* [PATCH v6 2/2] hwmon: pmbus: add support for STEF48H28
2026-01-16 8:58 [PATCH v6 1/2] dt-bindings: hwmon: add STEF48H28 Charles Hsu
@ 2026-01-16 8:58 ` Charles Hsu
2026-01-16 9:19 ` [PATCH v6 1/2] dt-bindings: hwmon: add STEF48H28 Krzysztof Kozlowski
1 sibling, 0 replies; 3+ messages in thread
From: Charles Hsu @ 2026-01-16 8:58 UTC (permalink / raw)
To: linux, robh, krzk+dt, conor+dt, corbet
Cc: linux-hwmon, devicetree, linux-kernel, linux-doc, Charles Hsu
Add support for STEF48H28 hot-swap controller.
Signed-off-by: Charles Hsu <hsu.yungteng@gmail.com>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/stef48h28.rst | 73 ++++++++++++++++++++++++++++++
MAINTAINERS | 7 +++
drivers/hwmon/pmbus/Kconfig | 9 ++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/stef48h28.c | 75 +++++++++++++++++++++++++++++++
6 files changed, 166 insertions(+)
create mode 100644 Documentation/hwmon/stef48h28.rst
create mode 100644 drivers/hwmon/pmbus/stef48h28.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 85d7a686883e..c682751a1fe3 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -233,6 +233,7 @@ Hardware Monitoring Kernel Drivers
shtc1
sis5595
sl28cpld
+ stef48h28
smpro-hwmon
smsc47b397
smsc47m192
diff --git a/Documentation/hwmon/stef48h28.rst b/Documentation/hwmon/stef48h28.rst
new file mode 100644
index 000000000000..00bef9e55651
--- /dev/null
+++ b/Documentation/hwmon/stef48h28.rst
@@ -0,0 +1,73 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver stef48h28
+=======================
+
+Supported chips:
+
+ * Analog Devices STEF48H28
+
+ Prefix: 'stef48h28'
+
+ Addresses scanned: -
+
+ Datasheet: https://www.st.com/resource/en/data_brief/stef48h28.pdf
+
+Author:
+
+ - Charles Hsu <hsu.yungteng@gmail.com>
+
+
+Description
+-----------
+
+The STEF48H28 is a 30 A integrated e-fuse for 9-80 V DC power rails.
+It provides inrush control, undervoltage/overvoltage lockout and
+overcurrent protection using an adaptive (I x t) scheme that permits
+short high-current pulses typical of CPU/GPU loads.
+
+The device offers an analog current-monitor output and an on-chip
+temperature-monitor signal for system supervision. Startup behavior is
+programmable through insertion-delay and soft-start settings.
+
+Additional features include power-good indication, self-diagnostics,
+thermal shutdown and a PMBus interface for telemetry and status
+reporting.
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+Sysfs entries
+-------------
+
+=========================================================
+in1_label "vin".
+in1_input Measured voltage. From READ_VIN register.
+in1_min Minimum Voltage. From VIN_UV_WARN_LIMIT register.
+in1_max Maximum voltage. From VIN_OV_WARN_LIMIT register.
+
+in2_label "vout1".
+in2_input Measured voltage. From READ_VOUT register.
+in2_min Minimum Voltage. From VOUT_UV_WARN_LIMIT register.
+in2_max Maximum voltage. From VOUT_OV_WARN_LIMIT register.
+
+curr1_label "iin".
+curr1_input Measured current. From READ_IIN register.
+
+curr2_label "iout1".
+curr2_input Measured current. From READ_IOUT register.
+
+power1_label "pin"
+power1_input Measured input power. From READ_PIN register.
+
+power2_label "pout1"
+power2_input Measured output power. From READ_POUT register.
+
+temp1_input Measured temperature. From READ_TEMPERATURE_1 register.
+temp1_max Maximum temperature. From OT_WARN_LIMIT register.
+temp1_crit Critical high temperature. From OT_FAULT_LIMIT register.
+
+temp2_input Measured temperature. From READ_TEMPERATURE_2 register.
+=========================================================
diff --git a/MAINTAINERS b/MAINTAINERS
index d701a4d5b00e..be6b6e9ee79b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -24665,6 +24665,13 @@ S: Maintained
F: Documentation/devicetree/bindings/power/supply/st,stc3117.yaml
F: drivers/power/supply/stc3117_fuel_gauge.c
+ST STEF48H28 DRIVER
+M: Charles Hsu <hsu.yungteng@gmail.com>
+L: linux-hwmon@vger.kernel.org
+S: Maintained
+F: Documentation/hwmon/stef48h28.rst
+F: drivers/hwmon/pmbus/stef48h28.c
+
ST STM32 FIREWALL
M: Gatien Chevallier <gatien.chevallier@foss.st.com>
S: Maintained
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index f3fb94cebf1a..29ea8ba98b8b 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -576,6 +576,15 @@ config SENSORS_Q54SJ108A2
This driver can also be built as a module. If so, the module will
be called q54sj108a2.
+config SENSORS_STEF48H28
+ tristate "ST STEF48H28"
+ help
+ If you say yes here you get hardware monitoring support for ST
+ STEF48H28.
+
+ This driver can also be built as a module. If so, the module will
+ be called stef48h28.
+
config SENSORS_STPDDC60
tristate "ST STPDDC60"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 349a89b6d92e..b2497f1d7bd9 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_SENSORS_PLI1209BC) += pli1209bc.o
obj-$(CONFIG_SENSORS_PM6764TR) += pm6764tr.o
obj-$(CONFIG_SENSORS_PXE1610) += pxe1610.o
obj-$(CONFIG_SENSORS_Q54SJ108A2) += q54sj108a2.o
+obj-$(CONFIG_SENSORS_STEF48H28) += stef48h28.o
obj-$(CONFIG_SENSORS_STPDDC60) += stpddc60.o
obj-$(CONFIG_SENSORS_TDA38640) += tda38640.o
obj-$(CONFIG_SENSORS_TPS25990) += tps25990.o
diff --git a/drivers/hwmon/pmbus/stef48h28.c b/drivers/hwmon/pmbus/stef48h28.c
new file mode 100644
index 000000000000..4bde2215697c
--- /dev/null
+++ b/drivers/hwmon/pmbus/stef48h28.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for STMicroelectronics digital controller stef48h28
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+
+#include "pmbus.h"
+
+static struct pmbus_driver_info stef48h28_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = direct,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_CURRENT_IN] = direct,
+ .format[PSC_CURRENT_OUT] = direct,
+ .format[PSC_POWER] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_VOLTAGE_IN] = 50,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = 0,
+ .m[PSC_VOLTAGE_OUT] = 50,
+ .b[PSC_VOLTAGE_OUT] = 0,
+ .R[PSC_VOLTAGE_OUT] = 0,
+ .m[PSC_CURRENT_IN] = 100,
+ .b[PSC_CURRENT_IN] = 0,
+ .R[PSC_CURRENT_IN] = 0,
+ .m[PSC_CURRENT_OUT] = 100,
+ .b[PSC_CURRENT_OUT] = 0,
+ .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_POWER] = 9765,
+ .b[PSC_POWER] = 0,
+ .R[PSC_POWER] = -3,
+ .m[PSC_TEMPERATURE] = 25,
+ .b[PSC_TEMPERATURE] = 500,
+ .R[PSC_TEMPERATURE] = 0,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN
+ | PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
+ | PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_POUT
+};
+
+static int stef48h28_probe(struct i2c_client *client)
+{
+ return pmbus_do_probe(client, &stef48h28_info);
+}
+
+static const struct i2c_device_id stef48h28_id[] = {
+ {"stef48h28"},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, stef48h28_id);
+
+static const struct of_device_id __maybe_unused stef48h28_of_match[] = {
+ {.compatible = "st,stef48h28"},
+ {}
+};
+
+static struct i2c_driver stef48h28_driver = {
+ .driver = {
+ .name = "stef48h28",
+ .of_match_table = of_match_ptr(stef48h28_of_match),
+ },
+ .probe = stef48h28_probe,
+ .id_table = stef48h28_id,
+};
+
+module_i2c_driver(stef48h28_driver);
+
+MODULE_AUTHOR("Charles Hsu <hsu.yungteng@gmail.com>");
+MODULE_DESCRIPTION("PMBus driver for ST stef48h28");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.34.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v6 1/2] dt-bindings: hwmon: add STEF48H28
2026-01-16 8:58 [PATCH v6 1/2] dt-bindings: hwmon: add STEF48H28 Charles Hsu
2026-01-16 8:58 ` [PATCH v6 2/2] hwmon: pmbus: add support for STEF48H28 Charles Hsu
@ 2026-01-16 9:19 ` Krzysztof Kozlowski
1 sibling, 0 replies; 3+ messages in thread
From: Krzysztof Kozlowski @ 2026-01-16 9:19 UTC (permalink / raw)
To: Charles Hsu, linux, robh, krzk+dt, conor+dt, corbet
Cc: linux-hwmon, devicetree, linux-kernel, linux-doc
On 16/01/2026 09:58, Charles Hsu wrote:
> +properties:
> + compatible:
> + enum:
> + - st,stef48h28
> +
> + reg:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> +
> +unevaluatedProperties: false
This must be additionalProperties instead, see speeches/presentations
material or very explicit rule in writing bindings.
OTOH, this is so trivial now, that you could just add it to
trivial-devices schema.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 3+ messages in thread