Re: [PATCH v2 2/2] hwmon: (pmbus/max20830) add driver for max20830

Nuno Sá
2026-04-16T14:37:37Z

On Thu, Apr 16, 2026 at 03:59:11PM +0800, Alexis Czezar Torreno wrote:
> Add support for MAX20830 step-down DC-DC switching regulator with
> PMBus interface. It allows monitoring of input/output voltage,
> output current and temperature through the PMBus serial interface.
>
> Signed-off-by: Alexis Czezar Torreno <alexisczezar.torreno@analog.com>
> ---
> Documentation/hwmon/index.rst | 1 +
> Documentation/hwmon/max20830.rst | 49 +++++++++++++++++++++++
> MAINTAINERS | 2 +
> drivers/hwmon/pmbus/Kconfig | 9 +++++
> drivers/hwmon/pmbus/Makefile | 1 +
> drivers/hwmon/pmbus/max20830.c | 86 ++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 148 insertions(+)
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 8b655e5d6b68b90c697a52c7bf526e81d370caf7..56f7eb761be76dd627a2f34135abad05203b0582 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -158,6 +158,7 @@ Hardware Monitoring Kernel Drivers
> max197
> max20730
> max20751
> + max20830
> max31722
> max31730
> max31760
> diff --git a/Documentation/hwmon/max20830.rst b/Documentation/hwmon/max20830.rst
> new file mode 100644
> index 0000000000000000000000000000000000000000..936e409dcc5c0898dde27d782308d4a7e1357e73
> --- /dev/null
> +++ b/Documentation/hwmon/max20830.rst
> @@ -0,0 +1,49 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver max20830
> +======================
> +
> +Supported chips:
> +
> + * Analog Devices MAX20830
> +
> + Prefix: 'max20830'
> +
> + Addresses scanned: -
> +
> + Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/max20830.pdf
> +
> +Author:
> +
> + - Alexis Czezar Torreno <alexisczezar.torreno@analog.com>
> +
> +
> +Description
> +-----------
> +
> +This driver supports hardware monitoring for Analog Devices MAX20830
> +Step-Down Switching Regulator with PMBus Interface.
> +
> +The MAX20830 is a 2.7V to 16V, 30A 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.
> +
> +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
> +================= ========================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 031c743e979521a92ed9ac67915c178ce31727bd..d6a6745e2dae29c3b8f80bbe61c54a2f5ecd9f47 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15585,6 +15585,8 @@ L: linux-hwmon@vger.kernel.org
> S: Supported
> W: https://ez.analog.com/linux-software-drivers
> F: Documentation/devicetree/bindings/hwmon/pmbus/adi,max20830.yaml
> +F: Documentation/hwmon/max20830.rst
> +F: drivers/hwmon/pmbus/max20830.c
>
> MAX2175 SDR TUNER DRIVER
> M: Ramesh Shanmugasundaram <rashanmu@gmail.com>
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index 8f4bff375ecbc355f5ed3400855c2852ec2aa5ef..987705bf45b75b7b91ccc469247909f3c3f53d77 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -365,6 +365,15 @@ config SENSORS_MAX20751
> This driver can also be built as a module. If so, the module will
> be called max20751.
>
> +config SENSORS_MAX20830
> + tristate "Analog Devices MAX20830"
> + help
> + If you say yes here you get hardware monitoring support for Analog
> + Devices MAX20830.
> +
> + This driver can also be built as a module. If so, the module will
> + be called max20830.
> +
> config SENSORS_MAX31785
> tristate "Maxim MAX31785 and compatibles"
> help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 7129b62bc00f8a2e98de14004997752a856dfda2..bc52f930e0825a902a0dd1c9e2b44f2e8d577c35 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_SENSORS_MAX16601) += max16601.o
> obj-$(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_MAX31785) += max31785.o
> obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
> obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
> diff --git a/drivers/hwmon/pmbus/max20830.c b/drivers/hwmon/pmbus/max20830.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..21ea8b59150cb0564f1776ee08131bad7fdef003
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/max20830.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Hardware monitoring driver for Analog Devices MAX20830
> + *
> + * Copyright (C) 2026 Analog Devices, Inc.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include "pmbus.h"
> +
> +static struct pmbus_driver_info max20830_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_IOUT |
> + PMBUS_HAVE_TEMP |
> + PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
> + PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
> +};
> +
> +static int max20830_probe(struct i2c_client *client)
> +{
> + u8 buf[I2C_SMBUS_BLOCK_MAX + 1];

AI seems a bit paranoid but maybe to be on the safe side just initialize
the above buffer.

> + u8 len;
> + int ret;
> +
> + if (!i2c_check_functionality(client->adapter,
> + I2C_FUNC_SMBUS_READ_I2C_BLOCK))
> + return -ENODEV;
> +
> + /*
> + * Use i2c_smbus_read_i2c_block_data() instead of
> + * i2c_smbus_read_block_data() to support I2C controllers
> + * which do not support SMBus block reads.
> + */
> + ret = i2c_smbus_read_i2c_block_data(client, PMBUS_IC_DEVICE_ID,
> + I2C_SMBUS_BLOCK_MAX, buf);
> + if (ret < 0)
> + return dev_err_probe(&client->dev, ret,
> + "Failed to read IC_DEVICE_ID\n");
> +
> + /* First byte is the block length. */
> + len = buf[0];
> + if (len != 9)
> + return dev_err_probe(&client->dev, -ENODEV,
> + "Unexpected IC_DEVICE_ID response\n");
> +
> + buf[len] = '\0';

It looks like it has a point in the above though.

- Nuno Sá