, 0x08, /* Report Size (8), */
+ 0x96, 0x3D, 0x1D, /* Report Count (7485), */
+ 0x81, 0x03, /* Input (Constant, Variable), */
+ 0x85, 0x42, /* Report ID (66), */
+ 0x06, 0x00, 0xFF, /* Usage Page (FF00h), */
+ 0x09, 0xC8, /* Usage (C8h), */
+ 0x75, 0x08, /* Report Size (8), */
+ 0x95, 0x01, /* Report Count (1), */
+ 0xB1, 0x02, /* Feature (Variable), */
+ 0xC0, /* End Collection, */
+};
+
+#endif /* IPTS_DESC_H */
diff --git a/drivers/hid/ipts/eds1.c b/drivers/hid/ipts/eds1.c
new file mode 100644
index 000000000000..ecbb3a8bdaf6
--- /dev/null
+++ b/drivers/hid/ipts/eds1.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/hid.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "control.h"
+#include "desc.h"
+#include "spec-device.h"
+
+int ipts_eds1_get_descriptor(struct ipts_context *ipts, u8 **desc_buffer, size_t *desc_size)
+{
+ size_t size = 0;
+ u8 *buffer = NULL;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!desc_buffer)
+ return -EFAULT;
+
+ if (!desc_size)
+ return -EFAULT;
+
+ size = sizeof(ipts_singletouch_descriptor) + sizeof(ipts_fallback_descriptor);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ memcpy(buffer, ipts_singletouch_descriptor, sizeof(ipts_singletouch_descriptor));
+ memcpy(&buffer[sizeof(ipts_singletouch_descriptor)], ipts_fallback_descriptor,
+ sizeof(ipts_fallback_descriptor));
+
+ *desc_size = size;
+ *desc_buffer = buffer;
+
+ return 0;
+}
+
+static int ipts_eds1_switch_mode(struct ipts_context *ipts, enum ipts_mode mode)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (ipts->mode == mode)
+ return 0;
+
+ ipts->mode = mode;
+
+ ret = ipts_control_restart(ipts);
+ if (ret)
+ dev_err(ipts->dev, "Failed to switch modes: %d\n", ret);
+
+ return ret;
+}
+
+int ipts_eds1_raw_request(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum hid_report_type report_type, enum hid_class_request request_type)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!buffer)
+ return -EFAULT;
+
+ if (report_id != IPTS_HID_REPORT_SET_MODE)
+ return -EIO;
+
+ if (report_type != HID_FEATURE_REPORT)
+ return -EIO;
+
+ if (size != 2)
+ return -EINVAL;
+
+ /*
+ * Implement mode switching report for older devices without native HID support.
+ */
+
+ if (request_type == HID_REQ_GET_REPORT) {
+ memset(buffer, 0, size);
+ buffer[0] = report_id;
+ buffer[1] = ipts->mode;
+ } else if (request_type == HID_REQ_SET_REPORT) {
+ return ipts_eds1_switch_mode(ipts, buffer[1]);
+ } else {
+ return -EIO;
+ }
+
+ return ret;
+}
diff --git a/drivers/hid/ipts/eds1.h b/drivers/hid/ipts/eds1.h
new file mode 100644
index 000000000000..eeeb6575e3e8
--- /dev/null
+++ b/drivers/hid/ipts/eds1.h
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/hid.h>
+#include <linux/types.h>
+
+#include "context.h"
+
+/**
+ * ipts_eds1_get_descriptor() - Assembles the HID descriptor of the device.
+ * @ipts: The IPTS driver context.
+ * @desc_buffer: A pointer to the location where the address of the allocated buffer is stored.
+ * @desc_size: A pointer to the location where the size of the allocated buffer is stored.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_eds1_get_descriptor(struct ipts_context *ipts, u8 **desc_buffer, size_t *desc_size);
+
+/**
+ * ipts_eds1_raw_request() - Executes an output or feature report on the device.
+ * @ipts: The IPTS driver context.
+ * @buffer: The buffer containing the report.
+ * @size: The size of the buffer.
+ * @report_id: The HID report ID.
+ * @report_type: Whether this report is an output or a feature report.
+ * @request_type: Whether this report requests or sends data.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_eds1_raw_request(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum hid_report_type report_type, enum hid_class_request request_type);
diff --git a/drivers/hid/ipts/eds2.c b/drivers/hid/ipts/eds2.c
new file mode 100644
index 000000000000..198dc65d7887
--- /dev/null
+++ b/drivers/hid/ipts/eds2.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "control.h"
+#include "desc.h"
+#include "spec-data.h"
+
+int ipts_eds2_get_descriptor(struct ipts_context *ipts, u8 **desc_buffer, size_t *desc_size)
+{
+ size_t size = 0;
+ u8 *buffer = NULL;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!desc_buffer)
+ return -EFAULT;
+
+ if (!desc_size)
+ return -EFAULT;
+
+ size = sizeof(ipts_singletouch_descriptor) + ipts->descriptor.size;
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ memcpy(buffer, ipts_singletouch_descriptor, sizeof(ipts_singletouch_descriptor));
+ memcpy(&buffer[sizeof(ipts_singletouch_descriptor)], ipts->descriptor.address,
+ ipts->descriptor.size);
+
+ *desc_size = size;
+ *desc_buffer = buffer;
+
+ return 0;
+}
+
+static int ipts_eds2_get_feature(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum ipts_feedback_data_type type)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!buffer)
+ return -EFAULT;
+
+ mutex_lock(&ipts->feature_lock);
+
+ memset(buffer, 0, size);
+ buffer[0] = report_id;
+
+ memset(&ipts->feature_report, 0, sizeof(ipts->feature_report));
+ reinit_completion(&ipts->feature_event);
+
+ ret = ipts_control_hid2me_feedback(ipts, IPTS_FEEDBACK_CMD_TYPE_NONE, type, buffer, size);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to send hid2me feedback: %d\n", ret);
+ goto out;
+ }
+
+ ret = wait_for_completion_timeout(&ipts->feature_event, msecs_to_jiffies(5000));
+ if (ret == 0) {
+ dev_warn(ipts->dev, "GET_FEATURES timed out!\n");
+ ret = -EIO;
+ goto out;
+ }
+
+ if (!ipts->feature_report.address) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ if (ipts->feature_report.size > size) {
+ ret = -ETOOSMALL;
+ goto out;
+ }
+
+ ret = ipts->feature_report.size;
+ memcpy(buffer, ipts->feature_report.address, ipts->feature_report.size);
+
+out:
+ mutex_unlock(&ipts->feature_lock);
+ return ret;
+}
+
+static int ipts_eds2_set_feature(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum ipts_feedback_data_type type)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!buffer)
+ return -EFAULT;
+
+ buffer[0] = report_id;
+
+ ret = ipts_control_hid2me_feedback(ipts, IPTS_FEEDBACK_CMD_TYPE_NONE, type, buffer, size);
+ if (ret)
+ dev_err(ipts->dev, "Failed to send hid2me feedback: %d\n", ret);
+
+ return ret;
+}
+
+int ipts_eds2_raw_request(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum hid_report_type report_type, enum hid_class_request request_type)
+{
+ enum ipts_feedback_data_type feedback_type = IPTS_FEEDBACK_DATA_TYPE_VENDOR;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!buffer)
+ return -EFAULT;
+
+ if (report_type == HID_OUTPUT_REPORT && request_type == HID_REQ_SET_REPORT)
+ feedback_type = IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT;
+ else if (report_type == HID_FEATURE_REPORT && request_type == HID_REQ_GET_REPORT)
+ feedback_type = IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES;
+ else if (report_type == HID_FEATURE_REPORT && request_type == HID_REQ_SET_REPORT)
+ feedback_type = IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES;
+ else
+ return -EIO;
+
+ if (request_type == HID_REQ_GET_REPORT)
+ return ipts_eds2_get_feature(ipts, buffer, size, report_id, feedback_type);
+ else
+ return ipts_eds2_set_feature(ipts, buffer, size, report_id, feedback_type);
+}
diff --git a/drivers/hid/ipts/eds2.h b/drivers/hid/ipts/eds2.h
new file mode 100644
index 000000000000..064e3716907a
--- /dev/null
+++ b/drivers/hid/ipts/eds2.h
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/hid.h>
+#include <linux/types.h>
+
+#include "context.h"
+
+/**
+ * ipts_eds2_get_descriptor() - Assembles the HID descriptor of the device.
+ * @ipts: The IPTS driver context.
+ * @desc_buffer: A pointer to the location where the address of the allocated buffer is stored.
+ * @desc_size: A pointer to the location where the size of the allocated buffer is stored.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_eds2_get_descriptor(struct ipts_context *ipts, u8 **desc_buffer, size_t *desc_size);
+
+/**
+ * ipts_eds2_raw_request() - Executes an output or feature report on the device.
+ * @ipts: The IPTS driver context.
+ * @buffer: The buffer containing the report.
+ * @size: The size of the buffer.
+ * @report_id: The HID report ID.
+ * @report_type: Whether this report is an output or a feature report.
+ * @request_type: Whether this report requests or sends data.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_eds2_raw_request(struct ipts_context *ipts, u8 *buffer, size_t size, u8 report_id,
+ enum hid_report_type report_type, enum hid_class_request request_type);
diff --git a/drivers/hid/ipts/hid.c b/drivers/hid/ipts/hid.c
new file mode 100644
index 000000000000..e34a1a4f9fa7
--- /dev/null
+++ b/drivers/hid/ipts/hid.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/hid.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "desc.h"
+#include "eds1.h"
+#include "eds2.h"
+#include "hid.h"
+#include "spec-data.h"
+#include "spec-hid.h"
+
+void ipts_hid_enable(struct ipts_context *ipts)
+{
+ WRITE_ONCE(ipts->hid_active, true);
+}
+
+void ipts_hid_disable(struct ipts_context *ipts)
+{
+ WRITE_ONCE(ipts->hid_active, false);
+}
+
+static int ipts_hid_start(struct hid_device *hid)
+{
+ return 0;
+}
+
+static void ipts_hid_stop(struct hid_device *hid)
+{
+}
+
+static int ipts_hid_parse(struct hid_device *hid)
+{
+ int ret = 0;
+ struct ipts_context *ipts = NULL;
+
+ u8 *buffer = NULL;
+ size_t size = 0;
+
+ if (!hid)
+ return -ENODEV;
+
+ ipts = hid->driver_data;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!READ_ONCE(ipts->hid_active))
+ return -ENODEV;
+
+ if (ipts->info.intf_eds == 1)
+ ret = ipts_eds1_get_descriptor(ipts, &buffer, &size);
+ else
+ ret = ipts_eds2_get_descriptor(ipts, &buffer, &size);
+
+ if (ret) {
+ dev_err(ipts->dev, "Failed to allocate HID descriptor: %d\n", ret);
+ return ret;
+ }
+
+ ret = hid_parse_report(hid, buffer, size);
+ kfree(buffer);
+
+ if (ret) {
+ dev_err(ipts->dev, "Failed to parse HID descriptor: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int ipts_hid_raw_request(struct hid_device *hid, unsigned char report_id, __u8 *buffer,
+ size_t size, unsigned char report_type, int request_type)
+{
+ struct ipts_context *ipts = NULL;
+
+ if (!hid)
+ return -ENODEV;
+
+ ipts = hid->driver_data;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!READ_ONCE(ipts->hid_active))
+ return -ENODEV;
+
+ if (ipts->info.intf_eds == 1) {
+ return ipts_eds1_raw_request(ipts, buffer, size, report_id, report_type,
+ request_type);
+ } else {
+ return ipts_eds2_raw_request(ipts, buffer, size, report_id, report_type,
+ request_type);
+ }
+}
+
+static struct hid_ll_driver ipts_hid_driver = {
+ .start = ipts_hid_start,
+ .stop = ipts_hid_stop,
+ .open = ipts_hid_start,
+ .close = ipts_hid_stop,
+ .parse = ipts_hid_parse,
+ .raw_request = ipts_hid_raw_request,
+};
+
+int ipts_hid_input_data(struct ipts_context *ipts, u32 buffer)
+{
+ u8 *temp = NULL;
+ struct ipts_hid_header *frame = NULL;
+ struct ipts_data_header *header = NULL;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (!ipts->hid)
+ return -ENODEV;
+
+ if (!READ_ONCE(ipts->hid_active))
+ return -ENODEV;
+
+ header = (struct ipts_data_header *)ipts->resources.data[buffer].address;
+
+ temp = ipts->resources.report.address;
+ memset(temp, 0, ipts->resources.report.size);
+
+ if (!header)
+ return -EFAULT;
+
+ if (header->size == 0)
+ return 0;
+
+ if (header->type == IPTS_DATA_TYPE_HID)
+ return hid_input_report(ipts->hid, HID_INPUT_REPORT, header->data, header->size, 1);
+
+ if (header->type == IPTS_DATA_TYPE_GET_FEATURES) {
+ ipts->feature_report.address = header->data;
+ ipts->feature_report.size = header->size;
+
+ complete_all(&ipts->feature_event);
+ return 0;
+ }
+
+ if (header->type != IPTS_DATA_TYPE_FRAME)
+ return 0;
+
+ if (header->size + 3 + sizeof(struct ipts_hid_header) > IPTS_HID_REPORT_DATA_SIZE)
+ return -ERANGE;
+
+ /*
+ * Synthesize a HID report matching the devices that natively send HID reports
+ */
+ temp[0] = IPTS_HID_REPORT_DATA;
+
+ frame = (struct ipts_hid_header *)&temp[3];
+ frame->type = IPTS_HID_FRAME_TYPE_RAW;
+ frame->size = header->size + sizeof(*frame);
+
+ memcpy(frame->data, header->data, header->size);
+
+ return hid_input_report(ipts->hid, HID_INPUT_REPORT, temp, IPTS_HID_REPORT_DATA_SIZE, 1);
+}
+
+int ipts_hid_init(struct ipts_context *ipts, struct ipts_device_info info)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (ipts->hid)
+ return 0;
+
+ ipts->hid = hid_allocate_device();
+ if (IS_ERR(ipts->hid)) {
+ int err = PTR_ERR(ipts->hid);
+
+ dev_err(ipts->dev, "Failed to allocate HID device: %d\n", err);
+ return err;
+ }
+
+ ipts->hid->driver_data = ipts;
+ ipts->hid->dev.parent = ipts->dev;
+ ipts->hid->ll_driver = &ipts_hid_driver;
+
+ ipts->hid->vendor = info.vendor;
+ ipts->hid->product = info.product;
+ ipts->hid->group = HID_GROUP_GENERIC;
+
+ snprintf(ipts->hid->name, sizeof(ipts->hid->name), "IPTS %04X:%04X", info.vendor,
+ info.product);
+
+ ret = hid_add_device(ipts->hid);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to add HID device: %d\n", ret);
+ ipts_hid_free(ipts);
+ return ret;
+ }
+
+ return 0;
+}
+
+int ipts_hid_free(struct ipts_context *ipts)
+{
+ if (!ipts)
+ return -EFAULT;
+
+ if (!ipts->hid)
+ return 0;
+
+ hid_destroy_device(ipts->hid);
+ ipts->hid = NULL;
+
+ return 0;
+}
diff --git a/drivers/hid/ipts/hid.h b/drivers/hid/ipts/hid.h
new file mode 100644
index 000000000000..1ebe77447903
--- /dev/null
+++ b/drivers/hid/ipts/hid.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2022-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_HID_H
+#define IPTS_HID_H
+
+#include <linux/types.h>
+
+#include "context.h"
+#include "spec-device.h"
+
+void ipts_hid_enable(struct ipts_context *ipts);
+void ipts_hid_disable(struct ipts_context *ipts);
+
+int ipts_hid_input_data(struct ipts_context *ipts, u32 buffer);
+
+int ipts_hid_init(struct ipts_context *ipts, struct ipts_device_info info);
+int ipts_hid_free(struct ipts_context *ipts);
+
+#endif /* IPTS_HID_H */
diff --git a/drivers/hid/ipts/main.c b/drivers/hid/ipts/main.c
new file mode 100644
index 000000000000..fb5b5c13ee3e
--- /dev/null
+++ b/drivers/hid/ipts/main.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+#include "context.h"
+#include "control.h"
+#include "mei.h"
+#include "receiver.h"
+#include "spec-device.h"
+
+/*
+ * The MEI client ID for IPTS functionality.
+ */
+#define IPTS_ID UUID_LE(0x3e8d0870, 0x271a, 0x4208, 0x8e, 0xb5, 0x9a, 0xcb, 0x94, 0x02, 0xae, 0x04)
+
+static int ipts_set_dma_mask(struct mei_cl_device *cldev)
+{
+ if (!cldev)
+ return -EFAULT;
+
+ if (!dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(64)))
+ return 0;
+
+ return dma_coerce_mask_and_coherent(&cldev->dev, DMA_BIT_MASK(32));
+}
+
+static int ipts_probe(struct mei_cl_device *cldev, const struct mei_cl_device_id *id)
+{
+ int ret = 0;
+ struct ipts_context *ipts = NULL;
+
+ if (!cldev)
+ return -EFAULT;
+
+ ret = ipts_set_dma_mask(cldev);
+ if (ret) {
+ dev_err(&cldev->dev, "Failed to set DMA mask for IPTS: %d\n", ret);
+ return ret;
+ }
+
+ ret = mei_cldev_enable(cldev);
+ if (ret) {
+ dev_err(&cldev->dev, "Failed to enable MEI device: %d\n", ret);
+ return ret;
+ }
+
+ ipts = devm_kzalloc(&cldev->dev, sizeof(*ipts), GFP_KERNEL);
+ if (!ipts) {
+ mei_cldev_disable(cldev);
+ return -ENOMEM;
+ }
+
+ ret = ipts_mei_init(&ipts->mei, cldev);
+ if (ret) {
+ dev_err(&cldev->dev, "Failed to init MEI bus logic: %d\n", ret);
+ return ret;
+ }
+
+ ipts->dev = &cldev->dev;
+ ipts->mode = IPTS_MODE_EVENT;
+
+ mutex_init(&ipts->feature_lock);
+ init_completion(&ipts->feature_event);
+
+ mei_cldev_set_drvdata(cldev, ipts);
+
+ ret = ipts_control_start(ipts);
+ if (ret) {
+ dev_err(&cldev->dev, "Failed to start IPTS: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void ipts_remove(struct mei_cl_device *cldev)
+{
+ int ret = 0;
+ struct ipts_context *ipts = NULL;
+
+ if (!cldev) {
+ pr_err("MEI device is NULL!");
+ return;
+ }
+
+ ipts = mei_cldev_get_drvdata(cldev);
+
+ ret = ipts_control_stop(ipts);
+ if (ret)
+ dev_err(&cldev->dev, "Failed to stop IPTS: %d\n", ret);
+
+ mei_cldev_disable(cldev);
+}
+
+static struct mei_cl_device_id ipts_device_id_table[] = {
+ { .uuid = IPTS_ID, .version = MEI_CL_VERSION_ANY },
+ {},
+};
+MODULE_DEVICE_TABLE(mei, ipts_device_id_table);
+
+static struct mei_cl_driver ipts_driver = {
+ .id_table = ipts_device_id_table,
+ .name = "ipts",
+ .probe = ipts_probe,
+ .remove = ipts_remove,
+};
+module_mei_cl_driver(ipts_driver);
+
+MODULE_DESCRIPTION("IPTS touchscreen driver");
+MODULE_AUTHOR("Dorian Stoll <dorian.stoll@tmsp.io>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/ipts/mei.c b/drivers/hid/ipts/mei.c
new file mode 100644
index 000000000000..1e0395ceae4a
--- /dev/null
+++ b/drivers/hid/ipts/mei.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/list.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/printk.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "context.h"
+#include "mei.h"
+
+static void locked_list_add(struct list_head *new, struct list_head *head,
+ struct rw_semaphore *lock)
+{
+ down_write(lock);
+ list_add(new, head);
+ up_write(lock);
+}
+
+static void locked_list_del(struct list_head *entry, struct rw_semaphore *lock)
+{
+ down_write(lock);
+ list_del(entry);
+ up_write(lock);
+}
+
+static void ipts_mei_incoming(struct mei_cl_device *cldev)
+{
+ ssize_t ret = 0;
+ struct ipts_mei_message *entry = NULL;
+ struct ipts_context *ipts = NULL;
+
+ if (!cldev) {
+ pr_err("MEI device is NULL!");
+ return;
+ }
+
+ ipts = mei_cldev_get_drvdata(cldev);
+ if (!ipts) {
+ pr_err("IPTS driver context is NULL!");
+ return;
+ }
+
+ entry = devm_kzalloc(ipts->dev, sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return;
+
+ INIT_LIST_HEAD(&entry->list);
+
+ do {
+ ret = mei_cldev_recv(cldev, (u8 *)&entry->rsp, sizeof(entry->rsp));
+ } while (ret == -EINTR);
+
+ if (ret < 0) {
+ dev_err(ipts->dev, "Error while reading response: %ld\n", ret);
+ return;
+ }
+
+ if (ret == 0) {
+ dev_err(ipts->dev, "Received empty response\n");
+ return;
+ }
+
+ locked_list_add(&entry->list, &ipts->mei.messages, &ipts->mei.message_lock);
+ wake_up_all(&ipts->mei.message_queue);
+}
+
+static int ipts_mei_search(struct ipts_mei *mei, enum ipts_command_code code,
+ struct ipts_response *rsp)
+{
+ struct ipts_mei_message *entry = NULL;
+
+ if (!mei)
+ return -EFAULT;
+
+ if (!rsp)
+ return -EFAULT;
+
+ down_read(&mei->message_lock);
+
+ /*
+ * Iterate over the list of received messages, and check if there is one
+ * matching the requested command code.
+ */
+ list_for_each_entry(entry, &mei->messages, list) {
+ if (entry->rsp.cmd == code)
+ break;
+ }
+
+ up_read(&mei->message_lock);
+
+ /*
+ * If entry is not the list head, this means that the loop above has been stopped early,
+ * and that we found a matching element. We drop the message from the list and return it.
+ */
+ if (!list_entry_is_head(entry, &mei->messages, list)) {
+ locked_list_del(&entry->list, &mei->message_lock);
+
+ *rsp = entry->rsp;
+ devm_kfree(&mei->cldev->dev, entry);
+
+ return 0;
+ }
+
+ return -EAGAIN;
+}
+
+int ipts_mei_recv(struct ipts_mei *mei, enum ipts_command_code code, struct ipts_response *rsp,
+ u64 timeout)
+{
+ int ret = 0;
+
+ if (!mei)
+ return -EFAULT;
+
+ /*
+ * A timeout of 0 means check and return immideately.
+ */
+ if (timeout == 0)
+ return ipts_mei_search(mei, code, rsp);
+
+ /*
+ * A timeout of less than 0 means to wait forever.
+ */
+ if (timeout < 0) {
+ wait_event(mei->message_queue, ipts_mei_search(mei, code, rsp) == 0);
+ return 0;
+ }
+
+ ret = wait_event_timeout(mei->message_queue, ipts_mei_search(mei, code, rsp) == 0,
+ msecs_to_jiffies(timeout));
+
+ if (ret > 0)
+ return 0;
+
+ return -EAGAIN;
+}
+
+int ipts_mei_send(struct ipts_mei *mei, void *data, size_t length)
+{
+ int ret = 0;
+
+ if (!mei)
+ return -EFAULT;
+
+ if (!mei->cldev)
+ return -EFAULT;
+
+ if (!data)
+ return -EFAULT;
+
+ do {
+ ret = mei_cldev_send(mei->cldev, (u8 *)data, length);
+ } while (ret == -EINTR);
+
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+int ipts_mei_init(struct ipts_mei *mei, struct mei_cl_device *cldev)
+{
+ if (!mei)
+ return -EFAULT;
+
+ if (!cldev)
+ return -EFAULT;
+
+ mei->cldev = cldev;
+
+ INIT_LIST_HEAD(&mei->messages);
+ init_waitqueue_head(&mei->message_queue);
+ init_rwsem(&mei->message_lock);
+
+ mei_cldev_register_rx_cb(cldev, ipts_mei_incoming);
+
+ return 0;
+}
diff --git a/drivers/hid/ipts/mei.h b/drivers/hid/ipts/mei.h
new file mode 100644
index 000000000000..973bade6b0fd
--- /dev/null
+++ b/drivers/hid/ipts/mei.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_MEI_H
+#define IPTS_MEI_H
+
+#include <linux/list.h>
+#include <linux/mei_cl_bus.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "spec-device.h"
+
+struct ipts_mei_message {
+ struct list_head list;
+ struct ipts_response rsp;
+};
+
+struct ipts_mei {
+ struct mei_cl_device *cldev;
+
+ struct list_head messages;
+
+ wait_queue_head_t message_queue;
+ struct rw_semaphore message_lock;
+};
+
+/**
+ * ipts_mei_recv() - Receive data from a MEI device.
+ * @mei: The IPTS MEI device context.
+ * @code: The IPTS command code to look for.
+ * @rsp: The address that the received data will be copied to.
+ * @timeout: How many milliseconds the function will wait at most.
+ *
+ * A negative timeout means to wait forever.
+ *
+ * Returns: 0 on success, <0 on error, -EAGAIN if no response has been received.
+ */
+int ipts_mei_recv(struct ipts_mei *mei, enum ipts_command_code code, struct ipts_response *rsp,
+ u64 timeout);
+
+/**
+ * ipts_mei_send() - Send data to a MEI device.
+ * @ipts: The IPTS MEI device context.
+ * @data: The data to send.
+ * @size: The size of the data.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_mei_send(struct ipts_mei *mei, void *data, size_t length);
+
+/**
+ * ipts_mei_init() - Initialize the MEI device context.
+ * @mei: The MEI device context to initialize.
+ * @cldev: The MEI device the context will be bound to.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_mei_init(struct ipts_mei *mei, struct mei_cl_device *cldev);
+
+#endif /* IPTS_MEI_H */
diff --git a/drivers/hid/ipts/receiver.c b/drivers/hid/ipts/receiver.c
new file mode 100644
index 000000000000..ef66c3c9db80
--- /dev/null
+++ b/drivers/hid/ipts/receiver.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/time64.h>
+#include <linux/timekeeping.h>
+#include <linux/types.h>
+
+#include "cmd.h"
+#include "context.h"
+#include "control.h"
+#include "hid.h"
+#include "resources.h"
+#include "spec-device.h"
+#include "thread.h"
+
+static void ipts_receiver_next_doorbell(struct ipts_context *ipts)
+{
+ u32 *doorbell = (u32 *)ipts->resources.doorbell.address;
+ *doorbell = *doorbell + 1;
+}
+
+static u32 ipts_receiver_current_doorbell(struct ipts_context *ipts)
+{
+ u32 *doorbell = (u32 *)ipts->resources.doorbell.address;
+ return *doorbell;
+}
+
+static void ipts_receiver_backoff(time64_t last, u32 n)
+{
+ /*
+ * If the last change was less than n seconds ago,
+ * sleep for a shorter period so that new data can be
+ * processed quickly. If there was no change for more than
+ * n seconds, sleep longer to avoid wasting CPU cycles.
+ */
+ if (last + n > ktime_get_seconds())
+ usleep_range(1 * USEC_PER_MSEC, 5 * USEC_PER_MSEC);
+ else
+ msleep(200);
+}
+
+static int ipts_receiver_event_loop(struct ipts_thread *thread)
+{
+ int ret = 0;
+ u32 buffer = 0;
+
+ struct ipts_context *ipts = NULL;
+ time64_t last = ktime_get_seconds();
+
+ if (!thread)
+ return -EFAULT;
+
+ ipts = thread->data;
+
+ if (!ipts)
+ return -EFAULT;
+
+ dev_info(ipts->dev, "IPTS running in event mode\n");
+
+ while (!ipts_thread_should_stop(thread)) {
+ int i = 0;
+
+ for (i = 0; i < IPTS_BUFFERS; i++) {
+ ret = ipts_control_wait_data(ipts, false);
+ if (ret == -EAGAIN)
+ break;
+
+ if (ret) {
+ dev_err(ipts->dev, "Failed to wait for data: %d\n", ret);
+ continue;
+ }
+
+ buffer = ipts_receiver_current_doorbell(ipts) % IPTS_BUFFERS;
+ ipts_receiver_next_doorbell(ipts);
+
+ ret = ipts_hid_input_data(ipts, buffer);
+ if (ret)
+ dev_err(ipts->dev, "Failed to process buffer: %d\n", ret);
+
+ ret = ipts_control_refill_buffer(ipts, buffer);
+ if (ret)
+ dev_err(ipts->dev, "Failed to send feedback: %d\n", ret);
+
+ ret = ipts_control_request_data(ipts);
+ if (ret)
+ dev_err(ipts->dev, "Failed to request data: %d\n", ret);
+
+ last = ktime_get_seconds();
+ }
+
+ ipts_receiver_backoff(last, 5);
+ }
+
+ ret = ipts_control_request_flush(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to request flush: %d\n", ret);
+ return ret;
+ }
+
+ ret = ipts_control_wait_data(ipts, true);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to wait for data: %d\n", ret);
+
+ if (ret != -EAGAIN)
+ return ret;
+ else
+ return 0;
+ }
+
+ ret = ipts_control_wait_flush(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to wait for flush: %d\n", ret);
+
+ if (ret != -EAGAIN)
+ return ret;
+ else
+ return 0;
+ }
+
+ return 0;
+}
+
+static int ipts_receiver_poll_loop(struct ipts_thread *thread)
+{
+ int ret = 0;
+ u32 buffer = 0;
+
+ u32 doorbell = 0;
+ u32 lastdb = 0;
+
+ struct ipts_context *ipts = NULL;
+ time64_t last = ktime_get_seconds();
+
+ if (!thread)
+ return -EFAULT;
+
+ ipts = thread->data;
+
+ if (!ipts)
+ return -EFAULT;
+
+ dev_info(ipts->dev, "IPTS running in poll mode\n");
+
+ while (true) {
+ if (ipts_thread_should_stop(thread)) {
+ ret = ipts_control_request_flush(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to request flush: %d\n", ret);
+ return ret;
+ }
+ }
+
+ doorbell = ipts_receiver_current_doorbell(ipts);
+
+ /*
+ * After filling up one of the data buffers, IPTS will increment
+ * the doorbell. The value of the doorbell stands for the *next*
+ * buffer that IPTS is going to fill.
+ */
+ while (lastdb != doorbell) {
+ buffer = lastdb % IPTS_BUFFERS;
+
+ ret = ipts_hid_input_data(ipts, buffer);
+ if (ret)
+ dev_err(ipts->dev, "Failed to process buffer: %d\n", ret);
+
+ ret = ipts_control_refill_buffer(ipts, buffer);
+ if (ret)
+ dev_err(ipts->dev, "Failed to send feedback: %d\n", ret);
+
+ last = ktime_get_seconds();
+ lastdb++;
+ }
+
+ if (ipts_thread_should_stop(thread))
+ break;
+
+ ipts_receiver_backoff(last, 5);
+ }
+
+ ret = ipts_control_wait_data(ipts, true);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to wait for data: %d\n", ret);
+
+ if (ret != -EAGAIN)
+ return ret;
+ else
+ return 0;
+ }
+
+ ret = ipts_control_wait_flush(ipts);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to wait for flush: %d\n", ret);
+
+ if (ret != -EAGAIN)
+ return ret;
+ else
+ return 0;
+ }
+
+ return 0;
+}
+
+int ipts_receiver_start(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ if (ipts->mode == IPTS_MODE_EVENT) {
+ ret = ipts_thread_start(&ipts->receiver_loop, ipts_receiver_event_loop, ipts,
+ "ipts_event");
+ } else if (ipts->mode == IPTS_MODE_POLL) {
+ ret = ipts_thread_start(&ipts->receiver_loop, ipts_receiver_poll_loop, ipts,
+ "ipts_poll");
+ } else {
+ ret = -EINVAL;
+ }
+
+ if (ret) {
+ dev_err(ipts->dev, "Failed to start receiver loop: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+int ipts_receiver_stop(struct ipts_context *ipts)
+{
+ int ret = 0;
+
+ if (!ipts)
+ return -EFAULT;
+
+ ret = ipts_thread_stop(&ipts->receiver_loop);
+ if (ret) {
+ dev_err(ipts->dev, "Failed to stop receiver loop: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
diff --git a/drivers/hid/ipts/receiver.h b/drivers/hid/ipts/receiver.h
new file mode 100644
index 000000000000..3de7da62d40c
--- /dev/null
+++ b/drivers/hid/ipts/receiver.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_RECEIVER_H
+#define IPTS_RECEIVER_H
+
+#include "context.h"
+
+int ipts_receiver_start(struct ipts_context *ipts);
+int ipts_receiver_stop(struct ipts_context *ipts);
+
+#endif /* IPTS_RECEIVER_H */
diff --git a/drivers/hid/ipts/resources.c b/drivers/hid/ipts/resources.c
new file mode 100644
index 000000000000..cc14653b2a9f
--- /dev/null
+++ b/drivers/hid/ipts/resources.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "desc.h"
+#include "resources.h"
+#include "spec-device.h"
+
+static int ipts_resources_alloc_buffer(struct ipts_buffer *buffer, struct device *dev, size_t size)
+{
+ if (!buffer)
+ return -EFAULT;
+
+ if (buffer->address)
+ return 0;
+
+ buffer->address = dma_alloc_coherent(dev, size, &buffer->dma_address, GFP_KERNEL);
+
+ if (!buffer->address)
+ return -ENOMEM;
+
+ buffer->size = size;
+ buffer->device = dev;
+
+ return 0;
+}
+
+static void ipts_resources_free_buffer(struct ipts_buffer *buffer)
+{
+ if (!buffer->address)
+ return;
+
+ dma_free_coherent(buffer->device, buffer->size, buffer->address, buffer->dma_address);
+
+ buffer->address = NULL;
+ buffer->size = 0;
+
+ buffer->dma_address = 0;
+ buffer->device = NULL;
+}
+
+int ipts_resources_init(struct ipts_resources *res, struct device *dev, size_t ds, size_t fs)
+{
+ int ret = 0;
+
+ /*
+ * Some compilers (AOSP clang) complain about a redefined
+ * variable when this is declared inside of the for loop.
+ */
+ int i = 0;
+
+ if (!res)
+ return -EFAULT;
+
+ for (i = 0; i < IPTS_BUFFERS; i++) {
+ ret = ipts_resources_alloc_buffer(&res->data[i], dev, ds);
+ if (ret)
+ goto err;
+ }
+
+ for (i = 0; i < IPTS_BUFFERS; i++) {
+ ret = ipts_resources_alloc_buffer(&res->feedback[i], dev, fs);
+ if (ret)
+ goto err;
+ }
+
+ ret = ipts_resources_alloc_buffer(&res->doorbell, dev, sizeof(u32));
+ if (ret)
+ goto err;
+
+ ret = ipts_resources_alloc_buffer(&res->workqueue, dev, sizeof(u32));
+ if (ret)
+ goto err;
+
+ ret = ipts_resources_alloc_buffer(&res->hid2me, dev, fs);
+ if (ret)
+ goto err;
+
+ ret = ipts_resources_alloc_buffer(&res->descriptor, dev, ds + 8);
+ if (ret)
+ goto err;
+
+ if (!res->report.address) {
+ res->report.size = IPTS_HID_REPORT_DATA_SIZE;
+ res->report.address = kzalloc(res->report.size, GFP_KERNEL);
+
+ if (!res->report.address) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ }
+
+ return 0;
+
+err:
+
+ ipts_resources_free(res);
+ return ret;
+}
+
+int ipts_resources_free(struct ipts_resources *res)
+{
+ int i = 0;
+
+ if (!res)
+ return -EFAULT;
+
+ for (i = 0; i < IPTS_BUFFERS; i++)
+ ipts_resources_free_buffer(&res->data[i]);
+
+ for (i = 0; i < IPTS_BUFFERS; i++)
+ ipts_resources_free_buffer(&res->feedback[i]);
+
+ ipts_resources_free_buffer(&res->doorbell);
+ ipts_resources_free_buffer(&res->workqueue);
+ ipts_resources_free_buffer(&res->hid2me);
+ ipts_resources_free_buffer(&res->descriptor);
+
+ kfree(res->report.address);
+ res->report.address = NULL;
+ res->report.size = 0;
+
+ return 0;
+}
diff --git a/drivers/hid/ipts/resources.h b/drivers/hid/ipts/resources.h
new file mode 100644
index 000000000000..2068e13285f0
--- /dev/null
+++ b/drivers/hid/ipts/resources.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_RESOURCES_H
+#define IPTS_RESOURCES_H
+
+#include <linux/device.h>
+#include <linux/types.h>
+
+#include "spec-device.h"
+
+struct ipts_buffer {
+ u8 *address;
+ size_t size;
+
+ dma_addr_t dma_address;
+ struct device *device;
+};
+
+struct ipts_resources {
+ struct ipts_buffer data[IPTS_BUFFERS];
+ struct ipts_buffer feedback[IPTS_BUFFERS];
+
+ struct ipts_buffer doorbell;
+ struct ipts_buffer workqueue;
+ struct ipts_buffer hid2me;
+
+ struct ipts_buffer descriptor;
+
+ // Buffer for synthesizing HID reports
+ struct ipts_buffer report;
+};
+
+int ipts_resources_init(struct ipts_resources *res, struct device *dev, size_t ds, size_t fs);
+int ipts_resources_free(struct ipts_resources *res);
+
+#endif /* IPTS_RESOURCES_H */
diff --git a/drivers/hid/ipts/spec-data.h b/drivers/hid/ipts/spec-data.h
new file mode 100644
index 000000000000..e8dd98895a7e
--- /dev/null
+++ b/drivers/hid/ipts/spec-data.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_SPEC_DATA_H
+#define IPTS_SPEC_DATA_H
+
+#include <linux/build_bug.h>
+#include <linux/types.h>
+
+/**
+ * enum ipts_feedback_cmd_type - Commands that can be executed on the sensor through feedback.
+ */
+enum ipts_feedback_cmd_type {
+ IPTS_FEEDBACK_CMD_TYPE_NONE = 0,
+ IPTS_FEEDBACK_CMD_TYPE_SOFT_RESET = 1,
+ IPTS_FEEDBACK_CMD_TYPE_GOTO_ARMED = 2,
+ IPTS_FEEDBACK_CMD_TYPE_GOTO_SENSING = 3,
+ IPTS_FEEDBACK_CMD_TYPE_GOTO_SLEEP = 4,
+ IPTS_FEEDBACK_CMD_TYPE_GOTO_DOZE = 5,
+ IPTS_FEEDBACK_CMD_TYPE_HARD_RESET = 6,
+};
+
+/**
+ * enum ipts_feedback_data_type - Defines what data a feedback buffer contains.
+ * @IPTS_FEEDBACK_DATA_TYPE_VENDOR: The buffer contains vendor specific feedback.
+ * @IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES: The buffer contains a HID set features report.
+ * @IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES: The buffer contains a HID get features report.
+ * @IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT: The buffer contains a HID output report.
+ * @IPTS_FEEDBACK_DATA_TYPE_STORE_DATA: The buffer contains calibration data for the sensor.
+ */
+enum ipts_feedback_data_type {
+ IPTS_FEEDBACK_DATA_TYPE_VENDOR = 0,
+ IPTS_FEEDBACK_DATA_TYPE_SET_FEATURES = 1,
+ IPTS_FEEDBACK_DATA_TYPE_GET_FEATURES = 2,
+ IPTS_FEEDBACK_DATA_TYPE_OUTPUT_REPORT = 3,
+ IPTS_FEEDBACK_DATA_TYPE_STORE_DATA = 4,
+};
+
+/**
+ * struct ipts_feedback_header - Header that is prefixed to the data in a feedback buffer.
+ * @cmd_type: A command that should be executed on the sensor.
+ * @size: The size of the payload to be written.
+ * @buffer: The ID of the buffer that contains this feedback data.
+ * @protocol: The protocol version of the EDS.
+ * @data_type: The type of data that the buffer contains.
+ * @spi_offset: The offset at which to write the payload data to the sensor.
+ * @payload: Payload for the feedback command, or 0 if no payload is sent.
+ */
+struct ipts_feedback_header {
+ enum ipts_feedback_cmd_type cmd_type;
+ u32 size;
+ u32 buffer;
+ u32 protocol;
+ enum ipts_feedback_data_type data_type;
+ u32 spi_offset;
+ u8 reserved[40];
+ u8 payload[];
+} __packed;
+
+static_assert(sizeof(struct ipts_feedback_header) == 64);
+
+/**
+ * enum ipts_data_type - Defines what type of data a buffer contains.
+ * @IPTS_DATA_TYPE_FRAME: Raw data frame.
+ * @IPTS_DATA_TYPE_ERROR: Error data.
+ * @IPTS_DATA_TYPE_VENDOR: Vendor specific data.
+ * @IPTS_DATA_TYPE_HID: A HID report.
+ * @IPTS_DATA_TYPE_GET_FEATURES: The response to a GET_FEATURES HID2ME command.
+ */
+enum ipts_data_type {
+ IPTS_DATA_TYPE_FRAME = 0x00,
+ IPTS_DATA_TYPE_ERROR = 0x01,
+ IPTS_DATA_TYPE_VENDOR = 0x02,
+ IPTS_DATA_TYPE_HID = 0x03,
+ IPTS_DATA_TYPE_GET_FEATURES = 0x04,
+ IPTS_DATA_TYPE_DESCRIPTOR = 0x05,
+};
+
+/**
+ * struct ipts_data_header - Header that is prefixed to the data in a data buffer.
+ * @type: What data the buffer contains.
+ * @size: How much data the buffer contains.
+ * @buffer: Which buffer the data is in.
+ */
+struct ipts_data_header {
+ enum ipts_data_type type;
+ u32 size;
+ u32 buffer;
+ u8 reserved[52];
+ u8 data[];
+} __packed;
+
+static_assert(sizeof(struct ipts_data_header) == 64);
+
+#endif /* IPTS_SPEC_DATA_H */
diff --git a/drivers/hid/ipts/spec-device.h b/drivers/hid/ipts/spec-device.h
new file mode 100644
index 000000000000..41845f9d9025
--- /dev/null
+++ b/drivers/hid/ipts/spec-device.h
@@ -0,0 +1,290 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_SPEC_DEVICE_H
+#define IPTS_SPEC_DEVICE_H
+
+#include <linux/build_bug.h>
+#include <linux/types.h>
+
+/*
+ * The amount of buffers that IPTS can use for data transfer.
+ */
+#define IPTS_BUFFERS 16
+
+/*
+ * The buffer ID that is used for HID2ME feedback
+ */
+#define IPTS_HID2ME_BUFFER IPTS_BUFFERS
+
+/**
+ * enum ipts_command - Commands that can be sent to the IPTS hardware.
+ * @IPTS_CMD_GET_DEVICE_INFO: Retrieves vendor information from the device.
+ * @IPTS_CMD_SET_MODE: Changes the mode that the device will operate in.
+ * @IPTS_CMD_SET_MEM_WINDOW: Configures memory buffers for passing data between device and driver.
+ * @IPTS_CMD_QUIESCE_IO: Stops the data flow from the device to the driver.
+ * @IPTS_CMD_READY_FOR_DATA: Informs the device that the driver is ready to receive data.
+ * @IPTS_CMD_FEEDBACK: Informs the device that a buffer was processed and can be refilled.
+ * @IPTS_CMD_CLEAR_MEM_WINDOW: Stops the data flow and clears the buffer addresses on the device.
+ * @IPTS_CMD_RESET_SENSOR: Resets the sensor to its default state.
+ * @IPTS_CMD_GET_DESCRIPTOR: Retrieves the HID descriptor of the device.
+ */
+enum ipts_command_code {
+ IPTS_CMD_GET_DEVICE_INFO = 0x01,
+ IPTS_CMD_SET_MODE = 0x02,
+ IPTS_CMD_SET_MEM_WINDOW = 0x03,
+ IPTS_CMD_QUIESCE_IO = 0x04,
+ IPTS_CMD_READY_FOR_DATA = 0x05,
+ IPTS_CMD_FEEDBACK = 0x06,
+ IPTS_CMD_CLEAR_MEM_WINDOW = 0x07,
+ IPTS_CMD_RESET_SENSOR = 0x0B,
+ IPTS_CMD_GET_DESCRIPTOR = 0x0F,
+};
+
+/**
+ * enum ipts_status - Possible status codes returned by the IPTS device.
+ * @IPTS_STATUS_SUCCESS: Operation completed successfully.
+ * @IPTS_STATUS_INVALID_PARAMS: Command contained an invalid payload.
+ * @IPTS_STATUS_ACCESS_DENIED: ME could not validate a buffer address.
+ * @IPTS_STATUS_CMD_SIZE_ERROR: Command contains an invalid payload.
+ * @IPTS_STATUS_NOT_READY: Buffer addresses have not been set.
+ * @IPTS_STATUS_REQUEST_OUTSTANDING: There is an outstanding command of the same type.
+ * @IPTS_STATUS_NO_SENSOR_FOUND: No sensor could be found.
+ * @IPTS_STATUS_OUT_OF_MEMORY: Not enough free memory for requested operation.
+ * @IPTS_STATUS_INTERNAL_ERROR: An unexpected error occurred.
+ * @IPTS_STATUS_SENSOR_DISABLED: The sensor has been disabled and must be reinitialized.
+ * @IPTS_STATUS_COMPAT_CHECK_FAIL: Compatibility revision check between sensor and ME failed.
+ * The host can ignore this error and attempt to continue.
+ * @IPTS_STATUS_SENSOR_EXPECTED_RESET: The sensor went through a reset initiated by the driver.
+ * @IPTS_STATUS_SENSOR_UNEXPECTED_RESET: The sensor went through an unexpected reset.
+ * @IPTS_STATUS_RESET_FAILED: Requested sensor reset failed to complete.
+ * @IPTS_STATUS_TIMEOUT: The operation timed out.
+ * @IPTS_STATUS_TEST_MODE_FAIL: Test mode pattern did not match expected values.
+ * @IPTS_STATUS_SENSOR_FAIL_FATAL: The sensor reported an error during reset sequence.
+ * Further progress is not possible.
+ * @IPTS_STATUS_SENSOR_FAIL_NONFATAL: The sensor reported an error during reset sequence.
+ * The driver can attempt to continue.
+ * @IPTS_STATUS_INVALID_DEVICE_CAPS: The device reported invalid capabilities.
+ * @IPTS_STATUS_QUIESCE_IO_IN_PROGRESS: Command cannot be completed until Quiesce IO is done.
+ */
+enum ipts_status {
+ IPTS_STATUS_SUCCESS = 0x00,
+ IPTS_STATUS_INVALID_PARAMS = 0x01,
+ IPTS_STATUS_ACCESS_DENIED = 0x02,
+ IPTS_STATUS_CMD_SIZE_ERROR = 0x03,
+ IPTS_STATUS_NOT_READY = 0x04,
+ IPTS_STATUS_REQUEST_OUTSTANDING = 0x05,
+ IPTS_STATUS_NO_SENSOR_FOUND = 0x06,
+ IPTS_STATUS_OUT_OF_MEMORY = 0x07,
+ IPTS_STATUS_INTERNAL_ERROR = 0x08,
+ IPTS_STATUS_SENSOR_DISABLED = 0x09,
+ IPTS_STATUS_COMPAT_CHECK_FAIL = 0x0A,
+ IPTS_STATUS_SENSOR_EXPECTED_RESET = 0x0B,
+ IPTS_STATUS_SENSOR_UNEXPECTED_RESET = 0x0C,
+ IPTS_STATUS_RESET_FAILED = 0x0D,
+ IPTS_STATUS_TIMEOUT = 0x0E,
+ IPTS_STATUS_TEST_MODE_FAIL = 0x0F,
+ IPTS_STATUS_SENSOR_FAIL_FATAL = 0x10,
+ IPTS_STATUS_SENSOR_FAIL_NONFATAL = 0x11,
+ IPTS_STATUS_INVALID_DEVICE_CAPS = 0x12,
+ IPTS_STATUS_QUIESCE_IO_IN_PROGRESS = 0x13,
+};
+
+/**
+ * struct ipts_command - Message that is sent to the device for calling a command.
+ * @cmd: The command that will be called.
+ * @payload: Payload containing parameters for the called command.
+ */
+struct ipts_command {
+ enum ipts_command_code cmd;
+ u8 payload[320];
+} __packed;
+
+static_assert(sizeof(struct ipts_command) == 324);
+
+/**
+ * enum ipts_mode - Configures what data the device produces and how its sent.
+ * @IPTS_MODE_EVENT: The device will send an event once a buffer was filled.
+ * Older devices will return singletouch data in this mode.
+ * @IPTS_MODE_POLL: The device will notify the driver by incrementing the doorbell value.
+ * Older devices will return multitouch data in this mode.
+ */
+enum ipts_mode {
+ IPTS_MODE_EVENT = 0x00,
+ IPTS_MODE_POLL = 0x01,
+};
+
+/**
+ * struct ipts_set_mode - Payload for the SET_MODE command.
+ * @mode: Changes the mode that IPTS will operate in.
+ */
+struct ipts_set_mode {
+ enum ipts_mode mode;
+ u8 reserved[12];
+} __packed;
+
+static_assert(sizeof(struct ipts_set_mode) == 16);
+
+#define IPTS_WORKQUEUE_SIZE 8192
+#define IPTS_WORKQUEUE_ITEM_SIZE 16
+
+/**
+ * struct ipts_mem_window - Payload for the SET_MEM_WINDOW command.
+ * @data_addr_lower: Lower 32 bits of the data buffer addresses.
+ * @data_addr_upper: Upper 32 bits of the data buffer addresses.
+ * @workqueue_addr_lower: Lower 32 bits of the workqueue buffer address.
+ * @workqueue_addr_upper: Upper 32 bits of the workqueue buffer address.
+ * @doorbell_addr_lower: Lower 32 bits of the doorbell buffer address.
+ * @doorbell_addr_upper: Upper 32 bits of the doorbell buffer address.
+ * @feedbackaddr_lower: Lower 32 bits of the feedback buffer addresses.
+ * @feedbackaddr_upper: Upper 32 bits of the feedback buffer addresses.
+ * @hid2me_addr_lower: Lower 32 bits of the hid2me buffer address.
+ * @hid2me_addr_upper: Upper 32 bits of the hid2me buffer address.
+ * @hid2me_size: Size of the hid2me feedback buffer.
+ * @workqueue_item_size: Magic value. Must be 16.
+ * @workqueue_size: Magic value. Must be 8192.
+ *
+ * The workqueue related items in this struct are required for using
+ * GuC submission with binary processing firmware. Since this driver does
+ * not use GuC submission and instead exports raw data to userspace, these
+ * items are not actually used, but they need to be allocated and passed
+ * to the device, otherwise initialization will fail.
+ */
+struct ipts_mem_window {
+ u32 data_addr_lower[IPTS_BUFFERS];
+ u32 data_addr_upper[IPTS_BUFFERS];
+ u32 workqueue_addr_lower;
+ u32 workqueue_addr_upper;
+ u32 doorbell_addr_lower;
+ u32 doorbell_addr_upper;
+ u32 feedback_addr_lower[IPTS_BUFFERS];
+ u32 feedback_addr_upper[IPTS_BUFFERS];
+ u32 hid2me_addr_lower;
+ u32 hid2me_addr_upper;
+ u32 hid2me_size;
+ u8 reserved1;
+ u8 workqueue_item_size;
+ u16 workqueue_size;
+ u8 reserved[32];
+} __packed;
+
+static_assert(sizeof(struct ipts_mem_window) == 320);
+
+/**
+ * struct ipts_quiesce_io - Payload for the QUIESCE_IO command.
+ */
+struct ipts_quiesce_io {
+ u8 reserved[12];
+} __packed;
+
+static_assert(sizeof(struct ipts_quiesce_io) == 12);
+
+/**
+ * struct ipts_feedback - Payload for the FEEDBACK command.
+ * @buffer: The buffer that the device should refill.
+ */
+struct ipts_feedback {
+ u32 buffer;
+ u8 reserved[12];
+} __packed;
+
+static_assert(sizeof(struct ipts_feedback) == 16);
+
+/**
+ * enum ipts_reset_type - Possible ways of resetting the device.
+ * @IPTS_RESET_TYPE_HARD: Perform hardware reset using GPIO pin.
+ * @IPTS_RESET_TYPE_SOFT: Perform software reset using SPI command.
+ */
+enum ipts_reset_type {
+ IPTS_RESET_TYPE_HARD = 0x00,
+ IPTS_RESET_TYPE_SOFT = 0x01,
+};
+
+/**
+ * struct ipts_reset - Payload for the RESET_SENSOR command.
+ * @type: How the device should get reset.
+ */
+struct ipts_reset_sensor {
+ enum ipts_reset_type type;
+ u8 reserved[4];
+} __packed;
+
+static_assert(sizeof(struct ipts_reset_sensor) == 8);
+
+/**
+ * struct ipts_get_descriptor - Payload for the GET_DESCRIPTOR command.
+ * @addr_lower: The lower 32 bits of the descriptor buffer address.
+ * @addr_upper: The upper 32 bits of the descriptor buffer address.
+ * @magic: A magic value. Must be 8.
+ */
+struct ipts_get_descriptor {
+ u32 addr_lower;
+ u32 addr_upper;
+ u32 magic;
+ u8 reserved[12];
+} __packed;
+
+static_assert(sizeof(struct ipts_get_descriptor) == 24);
+
+/*
+ * The type of a response is indicated by a
+ * command code, with the most significant bit flipped to 1.
+ */
+#define IPTS_RSP_BIT BIT(31)
+
+/**
+ * struct ipts_response - Data returned from the device in response to a command.
+ * @cmd: The command that this response answers (IPTS_RSP_BIT will be 1).
+ * @status: The return code of the command.
+ * @payload: The data that was produced by the command.
+ */
+struct ipts_response {
+ enum ipts_command_code cmd;
+ enum ipts_status status;
+ u8 payload[80];
+} __packed;
+
+static_assert(sizeof(struct ipts_response) == 88);
+
+/**
+ * struct ipts_device_info - Vendor information of the IPTS device.
+ * @vendor: Vendor ID of this device.
+ * @product: Product ID of this device.
+ * @hw_version: Hardware revision of this device.
+ * @fw_version: Firmware revision of this device.
+ * @data_size: Requested size for a data buffer.
+ * @feedback_size: Requested size for a feedback buffer.
+ * @mode: Mode that the device currently operates in.
+ * @max_contacts: Maximum amount of concurrent touches the sensor can process.
+ * @sensor_min_eds: The minimum EDS version supported by the sensor.
+ * @sensor_max_eds: The maximum EDS version supported by the sensor.
+ * @me_min_eds: The minimum EDS version supported by the ME for communicating with the sensor.
+ * @me_max_eds: The maximum EDS version supported by the ME for communicating with the sensor.
+ * @intf_eds: The EDS version implemented by the interface between ME and host.
+ */
+struct ipts_device_info {
+ u16 vendor;
+ u16 product;
+ u32 hw_version;
+ u32 fw_version;
+ u32 data_size;
+ u32 feedback_size;
+ enum ipts_mode mode;
+ u8 max_contacts;
+ u8 reserved1[3];
+ u8 sensor_min_eds;
+ u8 sensor_maj_eds;
+ u8 me_min_eds;
+ u8 me_maj_eds;
+ u8 intf_eds;
+ u8 reserved2[11];
+} __packed;
+
+static_assert(sizeof(struct ipts_device_info) == 44);
+
+#endif /* IPTS_SPEC_DEVICE_H */
diff --git a/drivers/hid/ipts/spec-hid.h b/drivers/hid/ipts/spec-hid.h
new file mode 100644
index 000000000000..5a58d4a0a610
--- /dev/null
+++ b/drivers/hid/ipts/spec-hid.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2020-2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_SPEC_HID_H
+#define IPTS_SPEC_HID_H
+
+#include <linux/build_bug.h>
+#include <linux/types.h>
+
+/*
+ * Made-up type for passing raw IPTS data in a HID report.
+ */
+#define IPTS_HID_FRAME_TYPE_RAW 0xEE
+
+/**
+ * struct ipts_hid_frame - Header that is prefixed to raw IPTS data wrapped in a HID report.
+ * @size: Size of the data inside the report, including this header.
+ * @type: What type of data does this report contain.
+ */
+struct ipts_hid_header {
+ u32 size;
+ u8 reserved1;
+ u8 type;
+ u8 reserved2;
+ u8 data[];
+} __packed;
+
+static_assert(sizeof(struct ipts_hid_header) == 7);
+
+#endif /* IPTS_SPEC_HID_H */
diff --git a/drivers/hid/ipts/thread.c b/drivers/hid/ipts/thread.c
new file mode 100644
index 000000000000..355e92bea26f
--- /dev/null
+++ b/drivers/hid/ipts/thread.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+
+#include "thread.h"
+
+bool ipts_thread_should_stop(struct ipts_thread *thread)
+{
+ if (!thread)
+ return false;
+
+ return READ_ONCE(thread->should_stop);
+}
+
+static int ipts_thread_runner(void *data)
+{
+ int ret = 0;
+ struct ipts_thread *thread = data;
+
+ if (!thread)
+ return -EFAULT;
+
+ if (!thread->threadfn)
+ return -EFAULT;
+
+ ret = thread->threadfn(thread);
+ complete_all(&thread->done);
+
+ return ret;
+}
+
+int ipts_thread_start(struct ipts_thread *thread, int (*threadfn)(struct ipts_thread *thread),
+ void *data, const char *name)
+{
+ if (!thread)
+ return -EFAULT;
+
+ if (!threadfn)
+ return -EFAULT;
+
+ init_completion(&thread->done);
+
+ thread->data = data;
+ thread->should_stop = false;
+ thread->threadfn = threadfn;
+
+ thread->thread = kthread_run(ipts_thread_runner, thread, name);
+ return PTR_ERR_OR_ZERO(thread->thread);
+}
+
+int ipts_thread_stop(struct ipts_thread *thread)
+{
+ int ret = 0;
+
+ if (!thread)
+ return -EFAULT;
+
+ if (!thread->thread)
+ return 0;
+
+ WRITE_ONCE(thread->should_stop, true);
+
+ /*
+ * Make sure that the write has gone through before waiting.
+ */
+ wmb();
+
+ wait_for_completion(&thread->done);
+ ret = kthread_stop(thread->thread);
+
+ thread->thread = NULL;
+ thread->data = NULL;
+ thread->threadfn = NULL;
+
+ return ret;
+}
diff --git a/drivers/hid/ipts/thread.h b/drivers/hid/ipts/thread.h
new file mode 100644
index 000000000000..1f966b8b32c4
--- /dev/null
+++ b/drivers/hid/ipts/thread.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2023 Dorian Stoll
+ *
+ * Linux driver for Intel Precise Touch & Stylus
+ */
+
+#ifndef IPTS_THREAD_H
+#define IPTS_THREAD_H
+
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+
+/*
+ * This wrapper over kthread is necessary, because calling kthread_stop makes it impossible
+ * to issue MEI commands from that thread while it shuts itself down. By using a custom
+ * boolean variable and a completion object, we can call kthread_stop only when the thread
+ * already finished all of its work and has returned.
+ */
+struct ipts_thread {
+ struct task_struct *thread;
+
+ bool should_stop;
+ struct completion done;
+
+ void *data;
+ int (*threadfn)(struct ipts_thread *thread);
+};
+
+/**
+ * ipts_thread_should_stop() - Returns true if the thread is asked to terminate.
+ * @thread: The current thread.
+ *
+ * Returns: true if the thread should stop, false if not.
+ */
+bool ipts_thread_should_stop(struct ipts_thread *thread);
+
+/**
+ * ipts_thread_start() - Starts an IPTS thread.
+ * @thread: The thread to initialize and start.
+ * @threadfn: The function to execute.
+ * @data: An argument that will be passed to threadfn.
+ * @name: The name of the new thread.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int ipts_thread_start(struct ipts_thread *thread, int (*threadfn)(struct ipts_thread *thread),
+ void *data, const char name[]);
+
+/**
+ * ipts_thread_stop() - Asks the thread to terminate and waits until it has finished.
+ * @thread: The thread that should stop.
+ *
+ * Returns: The return value of the thread function.
+ */
+int ipts_thread_stop(struct ipts_thread *thread);
+
+#endif /* IPTS_THREAD_H */
--
2.41.0
