1 files changed, 72 insertions, 0 deletions
diff --git a/include/linux/misc/tsi.h b/include/linux/misc/tsi.h
new file mode 100644
index 000000000000..5273c44688f0
--- /dev/null
+++ b/include/linux/misc/tsi.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * AMD SBTSI shared data structure and auxiliary bus definitions.
+ *
+ * Copyright (C) 2026 Advanced Micro Devices, Inc.
+ */
+
+#ifndef _LINUX_MISC_TSI_H_
+#define _LINUX_MISC_TSI_H_
+
+#include <linux/cleanup.h>
+#include <linux/i2c.h>
+#include <linux/i3c/device.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+/**
+ * struct sbtsi_data - driver private data for an AMD SB-TSI device
+ * @client:	underlying I2C client
+ * @i3cdev:	underlying I3C device (when using I3C bus)
+ * @sbtsi_misc_dev: miscdevice exposing ioctl interface at /dev/sbtsi-<addr>
+ * @lock:           mutex protecting concurrent access to the device
+ * @kref:      reference count; keeps @sbtsi_data alive while misc fds are open
+ * @dev_addr:	I2C/I3C device address, used as the auxiliary device instance id
+ *		and name the misc device node
+ * @ext_range_mode:	sensor uses extended temperature range
+ * @read_order:	if set, decimal part must be read before integer part
+ * @is_i3c:	true when the device is accessed over I3C
+ * @detached:  set on driver unbind; open/ioctl return -ENODEV afterward
+ */
+struct sbtsi_data {
+	union {
+		struct i2c_client *client;
+		struct i3c_device *i3cdev;
+	};
+	struct miscdevice sbtsi_misc_dev;
+	struct mutex lock;	/* protects concurrent access to the device */
+	struct kref kref;
+	u8 dev_addr;
+	bool ext_range_mode;
+	bool read_order;
+	bool is_i3c;
+	bool detached;
+};
+
+DEFINE_GUARD(sbtsi, struct sbtsi_data *, mutex_lock(&_T->lock),
+	     mutex_unlock(&_T->lock))
+
+/*
+ * Name of the auxiliary device published on the auxiliary bus by the core
+ * driver.  The full device name is "amd-sbtsi.temp-sensor.<id>". where
+ * <id> is the auxiliary device instance id.
+ */
+#define AMD_SBTSI_ADEV		"amd-sbtsi"
+#define AMD_SBTSI_AUX_HWMON	"temp-sensor"
+
+/**
+ * sbtsi_xfer - Perform a register read or write transfer on an AMD SB-TSI device.
+ *
+ * @data:    Pointer to the sbtsi_data structure containing the device context
+ * @reg:     Register address to access.
+ * @val:     Pointer to the value to read into or write from.
+ * @is_read: If true, performs a read transfer and stores the result in @val.
+ *           If false, performs a write transfer using the value in @val.
+ *
+ * Returns 0 on success, or a negative error code on failure.
+ */
+int sbtsi_xfer(struct sbtsi_data *data, u8 reg, u8 *val, bool is_read);
+
+#endif /* _LINUX_MISC_TSI_H_ */