Re: [PATCH 2/2] hwmon:(pmbus/xdpe1a2g7b) Add support for xdpe1a2g5b/7b controllers
From: ashish yadav
Date: Mon Feb 16 2026 - 00:51:11 EST
Hi Guenter,
I hope you are doing well.
Please find our response inline.
With Best Regards,
Ashish Yadav
On Fri, Feb 13, 2026 at 10:28 AM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> On 2/12/26 19:45, ashish yadav wrote:
> > Hi Guenter,
> >
> > I hope this email finds you well.
> >
> > I am reaching out to request your assistance with a specific inquiry
> > regarding the handling of loops/pages for different VOUT modes
> > independently.
> > The challenge I am facing is that the Linux kernel provides a single
> > "PSC_VOLTAGE_OUT" for the chip, which is not page-specific, making it
> > difficult to handle these different modes independently.
> >
> > I would greatly appreciate it if you could provide me with more
> > information or guidance on how to address this issue, as your
> > expertise in this area would be invaluable in helping me find a
> > solution.
> >
>
> Best idea I have at this point is to announce a single mode for all pages
> and convert values for pages with other modes. We _could_ enhance the pmbus
> code to support per-page modes, but that only makes sense if more than a
> single chip is affected and if this is a real problem.
>
> Practical question is if the chip supports this. So far I have not encountered
> a chip which does. Unfortunately Infineon doesn't provide datasheets for these
> chips, so it is impossible for me to determine if this is a real or a theoretic
> problem.
>
> Guenter
After discussing with the concerned Infineon team, We have decided to
move forward with the following approach:
XDPE1A2G5B and XDPE1A2G7B support both Linear and NVIDIA PWM VID Data
formats for VOUT_MODE.
The configuration options for both devices will be as follows:
1. Both Page 0 and Page 1 can be set to Linear
2. Both Page 0 and Page 1 can be set to VID (NVIDIA format)
Important Note:
Please note that configuring both loops/pages of the device
independently is not possible.
The following combinations are not supported:
1. Page 0: Linear, Page 1: VID
2. Page 0: VID, Page 1: Linear
I will document these details in the next version of the patch.
> > With Best Regards,
> > Ashish Yadav
> >
> >
> > On Thu, Feb 5, 2026 at 2:20 PM ashish yadav <ashishyadav78@xxxxxxxxx> wrote:
> >>
> >> Hi Guenter,
> >>
> >> Thank you for taking the time to review and provide feedback.
> >> I appreciate your input and insights.
> >> Please find my comments inline below.
> >>
> >> Best regards,
> >> Ashish Yadav
> >>
> >> On Mon, Feb 2, 2026 at 9:01 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> >>>
> >>> On 2/2/26 00:03, ASHISH YADAV wrote:
> >>>> From: Ashish Yadav <ashish.yadav@xxxxxxxxxxxx>
> >>>>
> >>>> Add the pmbus driver for Infineon Digital Multi-phase XDPE1A2G5B and
> >>>> XDPE1A2G7B controllers.
> >>>>
> >>>> XDPE1A2G5B controller supports Linear Data format for VOUT using VOUT_MODE
> >>>> command.
> >>>> XDPE1A2G7B controller supports Linear and VID Data format for VOUT using
> >>>> VOUT_MODE command.
> >>>>
> >>>> In case of vid mode in XDPE1A2G7B controller, NVIDIA PWM VID vrm_version
> >>>> is supported:
> >>>> Vout = 5mV * (VID-1) + 195mV
> >>>>
> >>>> Signed-off-by: Ashish Yadav <ashish.yadav@xxxxxxxxxxxx>
> >>>> ---
> >>>> drivers/hwmon/pmbus/Kconfig | 9 +++
> >>>> drivers/hwmon/pmbus/Makefile | 1 +
> >>>> drivers/hwmon/pmbus/pmbus.h | 2 +-
> >>>> drivers/hwmon/pmbus/pmbus_core.c | 4 ++
> >>>> drivers/hwmon/pmbus/xdpe1a2g7b.c | 115 +++++++++++++++++++++++++++++++
> >>>
> >>> Driver documentation missing.
> >>>
> >> ACK, We will take care of this in the next release.
> >>
> >>>> 5 files changed, 130 insertions(+), 1 deletion(-)
> >>>> create mode 100644 drivers/hwmon/pmbus/xdpe1a2g7b.c
> >>>>
> >>>> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> >>>> index f3fb94cebf1a..c6750bce446d 100644
> >>>> --- a/drivers/hwmon/pmbus/Kconfig
> >>>> +++ b/drivers/hwmon/pmbus/Kconfig
> >>>> @@ -684,6 +684,15 @@ config SENSORS_XDPE152
> >>>> This driver can also be built as a module. If so, the module will
> >>>> be called xdpe152c4.
> >>>>
> >>>> +config SENSORS_XDPE1A2G7B
> >>>> + tristate "Infineon XDPE1A2G7B"
> >>>> + help
> >>>> + If you say yes here you get hardware monitoring support for Infineon
> >>>> + XDPE1A2G5B and XDPE1A2G7B.
> >>>> +
> >>>> + This driver can also be built as a module. If so, the module will
> >>>> + be called xdpe1a2g7b.
> >>>> +
> >>>> config SENSORS_XDPE122
> >>>> tristate "Infineon XDPE122 family"
> >>>> help
> >>>> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> >>>> index 349a89b6d92e..620f24baa289 100644
> >>>> --- a/drivers/hwmon/pmbus/Makefile
> >>>> +++ b/drivers/hwmon/pmbus/Makefile
> >>>> @@ -67,6 +67,7 @@ obj-$(CONFIG_SENSORS_UCD9200) += ucd9200.o
> >>>> obj-$(CONFIG_SENSORS_XDP710) += xdp710.o
> >>>> obj-$(CONFIG_SENSORS_XDPE122) += xdpe12284.o
> >>>> obj-$(CONFIG_SENSORS_XDPE152) += xdpe152c4.o
> >>>> +obj-$(CONFIG_SENSORS_XDPE1A2G7B) += xdpe1a2g7b.o
> >>>> obj-$(CONFIG_SENSORS_ZL6100) += zl6100.o
> >>>> obj-$(CONFIG_SENSORS_PIM4328) += pim4328.o
> >>>> obj-$(CONFIG_SENSORS_CRPS) += crps.o
> >>>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> >>>> index d2e9bfb5320f..3ddcb742d289 100644
> >>>> --- a/drivers/hwmon/pmbus/pmbus.h
> >>>> +++ b/drivers/hwmon/pmbus/pmbus.h
> >>>> @@ -416,7 +416,7 @@ enum pmbus_sensor_classes {
> >>>> #define PMBUS_PAGE_VIRTUAL BIT(31) /* Page is virtual */
> >>>>
> >>>> enum pmbus_data_format { linear = 0, ieee754, direct, vid };
> >>>> -enum vrm_version { vr11 = 0, vr12, vr13, imvp9, amd625mv };
> >>>> +enum vrm_version { vr11 = 0, vr12, vr13, imvp9, amd625mv, nvidia195mv };
> >>>>
> >>>> /* PMBus revision identifiers */
> >>>> #define PMBUS_REV_10 0x00 /* PMBus revision 1.0 */
> >>>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> >>>> index be6d05def115..4d7634ee6148 100644
> >>>> --- a/drivers/hwmon/pmbus/pmbus_core.c
> >>>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> >>>> @@ -885,6 +885,10 @@ static s64 pmbus_reg2data_vid(struct pmbus_data *data,
> >>>> if (val >= 0x0 && val <= 0xd8)
> >>>> rv = DIV_ROUND_CLOSEST(155000 - val * 625, 100);
> >>>> break;
> >>>> + case nvidia195mv:
> >>>> + if (val >= 0x01)
> >>>> + rv = 195 + (val - 1) * 5; /* VID step is 5mv */
> >>>> + break;
> >>>> }
> >>>> return rv;
> >>>> }
> >>>
> >>> The core change needs to be a separate patch.
> >>>
> >> ACK, We will take care of this in the next release.
> >>
> >>>> diff --git a/drivers/hwmon/pmbus/xdpe1a2g7b.c b/drivers/hwmon/pmbus/xdpe1a2g7b.c
> >>>> new file mode 100644
> >>>> index 000000000000..79b12b56e7b6
> >>>> --- /dev/null
> >>>> +++ b/drivers/hwmon/pmbus/xdpe1a2g7b.c
> >>>> @@ -0,0 +1,115 @@
> >>>> +// SPDX-License-Identifier: GPL-2.0+
> >>>> +/*
> >>>> + * Hardware monitoring driver for Infineon Multi-phase Digital XDPE1A2G5B
> >>>> + * and XDPE1A2G7B Controllers
> >>>> + *
> >>>> + * Copyright (c) 2026 Infineon Technologies. All rights reserved.
> >>>> + */
> >>>> +
> >>>> +#include <linux/err.h>
> >>>> +#include <linux/i2c.h>
> >>>> +#include <linux/init.h>
> >>>> +#include <linux/kernel.h>
> >>>> +#include <linux/module.h>
> >>>> +#include "pmbus.h"
> >>>> +
> >>>> +#define XDPE1A2G7B_PAGE_NUM 2
> >>>> +#define XDPE1A2G7B_NVIDIA_195MV 0x1E /* NVIDIA mode 1.95mV, VID step is 5mV */
> >>>> +
> >>>> +static int xdpe1a2g7b_identify(struct i2c_client *client,
> >>>> + struct pmbus_driver_info *info)
> >>>> +{
> >>>> + u8 vout_params;
> >>>> + int i, ret, vout_mode;
> >>>> +
> >>>> + vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
> >>>> + if (vout_mode >= 0 && vout_mode != 0xff) {
> >>>
> >>> What if vout_mode < 0 ? Also, what if the mode is different for page 1 ?
> >>
> >> ACK, We will take care of this in the next release.
> >>
> >>> Also, if I understand patch 0 correctly, executing this function is not needed
> >>> for XDPE1A2G5B.
> >>>
> >> ACK, We will take care of this in the next release.
> >>
> >>>> + switch (vout_mode >> 5) {
> >>>> + case 0:
> >>>> + info->format[PSC_VOLTAGE_OUT] = linear;
> >>>> + return 0;
> >>>> + case 1:
> >>>> + info->format[PSC_VOLTAGE_OUT] = vid;
> >>>> + break;
> >>>> + default:
> >>>> + return -ENODEV;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + for (i = 0; i < info->pages; i++) {
> >>>> + /* Read the VOUT_MODE register for VID Code Type. */
> >>>> + ret = pmbus_read_byte_data(client, i, PMBUS_VOUT_MODE);
> >>>
> >>> Given that there are only two pages, reading PMBUS_VOUT_MODE for
> >>> page 0 twice is a bit of a waste. On top of that, the need for the loop
> >>> suggests that the mode can be different across pages. That needs to be
> >>> supported: Bailing out in that case is not acceptable. Worse:
> >>> What if the mode is linear on page 0 but vid on page 1 ?
> >>>
> >> ACK, We will take care of this in the next release.
> >>
> >>>> + if (ret < 0)
> >>>> + return ret;
> >>>> +
> >>>> + vout_params = ret & GENMASK(4, 0);
> >>>> + switch (vout_params) {
> >>>> + case XDPE1A2G7B_NVIDIA_195MV:
> >>>> + info->vrm_version[i] = nvidia195mv;
> >>>> + break;
> >>>> + default:
> >>>> + return -EINVAL;
> >>>
> >>> This warrants an error message and an explanation (comment) why other modes
> >>> are not supported by the driver. The detailed datasheet is not public, so
> >>> you'll have to help out here. As mentioned above, bailing out because the
> >>> mode on page 1 is linear is not acceptable.
> >>>
> >> ACK, we will provide comments in the next release.
> >> Additionally, please note that the XDPE1A2G7B Controller only supports
> >> the 'nvidia195mv' vrm_version in the VID Data format for VOUT.
> >> We will ensure that this limitation is properly documented and
> >> commented on in the next release.
> >>
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static struct pmbus_driver_info xdpe1a2g7b_info = {
> >>>> + .pages = XDPE1A2G7B_PAGE_NUM,
> >>>> + .identify = xdpe1a2g7b_identify,
> >>>> + .format[PSC_VOLTAGE_IN] = linear,
> >>>> + .format[PSC_TEMPERATURE] = linear,
> >>>> + .format[PSC_CURRENT_IN] = linear,
> >>>> + .format[PSC_CURRENT_OUT] = linear,
> >>>> + .format[PSC_POWER] = linear,
> >>>> + .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
> >>>> + PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> >>>> + PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP |
> >>>> + PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | PMBUS_HAVE_STATUS_INPUT,
> >>>> + .func[1] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
> >>>> + PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> >>>> + PMBUS_HAVE_PIN | PMBUS_HAVE_POUT | PMBUS_HAVE_STATUS_INPUT,
> >>>> +};
> >>>> +
> >>>> +static int xdpe1a2g7b_probe(struct i2c_client *client)
> >>>> +{
> >>>> + struct pmbus_driver_info *info;
> >>>> +
> >>>> + info = devm_kmemdup(&client->dev, &xdpe1a2g7b_info, sizeof(*info),
> >>>> + GFP_KERNEL);
> >>>> + if (!info)
> >>>> + return -ENOMEM;
> >>>> +
> >>>> + return pmbus_do_probe(client, info);
> >>>> +}
> >>>> +
> >>>> +static const struct i2c_device_id xdpe1a2g7b_id[] = { { "xdpe1a2g5b" },
> >>>> + { "xdpe1a2g7b" },
> >>>> + {} };
> >>>
> >>> Please use more lines and less indentation.
> >>>
> >> ACK, We will take care of this in the next release.
> >>
> >>>> +
> >>>> +MODULE_DEVICE_TABLE(i2c, xdpe1a2g7b_id);
> >>>> +
> >>>> +static const struct of_device_id __maybe_unused xdpe1a2g7b_of_match[] = {
> >>>> + { .compatible = "infineon,xdpe1a2g5b" },
> >>>> + { .compatible = "infineon,xdpe1a2g7b" },
> >>>> + {}
> >>>
> >>> ... just like here.
> >>>
> >>>> +};
> >>>> +
> >>>> +MODULE_DEVICE_TABLE(of, xdpe1a2g7b_of_match);
> >>>> +
> >>>> +static struct i2c_driver xdpe1a2g7b_driver = {
> >>>> + .driver = {
> >>>> + .name = "xdpe1a2g7b",
> >>>> + .of_match_table = of_match_ptr(xdpe1a2g7b_of_match),
> >>>> + },
> >>>> + .probe = xdpe1a2g7b_probe,
> >>>> + .id_table = xdpe1a2g7b_id,
> >>>> +};
> >>>> +
> >>>> +module_i2c_driver(xdpe1a2g7b_driver);
> >>>> +
> >>>> +MODULE_AUTHOR("Ashish Yadav <ashish.yadav@xxxxxxxxxxxx>");
> >>>> +MODULE_DESCRIPTION("PMBus driver for Infineon XDPE1A2G5B/7B");
> >>>> +MODULE_LICENSE("GPL");
> >>>> +MODULE_IMPORT_NS("PMBUS");
> >>>
>