[PATCH v2 3/6] hwmon/misc: amd-sbi: Move sbtsi register transfer to core abstraction

[Akshay Gupta <Akshay.Gupta@amd.com>]

From: Prathima <Prathima.Lk@amd.com>

Move the I2C read/write byte operations from the sbtsi hwmon driver into
a common sbtsi_xfer() function in tsi-core.c.
This decouples the hwmon sensor driver from the underlying bus transport,
preparing for I3C support in a subsequent patch.
This patch does not introduce any functional changes. The updates are limited
to code organization/cleanup and should not affect the runtime
behavior of the driver

Reviewed-by: Akshay Gupta <Akshay.Gupta@amd.com>
Signed-off-by: Prathima <Prathima.Lk@amd.com>
---
Changes since v1:
- New patch

 drivers/hwmon/sbtsi_temp.c      | 17 ++++++-----------
 drivers/misc/amd-sbi/Makefile   |  2 +-
 drivers/misc/amd-sbi/tsi-core.c | 30 ++++++++++++++++++++++++++++++
 include/linux/misc/tsi.h        | 13 +++++++++++++
 4 files changed, 50 insertions(+), 12 deletions(-)
 create mode 100644 drivers/misc/amd-sbi/tsi-core.c

diff --git a/drivers/hwmon/sbtsi_temp.c b/drivers/hwmon/sbtsi_temp.c
index 078f4ab25bde..d7ae986d824c 100644
--- a/drivers/hwmon/sbtsi_temp.c
+++ b/drivers/hwmon/sbtsi_temp.c
@@ -70,15 +70,10 @@ static int sbtsi_temp_read(struct sbtsi_data *data, u8 reg1, u8 reg2,
 {
 	int ret;
 
-	ret = i2c_smbus_read_byte_data(data->client, reg1);
-	if (ret < 0)
-		return ret;
-	*val1 = ret;
-	ret = i2c_smbus_read_byte_data(data->client, reg2);
-	if (ret < 0)
-		return ret;
-	*val2 = ret;
-	return 0;
+	ret = sbtsi_xfer(data, reg1, val1, true);
+	if (!ret)
+		ret = sbtsi_xfer(data, reg2, val2, true);
+	return ret;
 }
 
 /*
@@ -89,9 +84,9 @@ static int sbtsi_temp_write(struct sbtsi_data *data, u8 reg_int, u8 reg_dec,
 {
 	int ret;
 
-	ret = i2c_smbus_write_byte_data(data->client, reg_int, val_int);
+	ret = sbtsi_xfer(data, reg_int, &val_int, false);
 	if (!ret)
-		ret = i2c_smbus_write_byte_data(data->client, reg_dec, val_dec);
+		ret = sbtsi_xfer(data, reg_dec, &val_dec, false);
 	return ret;
 }
 
diff --git a/drivers/misc/amd-sbi/Makefile b/drivers/misc/amd-sbi/Makefile
index 28f95b9e204f..ce9321f5c601 100644
--- a/drivers/misc/amd-sbi/Makefile
+++ b/drivers/misc/amd-sbi/Makefile
@@ -3,5 +3,5 @@ sbrmi-i2c-objs  		+= rmi-i2c.o rmi-core.o
 sbrmi-i2c-$(CONFIG_AMD_SBRMI_HWMON)	+= rmi-hwmon.o
 obj-$(CONFIG_AMD_SBRMI_I2C)	+= sbrmi-i2c.o
 # SBTSI Configuration
-sbtsi-objs	+= tsi.o
+sbtsi-objs	+= tsi.o tsi-core.o
 obj-$(CONFIG_AMD_SBTSI)	+= sbtsi.o
diff --git a/drivers/misc/amd-sbi/tsi-core.c b/drivers/misc/amd-sbi/tsi-core.c
new file mode 100644
index 000000000000..6ef1831515bb
--- /dev/null
+++ b/drivers/misc/amd-sbi/tsi-core.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * tsi-core.c - file defining SB-TSI protocols compliant
+ *              AMD SoC device.
+ *
+ * Copyright (C) 2026 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/misc/tsi.h>
+
+/* I2C transfer function */
+static int sbtsi_i2c_xfer(struct sbtsi_data *data, u8 reg, u8 *val, bool is_read)
+{
+	if (is_read) {
+		int ret = i2c_smbus_read_byte_data(data->client, reg);
+
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return 0;
+	}
+	return i2c_smbus_write_byte_data(data->client, reg, *val);
+}
+
+int sbtsi_xfer(struct sbtsi_data *data, u8 reg, u8 *val, bool is_read)
+{
+	return sbtsi_i2c_xfer(data, reg, val, is_read);
+}
+EXPORT_SYMBOL_GPL(sbtsi_xfer);
diff --git a/include/linux/misc/tsi.h b/include/linux/misc/tsi.h
index 6f7177edbcf5..8f8cb90c2023 100644
--- a/include/linux/misc/tsi.h
+++ b/include/linux/misc/tsi.h
@@ -31,4 +31,17 @@ struct sbtsi_data {
 #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_TSI_H_ */
-- 
2.34.1