Add HID Low level driver callbacks and hid probe function to register
QucikI2C as a HID driver, and external touch device as a HID device.

Co-developed-by: Xinpeng Sun <xinpeng.sun@intel.com>
Signed-off-by: Xinpeng Sun <xinpeng.sun@intel.com>
Signed-off-by: Even Xu <even.xu@intel.com>
Tested-by: Rui Zhang <rui1.zhang@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/intel-thc-hid/Makefile            |   1 +
 .../intel-quicki2c/quicki2c-dev.h             |  11 ++
 .../intel-quicki2c/quicki2c-hid.c             | 142 ++++++++++++++++++
 .../intel-quicki2c/quicki2c-hid.h             |  14 ++
 include/linux/hid-over-i2c.h                  |  44 ++++++
 5 files changed, 212 insertions(+)
 create mode 100644 drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.c
 create mode 100644 drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.h
 create mode 100644 include/linux/hid-over-i2c.h

diff --git a/drivers/hid/intel-thc-hid/Makefile b/drivers/hid/intel-thc-hid/Makefile
index 4d4f02e1c415..91bde6d6aa14 100644
--- a/drivers/hid/intel-thc-hid/Makefile
+++ b/drivers/hid/intel-thc-hid/Makefile
@@ -16,5 +16,6 @@ intel-quickspi-objs += intel-quickspi/quickspi-protocol.o
 
 obj-$(CONFIG_INTEL_QUICKI2C) += intel-quicki2c.o
 intel-quicki2c-objs += intel-quicki2c/pci-quicki2c.o
+intel-quicki2c-objs += intel-quicki2c/quicki2c-hid.o
 
 ccflags-y += -I $(src)/intel-thc
diff --git a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
index 370faad744f5..7cdbd7f4acd3 100644
--- a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
+++ b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-dev.h
@@ -4,6 +4,8 @@
 #ifndef _QUICKI2C_DEV_H_
 #define _QUICKI2C_DEV_H_
 
+#include <linux/hid-over-i2c.h>
+
 #define THC_LNL_DEVICE_ID_I2C_PORT1	0xA848
 #define THC_LNL_DEVICE_ID_I2C_PORT2	0xA84A
 
@@ -22,23 +24,32 @@ enum quicki2c_dev_state {
 struct device;
 struct pci_dev;
 struct thc_device;
+struct hid_device;
 
 /**
  * struct quicki2c_device -  THC QuickI2C device struct
  * @dev: point to kernel device
  * @pdev: point to PCI device
  * @thc_hw: point to THC device
+ * @hid_dev: point to hid device
  * @driver_data: point to quicki2c specific driver data
  * @state: THC I2C device state
  * @mem_addr: MMIO memory address
+ * @dev_desc: device descriptor for HIDI2C protocol
+ * @report_descriptor: store a copy of device report descriptor
  */
 struct quicki2c_device {
 	struct device *dev;
 	struct pci_dev *pdev;
 	struct thc_device *thc_hw;
+	struct hid_device *hid_dev;
 	enum quicki2c_dev_state state;
 
 	void __iomem *mem_addr;
+
+	struct hidi2c_dev_descriptor dev_desc;
+
+	u8 *report_descriptor;
 };
 
 #endif /* _QUICKI2C_DEV_H_ */
diff --git a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.c b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.c
new file mode 100644
index 000000000000..4236603f3f76
--- /dev/null
+++ b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.c
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2024 Intel Corporation */
+
+#include <linux/hid.h>
+#include <linux/input.h>
+
+#include "quicki2c-dev.h"
+#include "quicki2c-hid.h"
+
+/**
+ * quicki2c_hid_parse() - HID core parse() callback
+ *
+ * @hid: HID device instance
+ *
+ * This function gets called during call to hid_add_device
+ *
+ * Return: 0 on success and non zero on error.
+ */
+static int quicki2c_hid_parse(struct hid_device *hid)
+{
+	struct quicki2c_device *qcdev = hid->driver_data;
+
+	if (qcdev->report_descriptor)
+		return hid_parse_report(hid, qcdev->report_descriptor,
+					le16_to_cpu(qcdev->dev_desc.report_desc_len));
+
+	dev_err_once(qcdev->dev, "invalid report descriptor\n");
+	return -EINVAL;
+}
+
+static int quicki2c_hid_start(struct hid_device *hid)
+{
+	return 0;
+}
+
+static void quicki2c_hid_stop(struct hid_device *hid)
+{
+}
+
+static int quicki2c_hid_open(struct hid_device *hid)
+{
+	return 0;
+}
+
+static void quicki2c_hid_close(struct hid_device *hid)
+{
+}
+
+static int quicki2c_hid_raw_request(struct hid_device *hid,
+				    unsigned char reportnum,
+				    __u8 *buf, size_t len,
+				    unsigned char rtype, int reqtype)
+{
+	return 0;
+}
+
+static int quicki2c_hid_power(struct hid_device *hid, int lvl)
+{
+	return 0;
+}
+
+static struct hid_ll_driver quicki2c_hid_ll_driver = {
+	.parse = quicki2c_hid_parse,
+	.start = quicki2c_hid_start,
+	.stop = quicki2c_hid_stop,
+	.open = quicki2c_hid_open,
+	.close = quicki2c_hid_close,
+	.power = quicki2c_hid_power,
+	.raw_request = quicki2c_hid_raw_request,
+};
+
+/**
+ * quicki2c_hid_probe() - Register HID low level driver
+ *
+ * @qcdev: point to quicki2c device
+ *
+ * This function is used to allocate and add HID device.
+ *
+ * Return: 0 on success, non zero on error.
+ */
+int quicki2c_hid_probe(struct quicki2c_device *qcdev)
+{
+	struct hid_device *hid;
+	int ret;
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid))
+		return PTR_ERR(hid);
+
+	hid->ll_driver = &quicki2c_hid_ll_driver;
+	hid->bus = BUS_PCI;
+	hid->dev.parent = qcdev->dev;
+	hid->driver_data = qcdev;
+	hid->version = le16_to_cpu(qcdev->dev_desc.version_id);
+	hid->vendor = le16_to_cpu(qcdev->dev_desc.vendor_id);
+	hid->product = le16_to_cpu(qcdev->dev_desc.product_id);
+	snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X", "quicki2c-hid",
+		 hid->vendor, hid->product);
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		hid_destroy_device(hid);
+		return ret;
+	}
+
+	qcdev->hid_dev = hid;
+
+	return 0;
+}
+
+/**
+ * quicki2c_hid_remove() - Destroy HID device
+ *
+ * @qcdev: point to quicki2c device
+ *
+ * Return: 0 on success, non zero on error.
+ */
+void quicki2c_hid_remove(struct quicki2c_device *qcdev)
+{
+	hid_destroy_device(qcdev->hid_dev);
+}
+
+/**
+ * quicki2c_hid_send_report() - Send HID input report data to HID core
+ *
+ * @qcdev: point to quicki2c device
+ * @data: point to input report data buffer
+ * @data_len: the length of input report data
+ *
+ * Return: 0 on success, non zero on error.
+ */
+int quicki2c_hid_send_report(struct quicki2c_device *qcdev,
+			     void *data, size_t data_len)
+{
+	int ret;
+
+	ret = hid_input_report(qcdev->hid_dev, HID_INPUT_REPORT, data, data_len, 1);
+	if (ret)
+		dev_err(qcdev->dev, "Failed to send HID input report, ret = %d.\n", ret);
+
+	return ret;
+}
diff --git a/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.h b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.h
new file mode 100644
index 000000000000..e80df5f339fe
--- /dev/null
+++ b/drivers/hid/intel-thc-hid/intel-quicki2c/quicki2c-hid.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2024 Intel Corporation */
+
+#ifndef _QUICKI2C_HID_H_
+#define _QUICKI2C_HID_H_
+
+struct quicki2c_device;
+
+int quicki2c_hid_send_report(struct quicki2c_device *qcdev,
+			     void *data, size_t data_size);
+int quicki2c_hid_probe(struct quicki2c_device *qcdev);
+void quicki2c_hid_remove(struct quicki2c_device *qcdev);
+
+#endif /* _QUICKI2C_HID_H_ */
diff --git a/include/linux/hid-over-i2c.h b/include/linux/hid-over-i2c.h
new file mode 100644
index 000000000000..b70626723a38
--- /dev/null
+++ b/include/linux/hid-over-i2c.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright 2024 Intel Corporation */
+
+#ifndef _HID_OVER_I2C_H_
+#define _HID_OVER_I2C_H_
+
+/**
+ * struct hidi2c_dev_descriptor - HIDI2C device descriptor definition
+ * @dev_desc_len: The length of the complete device descriptor, fixed to 0x1E (30).
+ * @bcd_ver: The version number of the HIDI2C protocol supported.
+ *           In binary coded decimal (BCD) format.
+ * @report_desc_len: The length of the report descriptor
+ * @report_desc_reg: The register address to retrieve report descriptor
+ * @input_reg: the register address to retrieve input report
+ * @max_input_len: The length of the largest possible HID input (or feature) report
+ * @output_reg: the register address to send output report
+ * @max_output_len: The length of the largest output (or feature) report
+ * @cmd_reg: the register address to send command
+ * @data_reg: the register address to send command data
+ * @vendor_id: Device manufacturers vendor ID
+ * @product_id: Device unique model/product ID
+ * @version_id: Device’s unique version
+ * @reserved0: Reserved and should be 0
+ * @reserved1: Reserved and should be 0
+ */
+struct hidi2c_dev_descriptor {
+	__le16 dev_desc_len;
+	__le16 bcd_ver;
+	__le16 report_desc_len;
+	__le16 report_desc_reg;
+	__le16 input_reg;
+	__le16 max_input_len;
+	__le16 output_reg;
+	__le16 max_output_len;
+	__le16 cmd_reg;
+	__le16 data_reg;
+	__le16 vendor_id;
+	__le16 product_id;
+	__le16 version_id;
+	__le16 reserved0;
+	__le16 reserved1;
+} __packed;
+
+#endif /* _HID_OVER_I2C_H_ */
-- 
2.40.1