linux-kernel - Re: [PATCH v2 1/2] hwmon: (pmbus) Add support for MPS multi-phase mp2869a/mp29612a controllers

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Message-ID: <ac652108-68aa-49d1-a448-1c0ee6ca157e@roeck-us.net>
Date: Wed, 16 Jul 2025 13:36:47 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: tzuhao.wtmh@...il.com, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Jean Delvare <jdelvare@...e.com>,
 Jonathan Corbet <corbet@....net>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 Naresh Solanki <naresh.solanki@...ements.com>,
 Rodrigo Gobbi <rodrigo.gobbi.7@...il.com>, Fabio Estevam
 <festevam@...il.com>, Michal Simek <michal.simek@....com>,
 Henry Wu <Henry_Wu@...ntatw.com>, Grant Peltier <grantpeltier93@...il.com>,
 Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Cedric Encarnacion <cedricjustine.encarnacion@...log.com>,
 Nuno Sa <nuno.sa@...log.com>, Cherrence Sarip <cherrence.sarip@...log.com>,
 Jerome Brunet <jbrunet@...libre.com>, Leo Yang <leo.yang.sy0@...il.com>,
 John Erasmus Mari Geronimo <johnerasmusmari.geronimo@...log.com>,
 Kim Seer Paller <kimseer.paller@...log.com>,
 Alex Vdovydchenko <xzeol@...oo.com>, Ninad Palsule <ninad@...ux.ibm.com>,
 Mariel Tinaco <Mariel.Tinaco@...log.com>, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
 linux-doc@...r.kernel.org
Cc: peteryin.openbmc@...il.com
Subject: Re: [PATCH v2 1/2] hwmon: (pmbus) Add support for MPS multi-phase
 mp2869a/mp29612a controllers

On 6/30/25 04:20, tzuhao.wtmh@...il.com wrote:
> From: Henry Wu <Henry_Wu@...ntatw.com>
> 
> Add support for the mp2869a and mp29612a controllers from Monolithic Power
> Systems, Inc. (MPS). These are dual-loop, digital, multi-phase modulation
> controllers.
> 
> Signed-off-by: Henry Wu <Henry_Wu@...ntatw.com>
> ---
>   Documentation/hwmon/index.rst   |   1 +
>   Documentation/hwmon/mp2869a.rst |  86 +++++++++
>   drivers/hwmon/pmbus/Kconfig     |  10 ++
>   drivers/hwmon/pmbus/Makefile    |   1 +
>   drivers/hwmon/pmbus/mp2869a.c   | 299 ++++++++++++++++++++++++++++++++
>   5 files changed, 397 insertions(+)
>   create mode 100644 Documentation/hwmon/mp2869a.rst
>   create mode 100644 drivers/hwmon/pmbus/mp2869a.c
> 
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index b45bfb4ebf30..10bf4bd77f7b 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -172,6 +172,7 @@ Hardware Monitoring Kernel Drivers
>      menf21bmc
>      mlxreg-fan
>      mp2856
> +   mp2869a
>      mp2888
>      mp2891
>      mp2975
> diff --git a/Documentation/hwmon/mp2869a.rst b/Documentation/hwmon/mp2869a.rst
> new file mode 100644
> index 000000000000..a98ccb3d630d
> --- /dev/null
> +++ b/Documentation/hwmon/mp2869a.rst
> @@ -0,0 +1,86 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver mp2896a
> +=====================
> +
> +Supported chips:
> +
> +  * MPS MP2896A
> +
> +    Prefix: 'mp2896a'
> +
> +  * MPS MP29612A
> +
> +    Prefix: 'mp29612a'
> +
> +Author:
> +
> +    Henry Wu <Henry_WU@...ntatw.com>
> +
> +Description
> +-----------
> +
> +This driver implements support for Monolithic Power Systems, Inc. (MPS)
> +MP2896A, a digital, multi-phase voltage regulator controller with PMBus interface.
> +
> +This device:
> +
> +- Supports up to two power rails.
> +- Supports multiple PMBus pages for telemetry and configuration.
> +- Supports VOUT readout in **VID format only** (no support for direct format).
> +- Supports AMD SVI3 VID protocol with 5-mV/LSB resolution (if applicable).
> +- Uses vendor-specific registers for VOUT scaling and phase configuration.
> +
> +Device supports:
> +
> +- SVID interface.
> +- AVSBus interface.
> +
> +Device compliant with:
> +
> +- PMBus rev 1.3 interface.
> +
> +Sysfs Interface
> +---------------
> +
> +The driver provides the following sysfs attributes:
> +
> +**Current measurements:**
> +
> +- Index 1: "iin"
> +- Indexes 2, 3: "iout"
> +
> +**curr[1-3]_alarm**
> +**curr[1-3]_input**
> +**curr[1-3]_label**
> +
> +**Voltage measurements:**
> +
> +- Index 1: "vin"
> +- Indexes 2, 3: "vout"
> +
> +**in[1-3]_crit**
> +**in[1-3]_crit_alarm**
> +**in[1-3]_input**
> +**in[1-3]_label**
> +**in[1-3]_lcrit**
> +**in[1-3]_lcrit_alarm**
> +
> +**Power measurements:**
> +
> +- Index 1: "pin"
> +- Indexes 2, 3: "pout"
> +
> +**power[1-3]_alarm**
> +**power[1-3]_input**
> +**power[1-3]_label**
> +
> +**Temperature measurements:**
> +
> +**temp[1-2]_crit**
> +**temp[1-2]_crit_alarm**
> +**temp[1-2]_input**
> +**temp[1-2]_max**
> +**temp[1-2]_max_alarm**
> +
> +
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index 441f984a859d..93b558761cc6 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -364,6 +364,16 @@ config SENSORS_MP2856
>   	  This driver can also be built as a module. If so, the module will
>   	  be called mp2856.
>   
> +config SENSORS_MP2869A
> +	tristate "MP2869A PMBus sensor"
> +	depends on I2C && PMBUS
> +	help
> +	  If you say yes here you get support for the MPS MP2869A MP29612A
> +	  voltage regulator via the PMBus interface.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called mp2869a.
> +
>   config SENSORS_MP2888
>   	tristate "MPS MP2888"
>   	help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 29cd8a3317d2..42087d0dedbc 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
>   obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
>   obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
>   obj-$(CONFIG_SENSORS_MP2856)	+= mp2856.o
> +obj-$(CONFIG_SENSORS_MP2869A)   += mp2869a.o
>   obj-$(CONFIG_SENSORS_MP2888)	+= mp2888.o
>   obj-$(CONFIG_SENSORS_MP2891)	+= mp2891.o
>   obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
> diff --git a/drivers/hwmon/pmbus/mp2869a.c b/drivers/hwmon/pmbus/mp2869a.c
> new file mode 100644
> index 000000000000..e61f1380dbc1
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/mp2869a.c
> @@ -0,0 +1,299 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Hardware monitoring driver for MP2856A/MP29612A
> + * Monolithic Power Systems VR Controller
> + *
> + * Copyright (C) 2023 Quanta Computer lnc.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pmbus.h>
> +#include "pmbus.h"
> +
> +/* Vendor specific registers. */
> +#define MP2869A_VOUT_MODE			 0x20

Standard register.

> +#define MP2869A_VOUT_MODE_MASK		 GENMASK(7, 5)
> +#define MP2869A_VOUT_MODE_VID		 (0 << 5)
> +
> +#define MP2869A_READ_VOUT			 0x8b

Standard register.
> +
> +#define MP2869A_MFR_VOUT_SCALE_LOOP	 0x29

Standard register.

Guenter