[PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes

[PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes

[Guenter Roeck]

Some hardware monitoring chips support three alarm levels for current and
voltage high limits, and three alarm levels for voltage low limits.
Add support for currX_emergency, inX_emergency, and inX_lemergency
attributes together with the appropriate alarm attributes to support such
chips.

Cc: Manaf Meethalavalappu Pallikunhi <manaf.pallikunhi@oss.qualcomm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Also support inX_lemergency for voltage low emergency limits.

 Documentation/ABI/testing/sysfs-class-hwmon | 36 +++++++++++++++++++++
 Documentation/hwmon/sysfs-interface.rst     | 12 +++++++
 drivers/hwmon/hwmon.c                       |  6 ++++
 include/linux/hwmon.h                       | 12 +++++++
 4 files changed, 66 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-hwmon b/Documentation/ABI/testing/sysfs-class-hwmon
index b185bdfc7186..34df6d7bd5f8 100644
--- a/Documentation/ABI/testing/sysfs-class-hwmon
+++ b/Documentation/ABI/testing/sysfs-class-hwmon
@@ -61,6 +61,18 @@ Description:
 		take drastic action such as power down or reset. At the very
 		least, it should report a fault.
 
+What:		/sys/class/hwmon/hwmonX/inY_lemergency
+Description:
+		Voltage emergency min value.
+
+		Unit: millivolt
+
+		RW
+
+		If voltage drops to or below this limit, the system is
+		expected to take drastic action such as immediate power
+		down or reset. At the very least, it should report a fault.
+
 What:		/sys/class/hwmon/hwmonX/inY_max
 Description:
 		Voltage max value.
@@ -81,6 +93,18 @@ Description:
 		take drastic action such as power down or reset. At the very
 		least, it should report a fault.
 
+What:		/sys/class/hwmon/hwmonX/inY_emergency
+Description:
+		Voltage emergency max value.
+
+		Unit: millivolt
+
+		RW
+
+		If voltage reaches or exceeds this limit, the system is expected
+		to take drastic action such as immediate power down or reset.
+		At the very least, it should report a fault.
+
 What:		/sys/class/hwmon/hwmonX/inY_input
 Description:
 		Voltage input value.
@@ -647,6 +671,18 @@ Description:
 
 		RW
 
+What:		/sys/class/hwmon/hwmonX/currY_emergency
+Description:
+		Current emergency high value.
+
+		Unit: milliampere
+
+		RW
+
+		If a current reaches or exceeds this limit, the system is
+		expected to take drastic action such as immediate power down
+		or reset. At the very least, it should report a fault.
+
 What:		/sys/class/hwmon/hwmonX/currY_input
 Description:
 		Current input value
diff --git a/Documentation/hwmon/sysfs-interface.rst b/Documentation/hwmon/sysfs-interface.rst
index 94e1bbce172a..f7ab5d5c4d3a 100644
--- a/Documentation/hwmon/sysfs-interface.rst
+++ b/Documentation/hwmon/sysfs-interface.rst
@@ -121,12 +121,18 @@ Voltages
 `in[0-*]_lcrit`
 		Voltage critical min value.
 
+`in[0-*]_lemergency`
+		Voltage emergency min value.
+
 `in[0-*]_max`
 		Voltage max value.
 
 `in[0-*]_crit`
 		Voltage critical max value.
 
+`in[0-*]_emergency`
+		Voltage emergency max value.
+
 `in[0-*]_input`
 		Voltage input value.
 
@@ -332,6 +338,9 @@ Currents
 `curr[1-*]_crit`
 		Current critical high value.
 
+`curr[1-*]_emergency`
+		Current emergency high value.
+
 `curr[1-*]_input`
 		Current input value.
 
@@ -527,12 +536,15 @@ implementation.
 +-------------------------------+-----------------------+
 | **`in[0-*]_min_alarm`,	| Limit alarm		|
 | `in[0-*]_max_alarm`,		|			|
+| `in[0-*]_lemergency_alarm`,	|			|
 | `in[0-*]_lcrit_alarm`,	|   - 0: no alarm	|
 | `in[0-*]_crit_alarm`,		|   - 1: alarm		|
+| `in[0-*]_emergency_alarm`,	|			|
 | `curr[1-*]_min_alarm`,	|			|
 | `curr[1-*]_max_alarm`,	| RO			|
 | `curr[1-*]_lcrit_alarm`,	|			|
 | `curr[1-*]_crit_alarm`,	|			|
+| `curr[1-*]_emergency_alarm`,	|			|
 | `power[1-*]_cap_alarm`,	|			|
 | `power[1-*]_max_alarm`,	|			|
 | `power[1-*]_crit_alarm`,	|			|
diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 55a9a3ddd4aa..776ebb26c9c1 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -621,6 +621,8 @@ static const char * const hwmon_in_attr_templates[] = {
 	[hwmon_in_max] = "in%d_max",
 	[hwmon_in_lcrit] = "in%d_lcrit",
 	[hwmon_in_crit] = "in%d_crit",
+	[hwmon_in_lemergency] = "in%d_lemergency",
+	[hwmon_in_emergency] = "in%d_emergency",
 	[hwmon_in_average] = "in%d_average",
 	[hwmon_in_lowest] = "in%d_lowest",
 	[hwmon_in_highest] = "in%d_highest",
@@ -631,6 +633,8 @@ static const char * const hwmon_in_attr_templates[] = {
 	[hwmon_in_max_alarm] = "in%d_max_alarm",
 	[hwmon_in_lcrit_alarm] = "in%d_lcrit_alarm",
 	[hwmon_in_crit_alarm] = "in%d_crit_alarm",
+	[hwmon_in_lemergency_alarm] = "in%d_lemergency_alarm",
+	[hwmon_in_emergency_alarm] = "in%d_emergency_alarm",
 	[hwmon_in_rated_min] = "in%d_rated_min",
 	[hwmon_in_rated_max] = "in%d_rated_max",
 	[hwmon_in_beep] = "in%d_beep",
@@ -644,6 +648,7 @@ static const char * const hwmon_curr_attr_templates[] = {
 	[hwmon_curr_max] = "curr%d_max",
 	[hwmon_curr_lcrit] = "curr%d_lcrit",
 	[hwmon_curr_crit] = "curr%d_crit",
+	[hwmon_curr_emergency] = "curr%d_emergency",
 	[hwmon_curr_average] = "curr%d_average",
 	[hwmon_curr_lowest] = "curr%d_lowest",
 	[hwmon_curr_highest] = "curr%d_highest",
@@ -654,6 +659,7 @@ static const char * const hwmon_curr_attr_templates[] = {
 	[hwmon_curr_max_alarm] = "curr%d_max_alarm",
 	[hwmon_curr_lcrit_alarm] = "curr%d_lcrit_alarm",
 	[hwmon_curr_crit_alarm] = "curr%d_crit_alarm",
+	[hwmon_curr_emergency_alarm] = "curr%d_emergency_alarm",
 	[hwmon_curr_rated_min] = "curr%d_rated_min",
 	[hwmon_curr_rated_max] = "curr%d_rated_max",
 	[hwmon_curr_beep] = "curr%d_beep",
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 77a6f2bffcba..3a9d4446c6e0 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -134,6 +134,8 @@ enum hwmon_in_attributes {
 	hwmon_in_max,
 	hwmon_in_lcrit,
 	hwmon_in_crit,
+	hwmon_in_lemergency,
+	hwmon_in_emergency,
 	hwmon_in_average,
 	hwmon_in_lowest,
 	hwmon_in_highest,
@@ -144,6 +146,8 @@ enum hwmon_in_attributes {
 	hwmon_in_max_alarm,
 	hwmon_in_lcrit_alarm,
 	hwmon_in_crit_alarm,
+	hwmon_in_lemergency_alarm,
+	hwmon_in_emergency_alarm,
 	hwmon_in_rated_min,
 	hwmon_in_rated_max,
 	hwmon_in_beep,
@@ -156,6 +160,8 @@ enum hwmon_in_attributes {
 #define HWMON_I_MAX		BIT(hwmon_in_max)
 #define HWMON_I_LCRIT		BIT(hwmon_in_lcrit)
 #define HWMON_I_CRIT		BIT(hwmon_in_crit)
+#define HWMON_I_LEMERGENCY	BIT(hwmon_in_lemergency)
+#define HWMON_I_EMERGENCY	BIT(hwmon_in_emergency)
 #define HWMON_I_AVERAGE		BIT(hwmon_in_average)
 #define HWMON_I_LOWEST		BIT(hwmon_in_lowest)
 #define HWMON_I_HIGHEST		BIT(hwmon_in_highest)
@@ -166,6 +172,8 @@ enum hwmon_in_attributes {
 #define HWMON_I_MAX_ALARM	BIT(hwmon_in_max_alarm)
 #define HWMON_I_LCRIT_ALARM	BIT(hwmon_in_lcrit_alarm)
 #define HWMON_I_CRIT_ALARM	BIT(hwmon_in_crit_alarm)
+#define HWMON_I_LEMERGENCY_ALARM BIT(hwmon_in_lemergency_alarm)
+#define HWMON_I_EMERGENCY_ALARM	BIT(hwmon_in_emergency_alarm)
 #define HWMON_I_RATED_MIN	BIT(hwmon_in_rated_min)
 #define HWMON_I_RATED_MAX	BIT(hwmon_in_rated_max)
 #define HWMON_I_BEEP		BIT(hwmon_in_beep)
@@ -178,6 +186,7 @@ enum hwmon_curr_attributes {
 	hwmon_curr_max,
 	hwmon_curr_lcrit,
 	hwmon_curr_crit,
+	hwmon_curr_emergency,
 	hwmon_curr_average,
 	hwmon_curr_lowest,
 	hwmon_curr_highest,
@@ -188,6 +197,7 @@ enum hwmon_curr_attributes {
 	hwmon_curr_max_alarm,
 	hwmon_curr_lcrit_alarm,
 	hwmon_curr_crit_alarm,
+	hwmon_curr_emergency_alarm,
 	hwmon_curr_rated_min,
 	hwmon_curr_rated_max,
 	hwmon_curr_beep,
@@ -199,6 +209,7 @@ enum hwmon_curr_attributes {
 #define HWMON_C_MAX		BIT(hwmon_curr_max)
 #define HWMON_C_LCRIT		BIT(hwmon_curr_lcrit)
 #define HWMON_C_CRIT		BIT(hwmon_curr_crit)
+#define HWMON_C_EMERGENCY	BIT(hwmon_curr_emergency)
 #define HWMON_C_AVERAGE		BIT(hwmon_curr_average)
 #define HWMON_C_LOWEST		BIT(hwmon_curr_lowest)
 #define HWMON_C_HIGHEST		BIT(hwmon_curr_highest)
@@ -209,6 +220,7 @@ enum hwmon_curr_attributes {
 #define HWMON_C_MAX_ALARM	BIT(hwmon_curr_max_alarm)
 #define HWMON_C_LCRIT_ALARM	BIT(hwmon_curr_lcrit_alarm)
 #define HWMON_C_CRIT_ALARM	BIT(hwmon_curr_crit_alarm)
+#define HWMON_C_EMERGENCY_ALARM	BIT(hwmon_curr_emergency_alarm)
 #define HWMON_C_RATED_MIN	BIT(hwmon_curr_rated_min)
 #define HWMON_C_RATED_MAX	BIT(hwmon_curr_rated_max)
 #define HWMON_C_BEEP		BIT(hwmon_curr_beep)
-- 
2.45.2

Re: [PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Internal ABI breakage in the habanalabs driver caused by inserting values into hwmon enums.
--

--- Patch [1]: [PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes ---
commit 618b70e656b029d918a4d90557dfadbd253324dd
Author: Guenter Roeck <linux@roeck-us.net>

hwmon: Add support for currX_emergency and inX_[l]emergency attributes

This commit adds new emergency limit attributes for current and voltage to
the hardware monitoring subsystem. It updates the hwmon core code, the
enumerations, and the sysfs ABI documentation to support the new alarms.

> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
> index dd713e193d0c3..a3a7d27f3b5ff 100644
> --- a/include/linux/hwmon.h
> +++ b/include/linux/hwmon.h
> @@ -134,6 +134,8 @@ enum hwmon_in_attributes {
>  	hwmon_in_max,
>  	hwmon_in_lcrit,
>  	hwmon_in_crit,
> +	hwmon_in_lemergency,
> +	hwmon_in_emergency,

[Severity: High]
Does inserting these elements here break downstream drivers that rely on the
historical integer mapping?

For example, in drivers/accel/habanalabs/common/hwmon.c:adjust_hwmon_flags(),
the driver performs a hardcoded bitwise shift assuming the Linux hwmon enum
values perfectly match the firmware API shifted by 1:

    flags = (cpucp_flags << 1) | HWMON_I_ENABLE;

By inserting elements into the middle of this enum, all subsequent values
(like hwmon_in_average) shift by 2. This causes the habanalabs driver to
incorrectly map firmware sensors to Linux hwmon attributes. For instance,
inX_highest will map to inX_average, and reading from these incorrectly
mapped attributes via sysfs will fail with -EINVAL.

Can these new enum values be added to the end of the enum instead, or does
habanalabs need to be updated to decouple it from the hwmon enum ordering?

>  	hwmon_in_average,
>  	hwmon_in_lowest,
>  	hwmon_in_highest,

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260813211433.879638-1-linux@roeck-us.net?part=1

Re: [PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes

[Guenter Roeck]

On 8/13/26 18:20, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] Internal ABI breakage in the habanalabs driver caused by inserting values into hwmon enums.
> --
> 
> --- Patch [1]: [PATCH v2] hwmon: Add support for currX_emergency and inX_[l]emergency attributes ---
> commit 618b70e656b029d918a4d90557dfadbd253324dd
> Author: Guenter Roeck <linux@roeck-us.net>
> 
> hwmon: Add support for currX_emergency and inX_[l]emergency attributes
> 
> This commit adds new emergency limit attributes for current and voltage to
> the hardware monitoring subsystem. It updates the hwmon core code, the
> enumerations, and the sysfs ABI documentation to support the new alarms.
> 
>> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
>> index dd713e193d0c3..a3a7d27f3b5ff 100644
>> --- a/include/linux/hwmon.h
>> +++ b/include/linux/hwmon.h
>> @@ -134,6 +134,8 @@ enum hwmon_in_attributes {
>>   	hwmon_in_max,
>>   	hwmon_in_lcrit,
>>   	hwmon_in_crit,
>> +	hwmon_in_lemergency,
>> +	hwmon_in_emergency,
> 
> [Severity: High]
> Does inserting these elements here break downstream drivers that rely on the
> historical integer mapping?
> 
> For example, in drivers/accel/habanalabs/common/hwmon.c:adjust_hwmon_flags(),
> the driver performs a hardcoded bitwise shift assuming the Linux hwmon enum
> values perfectly match the firmware API shifted by 1:
> 
>      flags = (cpucp_flags << 1) | HWMON_I_ENABLE;
> 
> By inserting elements into the middle of this enum, all subsequent values
> (like hwmon_in_average) shift by 2. This causes the habanalabs driver to
> incorrectly map firmware sensors to Linux hwmon attributes. For instance,
> inX_highest will map to inX_average, and reading from these incorrectly
> mapped attributes via sysfs will fail with -EINVAL.
> 
> Can these new enum values be added to the end of the enum instead, or does
> habanalabs need to be updated to decouple it from the hwmon enum ordering?
> 

There is no guarantee of a specific ordering of those flags. They can and will change
position and/or ordering as new flags are added. The hwmon subsystem must not be held
hostage by some driver making up their own rules. FWIW, I don't even understand
what the habanalabs driver is doing and what assumptions it is making about the position
and ordering of the flags.

Guenter