[PATCH linux dev-6.6 1/2] hwmon: Add driver for MPS MPQ8785 Synchronous Step-Down Converter
Fred Chen
fredchen.openbmc at gmail.com
Wed Aug 6 22:12:31 AEST 2025
From: Charles Hsu <ythsu0511 at gmail.com>
Add support for mpq8785 device from Monolithic Power Systems, Inc.
(MPS) vendor. This is synchronous step-down controller.
Signed-off-by: Charles Hsu <ythsu0511 at gmail.com>
Link: https://lore.kernel.org/r/20240131074822.2962078-2-ythsu0511@gmail.com
[groeck: probe_new --> probe; add MODULE_IMPORT_NS(PMBUS)]
Signed-off-by: Guenter Roeck <linux at roeck-us.net>
(cherry picked from commit f20b4a931130cb574c40563cfda0fc2cb944b4df)
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/mpq8785.rst | 94 +++++++++++++++++++++++++++++++++
drivers/hwmon/pmbus/Kconfig | 9 ++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/mpq8785.c | 90 +++++++++++++++++++++++++++++++
5 files changed, 195 insertions(+)
create mode 100644 Documentation/hwmon/mpq8785.rst
create mode 100644 drivers/hwmon/pmbus/mpq8785.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 88dadea85cfc..1f9dd8786609 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -158,6 +158,7 @@ Hardware Monitoring Kernel Drivers
mp2888
mp2975
mp5023
+ mpq8785
nct6683
nct6775
nct7802
diff --git a/Documentation/hwmon/mpq8785.rst b/Documentation/hwmon/mpq8785.rst
new file mode 100644
index 000000000000..bf8176b87086
--- /dev/null
+++ b/Documentation/hwmon/mpq8785.rst
@@ -0,0 +1,94 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel driver mpq8785
+=======================
+
+Supported chips:
+
+ * MPS MPQ8785
+
+ Prefix: 'mpq8785'
+
+Author: Charles Hsu <ythsu0511 at gmail.com>
+
+Description
+-----------
+
+The MPQ8785 is a fully integrated, PMBus-compatible, high-frequency, synchronous
+buck converter. The MPQ8785 offers a very compact solution that achieves up to
+40A output current per phase, with excellent load and line regulation over a
+wide input supply range. The MPQ8785 operates at high efficiency over a wide
+output current load range.
+
+The PMBus interface provides converter configurations and key parameters
+monitoring.
+
+The MPQ8785 adopts MPS's proprietary multi-phase digital constant-on-time (MCOT)
+control, which provides fast transient response and eases loop stabilization.
+The MCOT scheme also allows multiple MPQ8785 devices to be connected in parallel
+with excellent current sharing and phase interleaving for high-current
+applications.
+
+Fully integrated protection features include over-current protection (OCP),
+over-voltage protection (OVP), under-voltage protection (UVP), and
+over-temperature protection (OTP).
+
+The MPQ8785 requires a minimal number of readily available, standard external
+components, and is available in a TLGA (5mmx6mm) package.
+
+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_max**
+
+**in1_max_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+**curr1_crit**
+
+**curr1_crit_alarm**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_max**
+
+**temp1_max_alarm**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index b4e93bd5835e..705cf1cc07cc 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -349,6 +349,15 @@ config SENSORS_MPQ7932
This driver can also be built as a module. If so, the module will
be called mpq7932.
+config SENSORS_MPQ8785
+ tristate "MPS MPQ8785"
+ help
+ If you say yes here you get hardware monitoring functionality support
+ for power management IC MPS MPQ8785.
+
+ This driver can also be built as a module. If so, the module will
+ be called mpq8785.
+
config SENSORS_PIM4328
tristate "Flex PIM4328 and compatibles"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 84ee960a6c2d..14f004c26a3f 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_SENSORS_MP2888) += mp2888.o
obj-$(CONFIG_SENSORS_MP2975) += mp2975.o
obj-$(CONFIG_SENSORS_MP5023) += mp5023.o
obj-$(CONFIG_SENSORS_MPQ7932) += mpq7932.o
+obj-$(CONFIG_SENSORS_MPQ8785) += mpq8785.o
obj-$(CONFIG_SENSORS_PLI1209BC) += pli1209bc.o
obj-$(CONFIG_SENSORS_PM6764TR) += pm6764tr.o
obj-$(CONFIG_SENSORS_PXE1610) += pxe1610.o
diff --git a/drivers/hwmon/pmbus/mpq8785.c b/drivers/hwmon/pmbus/mpq8785.c
new file mode 100644
index 000000000000..4e2549cc8120
--- /dev/null
+++ b/drivers/hwmon/pmbus/mpq8785.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MPS MPQ8785 Step-Down Converter
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include "pmbus.h"
+
+static int mpq8785_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;
+ switch (vout_mode >> 5) {
+ case 0:
+ info->format[PSC_VOLTAGE_OUT] = linear;
+ break;
+ case 1:
+ case 2:
+ info->format[PSC_VOLTAGE_OUT] = direct,
+ info->m[PSC_VOLTAGE_OUT] = 64;
+ info->b[PSC_VOLTAGE_OUT] = 0;
+ info->R[PSC_VOLTAGE_OUT] = 1;
+ break;
+ default:
+ return -ENODEV;
+ }
+
+ return 0;
+};
+
+static struct pmbus_driver_info mpq8785_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = direct,
+ .format[PSC_CURRENT_OUT] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_VOLTAGE_IN] = 4,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_CURRENT_OUT] = 16,
+ .b[PSC_CURRENT_OUT] = 0,
+ .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_TEMPERATURE] = 1,
+ .b[PSC_TEMPERATURE] = 0,
+ .R[PSC_TEMPERATURE] = 0,
+ .func[0] =
+ PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
+ PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+ .identify = mpq8785_identify,
+};
+
+static int mpq8785_probe(struct i2c_client *client)
+{
+ return pmbus_do_probe(client, &mpq8785_info);
+};
+
+static const struct i2c_device_id mpq8785_id[] = {
+ { "mpq8785", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, mpq8785_id);
+
+static const struct of_device_id __maybe_unused mpq8785_of_match[] = {
+ { .compatible = "mps,mpq8785" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mpq8785_of_match);
+
+static struct i2c_driver mpq8785_driver = {
+ .driver = {
+ .name = "mpq8785",
+ .of_match_table = of_match_ptr(mpq8785_of_match),
+ },
+ .probe = mpq8785_probe,
+ .id_table = mpq8785_id,
+};
+
+module_i2c_driver(mpq8785_driver);
+
+MODULE_AUTHOR("Charles Hsu <ythsu0511 at gmail.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MPQ8785");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);
--
2.49.0
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