Re: [PATCH 2/2] hwmon:(pmbus/xdpe1a2g7b) Add support for xdpe1a2g5b/7b controllers
From: Guenter Roeck
Date: Thu Feb 12 2026 - 23:58:45 EST
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
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:
ACK, We will take care of this in the next release.
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.
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 neededACK, We will take care of this in the next release.
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 provide comments 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.
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.
ACK, We will take care of this 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.
+
+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");