hwmon: pmbus: add support for STEF48H28

Add support for STEF48H28 hot-swap controller.

Signed-off-by: Charles Hsu <hsu.yungteng@gmail.com>
Link: https://lore.kernel.org/r/20260126063712.1049025-2-hsu.yungteng@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -234,6 +234,7 @@ Hardware Monitoring Kernel Drivers
    shtc1
    sis5595
    sl28cpld
+   stef48h28
    smpro-hwmon
    smsc47b397
    smsc47m192

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.
+=========================================================

MAINTAINERS

@@ -24710,6 +24710,13 @@ 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

drivers/hwmon/pmbus/Kconfig

@@ -585,6 +585,15 @@ 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

drivers/hwmon/pmbus/Makefile

@@ -57,6 +57,7 @@ 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

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");