* [PATCH v4 2/2] hwmon: add mp5926 driver
2025-12-23 1:22 [PATCH v4 0/2] hwmon: Add support for MPS mp5926 chip Yuxi Wang
2025-12-23 1:22 ` [PATCH v4 1/2] dt-bindings: hwmon: Add mps mp5926 driver bindings Yuxi Wang
@ 2025-12-23 1:22 ` Yuxi Wang
1 sibling, 0 replies; 4+ messages in thread
From: Yuxi Wang @ 2025-12-23 1:22 UTC (permalink / raw)
To: Yuxi.Wang, linux, corbet, robh, krzk+dt, conor+dt
Cc: wyx137120466, linux-hwmon, linux-doc, linux-kernel, devicetree
Add support for mps mp5926.
Signed-off-by: Yuxi Wang <Yuxi.Wang@monolithicpower.com>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/mp5926.rst | 92 +++++++++++++++++
MAINTAINERS | 7 ++
drivers/hwmon/pmbus/Kconfig | 9 ++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/mp5926.c | 183 +++++++++++++++++++++++++++++++++
6 files changed, 293 insertions(+)
create mode 100644 Documentation/hwmon/mp5926.rst
create mode 100644 drivers/hwmon/pmbus/mp5926.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 85d7a686883e..6181c3f62177 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -185,6 +185,7 @@ Hardware Monitoring Kernel Drivers
mp2993
mp5023
mp5920
+ mp5926
mp5990
mp9941
mp9945
diff --git a/Documentation/hwmon/mp5926.rst b/Documentation/hwmon/mp5926.rst
new file mode 100644
index 000000000000..4b64a7e24ae6
--- /dev/null
+++ b/Documentation/hwmon/mp5926.rst
@@ -0,0 +1,92 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp5926
+====================
+
+Supported chips:
+
+ * MPS mp5926
+
+ Prefix: 'mp5926'
+
+ * Datasheet
+ https://www.monolithicpower.com/en/
+
+Author:
+
+ Yuxi Wang <Yuxi.Wang@monolithicpower.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MP5926 Hot-Swap Controller.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_lcrit**
+
+**in2_lcrit_alarm**
+
+**in2_rated_max**
+
+**in2_rated_min**
+
+The driver provides the following attributes for input current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr2_input**
+
+**curr2_label**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+The driver provides the following attributes for output power:
+
+**power2_input**
+
+**power2_label**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
+
+**temp1_max**
+
+**temp1_max_alarm**
diff --git a/MAINTAINERS b/MAINTAINERS
index d701a4d5b00e..fea710aab535 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17708,6 +17708,13 @@ S: Maintained
F: Documentation/hwmon/mp2993.rst
F: drivers/hwmon/pmbus/mp2993.c
+MPS MP5926 DRIVER
+M: Yuxi Wang <Yuxi.Wang@monolithicpower.com>
+L: linux-hwmon@vger.kernel.org
+S: Maintained
+F: Documentation/hwmon/mp5926.rst
+F: drivers/hwmon/pmbus/mp5926.c
+
MPS MP9941 DRIVER
M: Noah Wang <noahwang.wang@outlook.com>
L: linux-hwmon@vger.kernel.org
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index f3fb94cebf1a..d0aa460abdc9 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -472,6 +472,15 @@ config SENSORS_MP5920
This driver can also be built as a module. If so, the module will
be called mp5920.
+config SENSORS_MP5926
+ tristate "MPS MP5926"
+ help
+ If you say yes here you get hardware monitoring support for Monolithic
+ MP5926.
+
+ This driver can also be built as a module. If so, the module will
+ be called mp5926.
+
config SENSORS_MP5990
tristate "MPS MP5990"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 349a89b6d92e..75ec4956ca8d 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_SENSORS_MP2975) += mp2975.o
obj-$(CONFIG_SENSORS_MP2993) += mp2993.o
obj-$(CONFIG_SENSORS_MP5023) += mp5023.o
obj-$(CONFIG_SENSORS_MP5920) += mp5920.o
+obj-$(CONFIG_SENSORS_MP5926) += mp5926.o
obj-$(CONFIG_SENSORS_MP5990) += mp5990.o
obj-$(CONFIG_SENSORS_MP9941) += mp9941.o
obj-$(CONFIG_SENSORS_MP9945) += mp9945.o
diff --git a/drivers/hwmon/pmbus/mp5926.c b/drivers/hwmon/pmbus/mp5926.c
new file mode 100644
index 000000000000..f7671eae5a48
--- /dev/null
+++ b/drivers/hwmon/pmbus/mp5926.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// mp5926.c - pmbus driver for mps mp5926
+//
+// Copyright 2025 Monolithic Power Systems, Inc
+//
+// Author: Yuxi Wang <Yuxi.Wang@monolithicpower.com>
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+#define PAGE 0x01
+#define EFUSE_CFG 0xCF
+#define I_SCALE_SEL 0xC6
+#define MP5926_FUNC (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
+ PMBUS_HAVE_IIN | PMBUS_HAVE_PIN | \
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_INPUT | \
+ PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_VOUT)
+
+struct mp5926_data {
+ struct pmbus_driver_info info;
+ u8 vout_mode;
+ u8 vout_linear_exponent;
+};
+
+#define to_mp5926_data(x) container_of(x, struct mp5926_data, info)
+
+static int mp5926_read_byte_data(struct i2c_client *client, int page,
+ int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct mp5926_data *data = to_mp5926_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_VOUT_MODE:
+ if (data->vout_mode == linear) {
+ /*
+ * The VOUT format used by the chip is linear11,
+ * not linear16. Report that VOUT is in linear mode
+ * and return exponent value extracted while probing
+ * the chip.
+ */
+ return data->vout_linear_exponent;
+ }
+ return PB_VOUT_MODE_DIRECT;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
+static int mp5926_read_word_data(struct i2c_client *client, int page, int phase,
+ int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct mp5926_data *data = to_mp5926_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_READ_VOUT:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+ /*
+ * Because the VOUT format used by the chip is linear11 and not
+ * linear16, we disregard bits[15:11]. The exponent is reported
+ * as part of the VOUT_MODE command.
+ */
+ if (data->vout_mode == linear)
+ ret = ((s16)((ret & 0x7ff) << 5)) >> 5;
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
+static struct pmbus_driver_info mp5926_info = {
+ .pages = PAGE,
+ .format[PSC_VOLTAGE_IN] = direct,
+ .format[PSC_CURRENT_IN] = direct,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .format[PSC_POWER] = direct,
+
+ .m[PSC_VOLTAGE_IN] = 16,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = 0,
+
+ .m[PSC_CURRENT_IN] = 16,
+ .b[PSC_CURRENT_IN] = 0,
+ .R[PSC_CURRENT_IN] = 0,
+
+ .m[PSC_VOLTAGE_OUT] = 16,
+ .b[PSC_VOLTAGE_OUT] = 0,
+ .R[PSC_VOLTAGE_OUT] = 0,
+
+ .m[PSC_TEMPERATURE] = 4,
+ .b[PSC_TEMPERATURE] = 0,
+ .R[PSC_TEMPERATURE] = 0,
+
+ .m[PSC_POWER] = 25,
+ .b[PSC_POWER] = 0,
+ .R[PSC_POWER] = -2,
+
+ .read_word_data = mp5926_read_word_data,
+ .read_byte_data = mp5926_read_byte_data,
+ .func[0] = MP5926_FUNC,
+};
+
+static int mp5926_probe(struct i2c_client *client)
+{
+ struct mp5926_data *data;
+ struct pmbus_driver_info *info;
+ int ret;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct mp5926_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ memcpy(&data->info, &mp5926_info, sizeof(*info));
+ info = &data->info;
+ ret = i2c_smbus_read_word_data(client, EFUSE_CFG);
+ if (ret < 0)
+ return ret;
+ if (ret & BIT(12)) {
+ data->vout_mode = linear;
+ data->info.format[PSC_VOLTAGE_IN] = linear;
+ data->info.format[PSC_CURRENT_IN] = linear;
+ data->info.format[PSC_VOLTAGE_OUT] = linear;
+ data->info.format[PSC_TEMPERATURE] = linear;
+ data->info.format[PSC_POWER] = linear;
+ ret = i2c_smbus_read_word_data(client, PMBUS_READ_VOUT);
+ if (ret < 0)
+ return dev_err_probe(&client->dev, ret, "Can't get vout exponent.");
+ data->vout_linear_exponent = (u8)((ret >> 11) & 0x1f);
+ } else {
+ data->vout_mode = direct;
+ ret = i2c_smbus_read_word_data(client, I_SCALE_SEL);
+ if (ret < 0)
+ return ret;
+ if (ret & BIT(6))
+ data->info.m[PSC_CURRENT_IN] = 4;
+ }
+
+ return pmbus_do_probe(client, info);
+}
+
+static const struct i2c_device_id mp5926_id[] = {
+ { "mp5926", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, mp5926_id);
+
+static const struct of_device_id mp5926_of_match[] = {
+ { .compatible = "mps,mp5926" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mp5926_of_match);
+
+static struct i2c_driver mp5926_driver = {
+ .probe = mp5926_probe,
+ .driver = {
+ .name = "mp5926",
+ .of_match_table = mp5926_of_match,
+ },
+ .id_table = mp5926_id,
+};
+
+module_i2c_driver(mp5926_driver);
+MODULE_AUTHOR("Yuxi Wang <Yuxi.Wang@monolithicpower.com>");
+MODULE_DESCRIPTION("MPS MP5926 pmbus driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.39.2
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