[PATCH v4 0/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

[PATCH v4 0/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

[Pradhan, Sanman]

From: Sanman Pradhan <psanman@juniper.net>

Add PMBus hwmon driver and DT binding for the Analog Devices MAX20860A
step-down DC-DC switching regulator. The driver provides monitoring of
input/output voltage, output current, and temperature using linear data
format. Optional regulator support is available via Kconfig.

The driver does not modify device write-protection state during probe and
relies on the PMBus core to handle write-protect detection and sysfs
attribute permissions.

Tested on PTX platform with MAX20860A at i2c-195/0x23:
  - All sensors (vin, vout, iout, temp1, temp2) read correctly
  - Limit attributes correctly read-only (HW write-protect honored)
  - Clean dmesg (no probe errors)

Changes since v3:
  - Driver: Added optional regulator support via
    CONFIG_SENSORS_MAX20860A_REGULATOR

Changes since v2:
  - DT binding: Drop "maxim,max20860a" and keep only "adi,max20860a"
  - Driver: Drop matching "maxim,max20860a" OF match entry

Changes since v1:
  - DT binding: Added allOf regulator.yaml reference and unevaluatedProperties
  - Driver: Removed WRITE_PROTECT write from probe

Sanman Pradhan (1):
  dt-bindings: hwmon: pmbus: Add Analog Devices MAX20860A

Syed Arif (1):
  hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

 .../bindings/hwmon/pmbus/adi,max20860a.yaml   | 45 ++++++++++++
 Documentation/hwmon/index.rst                 |  1 +
 Documentation/hwmon/max20860a.rst             | 57 ++++++++++++++++
 MAINTAINERS                                   |  8 +++
 drivers/hwmon/pmbus/Kconfig                   | 19 ++++++
 drivers/hwmon/pmbus/Makefile                  |  1 +
 drivers/hwmon/pmbus/max20860a.c               | 68 +++++++++++++++++++
 7 files changed, 199 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
 create mode 100644 Documentation/hwmon/max20860a.rst
 create mode 100644 drivers/hwmon/pmbus/max20860a.c

-- 
2.34.1

[PATCH v4 1/2] dt-bindings: hwmon: pmbus: Add Analog Devices MAX20860A

[Pradhan, Sanman]

From: Sanman Pradhan <psanman@juniper.net>

Add devicetree binding documentation for the Analog Devices MAX20860A
step-down DC-DC switching regulator with PMBus interface.

Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
Changes since v3:
  - No change
Changes since v2:
  - Drop "maxim,max20860a"; use const: adi,max20860a
Changes since v1:
  - Added allOf regulator.yaml reference and unevaluatedProperties

 .../bindings/hwmon/pmbus/adi,max20860a.yaml   | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml

diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
new file mode 100644
index 000000000000..dd238265d462
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/pmbus/adi,max20860a.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices MAX20860A Step-Down Converter
+
+maintainers:
+  - Sanman Pradhan <psanman@juniper.net>
+
+description: |
+  The MAX20860A is a fully integrated step-down DC-DC switching regulator
+  with PMBus interface for monitoring input/output voltage, output current
+  and temperature.
+
+  Datasheet: https://www.analog.com/en/products/max20860a.html
+
+allOf:
+  - $ref: /schemas/regulator/regulator.yaml#
+
+properties:
+  compatible:
+    const: adi,max20860a
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        regulator@40 {
+            compatible = "adi,max20860a";
+            reg = <0x40>;
+        };
+    };
-- 
2.34.1

[PATCH v4 2/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

[Pradhan, Sanman]

From: Syed Arif <arif.syed@hpe.com>

Add a PMBus driver for the Analog Devices MAX20860A step-down DC-DC
switching regulator. The MAX20860A provides monitoring of input/output
voltage, output current, and temperature via the PMBus interface using
linear data format. Optional regulator support is available via
CONFIG_SENSORS_MAX20860A_REGULATOR.

Signed-off-by: Syed Arif <arif.syed@hpe.com>
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
---
Changes since v3:
  - Added optional regulator support via CONFIG_SENSORS_MAX20860A_REGULATOR
Changes since v2:
  - Drop "maxim,max20860a" OF match entry
Changes since v1:
  - Removed WRITE_PROTECT write from probe

 Documentation/hwmon/index.rst     |  1 +
 Documentation/hwmon/max20860a.rst | 57 ++++++++++++++++++++++++++
 MAINTAINERS                       |  8 ++++
 drivers/hwmon/pmbus/Kconfig       | 19 +++++++++
 drivers/hwmon/pmbus/Makefile      |  1 +
 drivers/hwmon/pmbus/max20860a.c   | 68 +++++++++++++++++++++++++++++++
 6 files changed, 154 insertions(+)
 create mode 100644 Documentation/hwmon/max20860a.rst
 create mode 100644 drivers/hwmon/pmbus/max20860a.c

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index e880c6ca84f0..ffaacda416e7 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -163,6 +163,7 @@ Hardware Monitoring Kernel Drivers
    max20730
    max20751
    max20830
+   max20860a
    max31722
    max31730
    max31760
diff --git a/Documentation/hwmon/max20860a.rst b/Documentation/hwmon/max20860a.rst
new file mode 100644
index 000000000000..ea6d2228fafc
--- /dev/null
+++ b/Documentation/hwmon/max20860a.rst
@@ -0,0 +1,57 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver max20860a
+=======================
+
+Supported chips:
+
+  * Analog Devices MAX20860A
+
+    Prefix: 'max20860a'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/en/products/max20860a.html
+
+Author:
+
+  - Syed Arif <arif.syed@hpe.com>
+  - Sanman Pradhan <psanman@juniper.net>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices MAX20860A
+Step-Down Switching Regulator with PMBus Interface.
+
+The MAX20860A is a fully integrated step-down DC-DC switching regulator.
+Through the PMBus interface, the device can monitor input/output voltages,
+output current and temperature.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate
+the devices explicitly.
+
+Sysfs entries
+-------------
+
+================= ========================================
+in1_label         "vin"
+in1_input         Measured input voltage
+in1_alarm         Input voltage alarm
+in2_label         "vout1"
+in2_input         Measured output voltage
+in2_alarm         Output voltage alarm
+curr1_label       "iout1"
+curr1_input       Measured output current
+curr1_alarm       Output current alarm
+temp1_input       Measured temperature
+temp1_alarm       Chip temperature alarm
+temp2_input       Measured temperature (secondary)
+================= ========================================
diff --git a/MAINTAINERS b/MAINTAINERS
index b71acb130395..1d9651947ee3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15688,6 +15688,14 @@ F:	Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml
 F:	Documentation/hwmon/max20830.rst
 F:	drivers/hwmon/pmbus/max20830.c
 
+MAX20860A HARDWARE MONITOR DRIVER
+M:	Sanman Pradhan <psanman@juniper.net>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/hwmon/pmbus/adi,max20860a.yaml
+F:	Documentation/hwmon/max20860a.rst
+F:	drivers/hwmon/pmbus/max20860a.c
+
 MAX2175 SDR TUNER DRIVER
 M:	Ramesh Shanmugasundaram <rashanmu@gmail.com>
 L:	linux-media@vger.kernel.org
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 64f38654f4e7..f330dc3f21fe 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -402,6 +402,25 @@ config SENSORS_MAX20830
 	  This driver can also be built as a module. If so, the module will
 	  be called max20830.
 
+config SENSORS_MAX20860A
+	tristate "Analog Devices MAX20860A"
+	help
+	  If you say yes here you get hardware monitoring support for Analog
+	  Devices MAX20860A step-down converter.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called max20860a.
+
+config SENSORS_MAX20860A_REGULATOR
+	bool "Regulator support for MAX20860A"
+	depends on SENSORS_MAX20860A && REGULATOR
+	help
+	  If you say yes here you get regulator support for Analog Devices
+	  MAX20860A step-down converter.
+
+	  This enables the MAX20860A to be used as a regulator device,
+	  providing voltage control through the regulator framework.
+
 config SENSORS_MAX31785
 	tristate "Maxim MAX31785 and compatibles"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 1f2c73b71953..ffc05f493213 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_SENSORS_MAX17616)	+= max17616.o
 obj-$(CONFIG_SENSORS_MAX20730)	+= max20730.o
 obj-$(CONFIG_SENSORS_MAX20751)	+= max20751.o
 obj-$(CONFIG_SENSORS_MAX20830)	+= max20830.o
+obj-$(CONFIG_SENSORS_MAX20860A)	+= max20860a.o
 obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
 obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
diff --git a/drivers/hwmon/pmbus/max20860a.c b/drivers/hwmon/pmbus/max20860a.c
new file mode 100644
index 000000000000..905f916f6c08
--- /dev/null
+++ b/drivers/hwmon/pmbus/max20860a.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for Analog Devices MAX20860A
+ *
+ * SPDX-FileCopyrightText: Copyright Hewlett Packard Enterprise Development LP
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regulator/driver.h>
+#include "pmbus.h"
+
+#if IS_ENABLED(CONFIG_SENSORS_MAX20860A_REGULATOR)
+static const struct regulator_desc max20860a_reg_desc[] = {
+	PMBUS_REGULATOR_ONE("vout"),
+};
+#endif
+
+static struct pmbus_driver_info max20860a_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
+		PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
+		PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_STATUS_INPUT,
+#if IS_ENABLED(CONFIG_SENSORS_MAX20860A_REGULATOR)
+	.num_regulators = 1,
+	.reg_desc = max20860a_reg_desc,
+#endif
+};
+
+static int max20860a_probe(struct i2c_client *client)
+{
+	return pmbus_do_probe(client, &max20860a_info);
+}
+
+static const struct i2c_device_id max20860a_id[] = {
+	{"max20860a"},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, max20860a_id);
+
+static const struct of_device_id max20860a_of_match[] = {
+	{ .compatible = "adi,max20860a" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, max20860a_of_match);
+
+static struct i2c_driver max20860a_driver = {
+	.driver = {
+		.name = "max20860a",
+		.of_match_table = max20860a_of_match,
+	},
+	.probe = max20860a_probe,
+	.id_table = max20860a_id,
+};
+
+module_i2c_driver(max20860a_driver);
+
+MODULE_AUTHOR("Syed Arif <arif.syed@hpe.com>");
+MODULE_AUTHOR("Sanman Pradhan <psanman@juniper.net>");
+MODULE_DESCRIPTION("PMBus driver for Analog Devices MAX20860A");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
-- 
2.34.1

Re: [PATCH v4 1/2] dt-bindings: hwmon: pmbus: Add Analog Devices MAX20860A

[sashiko-bot]

> From: Sanman Pradhan <psanman@juniper.net>
> 
> Add devicetree binding documentation for the Analog Devices MAX20860A
> step-down DC-DC switching regulator with PMBus interface.
> 
> Signed-off-by: Sanman Pradhan <psanman@juniper.net>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260601184516.919488-1-sanman.pradhan@hpe.com?part=1

Re: [PATCH v4 2/2] hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Mismatch between the driver's regulator node expectation and the device tree binding schema, causing DT regulator properties to be silently ignored and the regulator to be unusable by consumers.
--

commit 66bb21f2d9ec87355cc55cca84538b6ad8d8842c
Author: Syed Arif <arif.syed@hpe.com>

hwmon: (pmbus/max20860a) Add driver for Analog Devices MAX20860A

This commit adds a new PMBus driver for the Analog Devices MAX20860A
step-down DC-DC switching regulator. It provides hardware monitoring for
voltage, current, and temperature, along with optional regulator framework
support.

> diff --git a/drivers/hwmon/pmbus/max20860a.c b/drivers/hwmon/pmbus/max20860a.c
> new file mode 100644
> index 0000000000000..905f916f6c089
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/max20860a.c
[ ... ]
> @@ -0,0 +1,68 @@
[ ... ]
> +#include <linux/regulator/driver.h>
> +#include "pmbus.h"
> +
> +#if IS_ENABLED(CONFIG_SENSORS_MAX20860A_REGULATOR)
> +static const struct regulator_desc max20860a_reg_desc[] = {
> +	PMBUS_REGULATOR_ONE("vout"),

[Severity: High]
Will this prevent the regulator core from matching the device tree node?

The PMBUS_REGULATOR_ONE("vout") macro sets of_match to "vout". During
registration, the regulator core searches for a child node named "vout"
or a parent node with that exact name to associate the of_node.

If the device tree schema expects regulator properties directly on the
parent node (which is typically named generically, like regulator@xx),
will the regulator core fail to match the node?

If the match fails, the regulator is registered with of_node = NULL,
which silently ignores regulator constraints and prevents consumers
from referencing it as a supply.

> +};
> +#endif
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260601184516.919488-1-sanman.pradhan@hpe.com?part=2