hwmon: (pmbus/d1u74t) Add Murata D1U74T PSU driver

Add PMBUS driver for Murata D1U74T power supplies.

Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Link: https://lore.kernel.org/r/20260514-d1u74t-v4-2-1f1ee7b002ec@nexthop.ai
[groeck: Dropped inappropriate tags; added missing include files]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

3 files changed, 98 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index c3bb6df2655a..64f38654f4e7 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -113,6 +113,15 @@ config SENSORS_CRPS
 	  This driver can also be built as a module. If so, the module will
 	  be called crps.
 
+config SENSORS_D1U74T
+	tristate "Murata D1U74T Power Supply"
+	help
+	  If you say yes here you get hardware monitoring support for the Murata
+	  D1U74T Power Supply.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called d1u74t.
+
 config SENSORS_DELTA_AHE50DC_FAN
 	tristate "Delta AHE-50DC fan control module"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index efd70b00ca2e..1f2c73b71953 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -80,3 +80,4 @@ obj-$(CONFIG_SENSORS_XDPE1A2G7B)	+= xdpe1a2g7b.o
 obj-$(CONFIG_SENSORS_ZL6100)	+= zl6100.o
 obj-$(CONFIG_SENSORS_PIM4328)	+= pim4328.o
 obj-$(CONFIG_SENSORS_CRPS)	+= crps.o
+obj-$(CONFIG_SENSORS_D1U74T)	+= d1u74t.o
diff --git a/drivers/hwmon/pmbus/d1u74t.c b/drivers/hwmon/pmbus/d1u74t.c
new file mode 100644
index 000000000000..752df3af9c1a
--- /dev/null
+++ b/drivers/hwmon/pmbus/d1u74t.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2026 Nexthop Systems.
+ */
+
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include <linux/string.h>
+
+#include "pmbus.h"
+
+static const struct i2c_device_id d1u74t_id[] = {
+	{ "d1u74t" },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, d1u74t_id);
+
+static struct pmbus_driver_info d1u74t_info = {
+	.pages = 1,
+	/* PSU uses default linear data format. */
+	.func[0] = PMBUS_HAVE_PIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		   PMBUS_HAVE_IIN | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
+		   PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_TEMP |
+		   PMBUS_HAVE_TEMP2 | PMBUS_HAVE_TEMP3 |
+		   PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_FAN12 |
+		   PMBUS_HAVE_STATUS_FAN12,
+};
+
+static int d1u74t_probe(struct i2c_client *client)
+{
+	char buf[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };
+	struct device *dev = &client->dev;
+	int rc;
+
+	rc = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+	if (rc < 0)
+		return dev_err_probe(dev, rc, "Failed to read PMBUS_MFR_ID\n");
+
+	if (rc != 9 || strncmp(buf, "Murata-PS", 9)) {
+		buf[rc] = '\0';
+		return dev_err_probe(dev, -ENODEV,
+				     "Unsupported Manufacturer ID '%s'\n",
+				     buf);
+	}
+
+	rc = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+	if (rc < 0)
+		return dev_err_probe(dev, rc,
+				     "Failed to read PMBUS_MFR_MODEL\n");
+
+	if (rc < 8 || strncmp(buf, "D1U74T-W", 8)) {
+		buf[rc] = '\0';
+		return dev_err_probe(dev, -ENODEV, "Model '%s' not supported\n",
+				     buf);
+	}
+
+	rc = pmbus_do_probe(client, &d1u74t_info);
+	if (rc)
+		return dev_err_probe(dev, rc, "Failed to probe\n");
+
+	return 0;
+}
+
+static const struct of_device_id d1u74t_of_match[] = {
+	{
+		.compatible = "murata,d1u74t",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, d1u74t_of_match);
+
+static struct i2c_driver d1u74t_driver = {
+	.driver = {
+		.name = "d1u74t",
+		.of_match_table = d1u74t_of_match,
+	},
+	.probe = d1u74t_probe,
+	.id_table = d1u74t_id,
+};
+
+module_i2c_driver(d1u74t_driver);
+
+MODULE_AUTHOR("Abdurrahman Hussain");
+MODULE_DESCRIPTION("PMBus driver for Murata D1U74T-W power supplies");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");