[PATCH v4 2/2] hwmon: (pmbus/tda38740) Add driver for Infineon TDA38740/TDA38725
From: Colin Huang
Date: Thu Sep 10 2026 - 08:37:10 EST
From: Colin Huang <u8813345@xxxxxxxxx>
Add a PMBus driver for Infineon TDA38740 and TDA38725
single-voltage synchronous buck regulators.
Signed-off-by: Colin Huang <u8813345@xxxxxxxxx>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/tda38740.rst | 65 +++++++++++++++++++++++++++
drivers/hwmon/pmbus/Kconfig | 9 ++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/tda38740.c | 94 ++++++++++++++++++++++++++++++++++++++++
5 files changed, 170 insertions(+)
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index f07977a20271..aeff87b3d46d 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -265,6 +265,7 @@ Hardware Monitoring Kernel Drivers
sy7636a-hwmon
tc654
tc74
+ tda38740
thmc50
tmp102
tmp103
diff --git a/Documentation/hwmon/tda38740.rst b/Documentation/hwmon/tda38740.rst
new file mode 100644
index 000000000000..55ce12f14914
--- /dev/null
+++ b/Documentation/hwmon/tda38740.rst
@@ -0,0 +1,65 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+====================================
+Kernel driver tda38740
+====================================
+
+Supported chips:
+ * Infineon TDA38740
+ * Infineon TDA38725
+
+ Prefix: 'tda38740'
+
+ Addresses scanned: -
+
+ Datasheet:
+ https://www.infineon.com/row/public/documents/24/49/infineon-tda38740-tda38725-datasheet-en.pdf
+
+Author: Colin Huang <u8813345@xxxxxxxxx>
+
+Description
+-----------
+
+The TDA38740 and TDA38725 are single-output synchronous buck regulators with a
+PMBus interface. They expose basic voltage, current, power and temperature
+telemetry through the standard PMBus hwmon interfaces.
+
+Sysfs entries
+-------------
+
+======================= =======================================================
+curr1_alarm Input current alarm
+curr1_input Measured input current
+curr1_label "iin"
+
+curr2_crit Critical maximum output current
+curr2_crit_alarm Output current critical high alarm
+curr2_input Measured output current
+curr2_label "iout"
+
+in1_crit Critical maximum input voltage
+in1_crit_alarm Input voltage critical high alarm
+in1_input Measured input voltage
+in1_label "vin"
+
+in2_crit Critical maximum output voltage
+in2_crit_alarm Output voltage critical high alarm
+in2_input Measured output voltage
+in2_label "vout"
+in2_lcrit Critical minimum output voltage
+in2_lcrit_alarm Output voltage critical low alarm
+
+power1_alarm Input power alarm
+power1_input Measured input power
+power1_label "pin"
+
+power2_input Measured output power
+power2_label "pout"
+
+temp1_crit Critical high temperature
+temp1_crit_alarm Chip temperature critical high alarm
+temp1_input Measured temperature
+temp1_max Maximum temperature
+temp1_max_alarm Chip temperature high alarm
+======================= =======================================================
+
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index bcfdc4ce4c10..e4ca80dd0574 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -763,6 +763,15 @@ config SENSORS_TDA38640_REGULATOR
If you say yes here you get regulator support for Infineon
TDA38640 as regulator.
+config SENSORS_TDA38740
+ tristate "Infineon TDA38725/TDA38740"
+ help
+ If you say yes here you get hardware monitoring support for Infineon
+ TDA38725 and TDA38740.
+
+ This driver can also be built as a module. If so, the module will
+ be called tda38740.
+
config SENSORS_TPS25990
tristate "TI TPS25990"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index e288fe72a437..eb06d47816fd 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_SENSORS_STEF48H28) += stef48h28.o
obj-$(CONFIG_SENSORS_SQ24860) += sq24860.o
obj-$(CONFIG_SENSORS_STPDDC60) += stpddc60.o
obj-$(CONFIG_SENSORS_TDA38640) += tda38640.o
+obj-$(CONFIG_SENSORS_TDA38740) += tda38740.o
obj-$(CONFIG_SENSORS_TPS25990) += tps25990.o
obj-$(CONFIG_SENSORS_TPS40422) += tps40422.o
obj-$(CONFIG_SENSORS_TPS53679) += tps53679.o
diff --git a/drivers/hwmon/pmbus/tda38740.c b/drivers/hwmon/pmbus/tda38740.c
new file mode 100644
index 000000000000..6d3e9884f733
--- /dev/null
+++ b/drivers/hwmon/pmbus/tda38740.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for Infineon TDA38725/TDA38740
+ *
+ * Copyright (c) 2023 9elements GmbH
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+/*
+ * TDA38725/TDA38740 only support Linear format for VOUT related commands,
+ * with exponents in the range of -8 to -12 (see datasheet VOUT_MODE
+ * description). Direct format is not supported by this device.
+ */
+static int tda38740_identify(struct i2c_client *client,
+ struct pmbus_driver_info *info)
+{
+ int vout_mode;
+
+ vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
+ if (vout_mode < 0 || vout_mode == 0xff)
+ return vout_mode < 0 ? vout_mode : -ENODEV;
+
+ if ((vout_mode >> 5) != 0)
+ return -ENODEV;
+
+ info->format[PSC_VOLTAGE_OUT] = linear;
+
+ return 0;
+}
+
+static struct pmbus_driver_info tda38740_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = linear,
+ .format[PSC_CURRENT_OUT] = linear,
+ .format[PSC_CURRENT_IN] = linear,
+ .format[PSC_POWER] = linear,
+ .format[PSC_TEMPERATURE] = linear,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+ | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
+ | PMBUS_HAVE_IIN
+ | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+ | PMBUS_HAVE_POUT | PMBUS_HAVE_PIN,
+ .identify = tda38740_identify,
+};
+
+static int tda38740_probe(struct i2c_client *client)
+{
+ struct tda38740_data *data;
+
+ data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ memcpy(&data->info, &tda38740_info, sizeof(tda38740_info));
+
+ return pmbus_do_probe(client, &data->info);
+}
+
+static const struct i2c_device_id tda38740_id[] = {
+ { .name = "tda38725"},
+ { .name = "tda38740"},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, tda38740_id);
+
+static const struct of_device_id __maybe_unused tda38740_of_match[] = {
+ { .compatible = "infineon,tda38725"},
+ { .compatible = "infineon,tda38740"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, tda38740_of_match);
+
+static struct i2c_driver tda38740_driver = {
+ .driver = {
+ .name = "tda38740",
+ .of_match_table = of_match_ptr(tda38740_of_match),
+ },
+ .probe = tda38740_probe,
+ .id_table = tda38740_id,
+};
+
+module_i2c_driver(tda38740_driver);
+
+MODULE_DESCRIPTION("PMBus driver for Infineon TDA38725/TDA38740");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.34.1