HID: intel-thc-hid: intel-quicki2c: Add HIDI2C protocol implementation

Intel QuickI2C driver uses THC hardware to accelerate HID over I2C
(HIDI2C) protocol flow.

This patch implements all data flows described in HID over I2C protocol
SPEC by using THC hardware layer APIs.

HID over I2C SPEC:
https://learn.microsoft.com/en-us/previous-versions/windows/hardware/design/dn642101(v=vs.85)

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>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Aaron Ma <aaron.ma@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/include/linux/hid-over-i2c.h b/include/linux/hid-over-i2c.h
index b70626723a38..3b1a0208a6b8 100644
--- a/include/linux/hid-over-i2c.h
+++ b/include/linux/hid-over-i2c.h
@@ -1,9 +1,80 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /* Copyright 2024 Intel Corporation */
 
+#include <linux/bits.h>
+
 #ifndef _HID_OVER_I2C_H_
 #define _HID_OVER_I2C_H_
 
+#define HIDI2C_REG_LEN		sizeof(__le16)
+
+/* Input report type definition in HIDI2C protocol */
+enum hidi2c_report_type {
+	HIDI2C_RESERVED = 0,
+	HIDI2C_INPUT,
+	HIDI2C_OUTPUT,
+	HIDI2C_FEATURE,
+};
+
+/* Power state type definition in HIDI2C protocol */
+enum hidi2c_power_state {
+	HIDI2C_ON,
+	HIDI2C_SLEEP,
+};
+
+/* Opcode type definition in HIDI2C protocol */
+enum hidi2c_opcode {
+	HIDI2C_RESET = 1,
+	HIDI2C_GET_REPORT,
+	HIDI2C_SET_REPORT,
+	HIDI2C_GET_IDLE,
+	HIDI2C_SET_IDLE,
+	HIDI2C_GET_PROTOCOL,
+	HIDI2C_SET_PROTOCOL,
+	HIDI2C_SET_POWER,
+};
+
+/**
+ * struct hidi2c_report_packet - Report packet definition in HIDI2C protocol
+ * @len: data field length
+ * @data: HIDI2C report packet data
+ */
+struct hidi2c_report_packet {
+	__le16 len;
+	u8 data[];
+} __packed;
+
+#define HIDI2C_LENGTH_LEN	sizeof(__le16)
+
+#define HIDI2C_PACKET_LEN(data_len)	((data_len) + HIDI2C_LENGTH_LEN)
+#define HIDI2C_DATA_LEN(pkt_len)	((pkt_len) - HIDI2C_LENGTH_LEN)
+
+#define HIDI2C_CMD_MAX_RI	0x0F
+
+/**
+ * HIDI2C command data packet - Command packet definition in HIDI2C protocol
+ * @report_id:		[0:3] report id (<15) for features or output reports
+ * @report_type:	[4:5] indicate report type, reference to hidi2c_report_type
+ * @reserved0:		[6:7] reserved bits
+ * @opcode:		[8:11] command operation code, reference to hidi2c_opcode
+ * @reserved1:		[12:15] reserved bits
+ * @report_id_optional: [23:16] appended 3rd byte.
+ *                      If the report_id in the low byte is set to the
+ *                      sentinel value (HIDI2C_CMD_MAX_RI), then this
+ *                      optional third byte represents the report id (>=15)
+ *                      Otherwise, not this 3rd byte.
+ */
+
+#define HIDI2C_CMD_LEN			sizeof(__le16)
+#define HIDI2C_CMD_LEN_OPT		(sizeof(__le16) + 1)
+#define HIDI2C_CMD_REPORT_ID		GENMASK(3, 0)
+#define HIDI2C_CMD_REPORT_TYPE		GENMASK(5, 4)
+#define HIDI2C_CMD_OPCODE		GENMASK(11, 8)
+#define HIDI2C_CMD_OPCODE		GENMASK(11, 8)
+#define HIDI2C_CMD_3RD_BYTE		GENMASK(23, 16)
+
+#define HIDI2C_HID_DESC_BCDVERSION	0x100
+
 /**
  * struct hidi2c_dev_descriptor - HIDI2C device descriptor definition
  * @dev_desc_len: The length of the complete device descriptor, fixed to 0x1E (30).
@@ -41,4 +112,6 @@ struct hidi2c_dev_descriptor {
 	__le16 reserved1;
 } __packed;
 
+#define HIDI2C_DEV_DESC_LEN		sizeof(struct hidi2c_dev_descriptor)
+
 #endif /* _HID_OVER_I2C_H_ */