diff mbox series

[v3,2/2] ACPI: fan: Add hwmon support

Message ID 20240412160857.79858-2-W_Armin@gmx.de (mailing list archive)
State Superseded, archived
Headers show
Series [v3,1/2] hwmon: (core) Add support for power fault attribute | expand

Commit Message

Armin Wolf April 12, 2024, 4:08 p.m. UTC
Currently, the driver does only support a custom sysfs
to allow userspace to read the fan speed.
Add support for the standard hwmon interface so users
can read the fan speed with standard tools like "sensors".

Compile-tested only.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
Changes since v2:
- add support for fanX_target and power attrs

Changes since v1:
- fix undefined reference error
- fix fan speed validation
- coding style fixes
- clarify that the changes are compile-tested only
- add hwmon maintainers to cc list

The changes will be tested by Mikael Lund Jepsen from Danelec and
should be merged only after those tests.
---
 drivers/acpi/Makefile    |   1 +
 drivers/acpi/fan.h       |   9 +++
 drivers/acpi/fan_core.c  |   4 ++
 drivers/acpi/fan_hwmon.c | 148 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 162 insertions(+)
 create mode 100644 drivers/acpi/fan_hwmon.c

--
2.39.2

Comments

Guenter Roeck April 12, 2024, 4:41 p.m. UTC | #1
On Fri, Apr 12, 2024 at 06:08:57PM +0200, Armin Wolf wrote:
> Currently, the driver does only support a custom sysfs
> to allow userspace to read the fan speed.
> Add support for the standard hwmon interface so users
> can read the fan speed with standard tools like "sensors".
> 
> Compile-tested only.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
> Changes since v2:
> - add support for fanX_target and power attrs
> 
> Changes since v1:
> - fix undefined reference error
> - fix fan speed validation
> - coding style fixes
> - clarify that the changes are compile-tested only
> - add hwmon maintainers to cc list
> 
> The changes will be tested by Mikael Lund Jepsen from Danelec and
> should be merged only after those tests.
> ---
>  drivers/acpi/Makefile    |   1 +
>  drivers/acpi/fan.h       |   9 +++
>  drivers/acpi/fan_core.c  |   4 ++
>  drivers/acpi/fan_hwmon.c | 148 +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 162 insertions(+)
>  create mode 100644 drivers/acpi/fan_hwmon.c
> 
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 39ea5cfa8326..61ca4afe83dc 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_ACPI_TINY_POWER_BUTTON)	+= tiny-power-button.o
>  obj-$(CONFIG_ACPI_FAN)		+= fan.o
>  fan-objs			:= fan_core.o
>  fan-objs			+= fan_attr.o
> +fan-$(CONFIG_HWMON)		+= fan_hwmon.o
> 
>  obj-$(CONFIG_ACPI_VIDEO)	+= video.o
>  obj-$(CONFIG_ACPI_TAD)		+= acpi_tad.o
> diff --git a/drivers/acpi/fan.h b/drivers/acpi/fan.h
> index f89d19c922dc..db25a3898af7 100644
> --- a/drivers/acpi/fan.h
> +++ b/drivers/acpi/fan.h
> @@ -10,6 +10,8 @@
>  #ifndef _ACPI_FAN_H_
>  #define _ACPI_FAN_H_
> 
> +#include <linux/kconfig.h>
> +
>  #define ACPI_FAN_DEVICE_IDS	\
>  	{"INT3404", }, /* Fan */ \
>  	{"INTC1044", }, /* Fan for Tiger Lake generation */ \
> @@ -57,4 +59,11 @@ struct acpi_fan {
>  int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst);
>  int acpi_fan_create_attributes(struct acpi_device *device);
>  void acpi_fan_delete_attributes(struct acpi_device *device);
> +
> +#if IS_REACHABLE(CONFIG_HWMON)
> +int devm_acpi_fan_create_hwmon(struct acpi_device *device);
> +#else
> +static inline int devm_acpi_fan_create_hwmon(struct acpi_device *device) { return 0; };
> +#endif
> +
>  #endif
> diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
> index ff72e4ef8738..7cea4495f19b 100644
> --- a/drivers/acpi/fan_core.c
> +++ b/drivers/acpi/fan_core.c
> @@ -336,6 +336,10 @@ static int acpi_fan_probe(struct platform_device *pdev)
>  		if (result)
>  			return result;
> 
> +		result = devm_acpi_fan_create_hwmon(device);
> +		if (result)
> +			return result;
> +
>  		result = acpi_fan_create_attributes(device);
>  		if (result)
>  			return result;
> diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c
> new file mode 100644
> index 000000000000..57216ba872db
> --- /dev/null
> +++ b/drivers/acpi/fan_hwmon.c
> @@ -0,0 +1,148 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * fan_hwmon.c - hwmon interface for the ACPI Fan driver
> + *
> + * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/hwmon.h>
> +#include <linux/limits.h>
> +#include <linux/units.h>
> +
> +#include "fan.h"
> +
> +/* Returned when the ACPI fan does not support speed reporting */
> +#define FAN_SPEED_UNAVAILABLE	0xffffffff
> +#define FAN_POWER_UNAVAILABLE	0xffffffff
> +
> +static struct acpi_fan_fps *acpi_fan_get_current_fps(struct acpi_fan *fan, u64 control)
> +{
> +	int i;
> +
> +	for (i = 0; i < fan->fps_count; i++) {
> +		if (fan->fps[i].control == control)
> +			return &fan->fps[i];
> +	}
> +
> +	return NULL;
> +}
> +
> +static umode_t acpi_fan_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
> +				   int channel)
> +{
> +	return 0444;
> +}
> +
> +static int acpi_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
> +			 long *val)
> +{
> +	struct acpi_device *adev = dev_get_drvdata(dev);
> +	struct acpi_fan *fan = acpi_driver_data(adev);
> +	struct acpi_fan_fps *fps;
> +	struct acpi_fan_fst fst;
> +	int ret;
> +
> +	ret = acpi_fan_get_fst(adev, &fst);
> +	if (ret < 0)
> +		return ret;
> +
> +	switch (type) {
> +	case hwmon_fan:
> +		switch (attr) {
> +		case hwmon_fan_input:
> +			if (fst.speed == FAN_SPEED_UNAVAILABLE)
> +				return -ENODATA;
> +
> +			if (fst.speed > LONG_MAX)
> +				return -EOVERFLOW;
> +
> +			*val = fst.speed;
> +			return 0;
> +		case hwmon_fan_target:
> +			fps = acpi_fan_get_current_fps(fan, fst.control);
> +			if (!fps)
> +				return -ENODATA;
> +
> +			*val = fps->speed;
> +			return 0;
> +		case hwmon_fan_fault:
> +			*val = (fst.speed == FAN_SPEED_UNAVAILABLE);

Is it documented that this is indeed a fault (broken fan) ?

> +			return 0;
> +		default:
> +			break;
> +		}
> +		break;
> +	case hwmon_power:
> +		fps = acpi_fan_get_current_fps(fan, fst.control);
> +		if (!fps)
> +			return -ENODATA;
> +
> +		switch (attr) {
> +		case hwmon_power_input:
> +			if (fps->power == FAN_POWER_UNAVAILABLE)
> +				return -ENODATA;
> +
> +			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
> +				return -EOVERFLOW;
> +
> +			*val = fps->power * MICROWATT_PER_MILLIWATT;
> +			return 0;
> +		case hwmon_power_fault:
> +			*val = (fps->power == FAN_POWER_UNAVAILABLE);

Is it documented that this is indeed a power supply failure ?
What if the value is simply not reported ? "UNAVAILABLE" is not
commonly associated with a "fault".

Guenter

> +			return 0;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return -EOPNOTSUPP;
> +}
> +
> +static const struct hwmon_ops acpi_fan_ops = {
> +	.is_visible = acpi_fan_is_visible,
> +	.read = acpi_fan_read,
> +};
> +
> +static const struct hwmon_channel_info * const acpi_fan_info[] = {
> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET |  HWMON_F_FAULT),
> +	HWMON_CHANNEL_INFO(power, HWMON_P_INPUT | HWMON_P_FAULT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info acpi_fan_chip_info = {
> +	.ops = &acpi_fan_ops,
> +	.info = acpi_fan_info,
> +};
> +
> +static const struct hwmon_channel_info * const acpi_fan_fine_grain_info[] = {
> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info acpi_fan_fine_grain_chip_info = {
> +	.ops = &acpi_fan_ops,
> +	.info = acpi_fan_fine_grain_info,
> +};
> +
> +int devm_acpi_fan_create_hwmon(struct acpi_device *device)
> +{
> +	struct acpi_fan *fan = acpi_driver_data(device);
> +	const struct hwmon_chip_info *info;
> +	struct device *hdev;
> +
> +	/* When in fine grain control mode, not every fan control value
> +	 * has an associated fan performance state.
> +	 */
> +	if (fan->fif.fine_grain_ctrl)
> +		info = &acpi_fan_fine_grain_chip_info;
> +	else
> +		info = &acpi_fan_chip_info;
> +
> +	hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", device, info, NULL);
> +
> +	return PTR_ERR_OR_ZERO(hdev);
> +}
> --
> 2.39.2
>
Armin Wolf April 12, 2024, 8:27 p.m. UTC | #2
Am 12.04.24 um 18:41 schrieb Guenter Roeck:

> On Fri, Apr 12, 2024 at 06:08:57PM +0200, Armin Wolf wrote:
>> Currently, the driver does only support a custom sysfs
>> to allow userspace to read the fan speed.
>> Add support for the standard hwmon interface so users
>> can read the fan speed with standard tools like "sensors".
>>
>> Compile-tested only.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>> Changes since v2:
>> - add support for fanX_target and power attrs
>>
>> Changes since v1:
>> - fix undefined reference error
>> - fix fan speed validation
>> - coding style fixes
>> - clarify that the changes are compile-tested only
>> - add hwmon maintainers to cc list
>>
>> The changes will be tested by Mikael Lund Jepsen from Danelec and
>> should be merged only after those tests.
>> ---
>>   drivers/acpi/Makefile    |   1 +
>>   drivers/acpi/fan.h       |   9 +++
>>   drivers/acpi/fan_core.c  |   4 ++
>>   drivers/acpi/fan_hwmon.c | 148 +++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 162 insertions(+)
>>   create mode 100644 drivers/acpi/fan_hwmon.c
>>
>> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
>> index 39ea5cfa8326..61ca4afe83dc 100644
>> --- a/drivers/acpi/Makefile
>> +++ b/drivers/acpi/Makefile
>> @@ -77,6 +77,7 @@ obj-$(CONFIG_ACPI_TINY_POWER_BUTTON)	+= tiny-power-button.o
>>   obj-$(CONFIG_ACPI_FAN)		+= fan.o
>>   fan-objs			:= fan_core.o
>>   fan-objs			+= fan_attr.o
>> +fan-$(CONFIG_HWMON)		+= fan_hwmon.o
>>
>>   obj-$(CONFIG_ACPI_VIDEO)	+= video.o
>>   obj-$(CONFIG_ACPI_TAD)		+= acpi_tad.o
>> diff --git a/drivers/acpi/fan.h b/drivers/acpi/fan.h
>> index f89d19c922dc..db25a3898af7 100644
>> --- a/drivers/acpi/fan.h
>> +++ b/drivers/acpi/fan.h
>> @@ -10,6 +10,8 @@
>>   #ifndef _ACPI_FAN_H_
>>   #define _ACPI_FAN_H_
>>
>> +#include <linux/kconfig.h>
>> +
>>   #define ACPI_FAN_DEVICE_IDS	\
>>   	{"INT3404", }, /* Fan */ \
>>   	{"INTC1044", }, /* Fan for Tiger Lake generation */ \
>> @@ -57,4 +59,11 @@ struct acpi_fan {
>>   int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst);
>>   int acpi_fan_create_attributes(struct acpi_device *device);
>>   void acpi_fan_delete_attributes(struct acpi_device *device);
>> +
>> +#if IS_REACHABLE(CONFIG_HWMON)
>> +int devm_acpi_fan_create_hwmon(struct acpi_device *device);
>> +#else
>> +static inline int devm_acpi_fan_create_hwmon(struct acpi_device *device) { return 0; };
>> +#endif
>> +
>>   #endif
>> diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
>> index ff72e4ef8738..7cea4495f19b 100644
>> --- a/drivers/acpi/fan_core.c
>> +++ b/drivers/acpi/fan_core.c
>> @@ -336,6 +336,10 @@ static int acpi_fan_probe(struct platform_device *pdev)
>>   		if (result)
>>   			return result;
>>
>> +		result = devm_acpi_fan_create_hwmon(device);
>> +		if (result)
>> +			return result;
>> +
>>   		result = acpi_fan_create_attributes(device);
>>   		if (result)
>>   			return result;
>> diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c
>> new file mode 100644
>> index 000000000000..57216ba872db
>> --- /dev/null
>> +++ b/drivers/acpi/fan_hwmon.c
>> @@ -0,0 +1,148 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * fan_hwmon.c - hwmon interface for the ACPI Fan driver
>> + *
>> + * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de>
>> + */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/limits.h>
>> +#include <linux/units.h>
>> +
>> +#include "fan.h"
>> +
>> +/* Returned when the ACPI fan does not support speed reporting */
>> +#define FAN_SPEED_UNAVAILABLE	0xffffffff
>> +#define FAN_POWER_UNAVAILABLE	0xffffffff
>> +
>> +static struct acpi_fan_fps *acpi_fan_get_current_fps(struct acpi_fan *fan, u64 control)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < fan->fps_count; i++) {
>> +		if (fan->fps[i].control == control)
>> +			return &fan->fps[i];
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +static umode_t acpi_fan_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
>> +				   int channel)
>> +{
>> +	return 0444;
>> +}
>> +
>> +static int acpi_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
>> +			 long *val)
>> +{
>> +	struct acpi_device *adev = dev_get_drvdata(dev);
>> +	struct acpi_fan *fan = acpi_driver_data(adev);
>> +	struct acpi_fan_fps *fps;
>> +	struct acpi_fan_fst fst;
>> +	int ret;
>> +
>> +	ret = acpi_fan_get_fst(adev, &fst);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	switch (type) {
>> +	case hwmon_fan:
>> +		switch (attr) {
>> +		case hwmon_fan_input:
>> +			if (fst.speed == FAN_SPEED_UNAVAILABLE)
>> +				return -ENODATA;
>> +
>> +			if (fst.speed > LONG_MAX)
>> +				return -EOVERFLOW;
>> +
>> +			*val = fst.speed;
>> +			return 0;
>> +		case hwmon_fan_target:
>> +			fps = acpi_fan_get_current_fps(fan, fst.control);
>> +			if (!fps)
>> +				return -ENODATA;
>> +
>> +			*val = fps->speed;
>> +			return 0;
>> +		case hwmon_fan_fault:
>> +			*val = (fst.speed == FAN_SPEED_UNAVAILABLE);
> Is it documented that this is indeed a fault (broken fan) ?
>
Hi,

it actually means that the fan does not support speed reporting.

>> +			return 0;
>> +		default:
>> +			break;
>> +		}
>> +		break;
>> +	case hwmon_power:
>> +		fps = acpi_fan_get_current_fps(fan, fst.control);
>> +		if (!fps)
>> +			return -ENODATA;
>> +
>> +		switch (attr) {
>> +		case hwmon_power_input:
>> +			if (fps->power == FAN_POWER_UNAVAILABLE)
>> +				return -ENODATA;
>> +
>> +			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
>> +				return -EOVERFLOW;
>> +
>> +			*val = fps->power * MICROWATT_PER_MILLIWATT;
>> +			return 0;
>> +		case hwmon_power_fault:
>> +			*val = (fps->power == FAN_POWER_UNAVAILABLE);
> Is it documented that this is indeed a power supply failure ?
> What if the value is simply not reported ? "UNAVAILABLE" is not
> commonly associated with a "fault".
>
> Guenter
>
FAN_POWER_UNAVAILABLE signals that the power value is not supported.
Would it be more suitable to drop the fault attributes and just return -ENODATA in such a case?

Thanks,
Armin Wolf

>> +			return 0;
>> +		default:
>> +			break;
>> +		}
>> +		break;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	return -EOPNOTSUPP;
>> +}
>> +
>> +static const struct hwmon_ops acpi_fan_ops = {
>> +	.is_visible = acpi_fan_is_visible,
>> +	.read = acpi_fan_read,
>> +};
>> +
>> +static const struct hwmon_channel_info * const acpi_fan_info[] = {
>> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET |  HWMON_F_FAULT),
>> +	HWMON_CHANNEL_INFO(power, HWMON_P_INPUT | HWMON_P_FAULT),
>> +	NULL
>> +};
>> +
>> +static const struct hwmon_chip_info acpi_fan_chip_info = {
>> +	.ops = &acpi_fan_ops,
>> +	.info = acpi_fan_info,
>> +};
>> +
>> +static const struct hwmon_channel_info * const acpi_fan_fine_grain_info[] = {
>> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT),
>> +	NULL
>> +};
>> +
>> +static const struct hwmon_chip_info acpi_fan_fine_grain_chip_info = {
>> +	.ops = &acpi_fan_ops,
>> +	.info = acpi_fan_fine_grain_info,
>> +};
>> +
>> +int devm_acpi_fan_create_hwmon(struct acpi_device *device)
>> +{
>> +	struct acpi_fan *fan = acpi_driver_data(device);
>> +	const struct hwmon_chip_info *info;
>> +	struct device *hdev;
>> +
>> +	/* When in fine grain control mode, not every fan control value
>> +	 * has an associated fan performance state.
>> +	 */
>> +	if (fan->fif.fine_grain_ctrl)
>> +		info = &acpi_fan_fine_grain_chip_info;
>> +	else
>> +		info = &acpi_fan_chip_info;
>> +
>> +	hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", device, info, NULL);
>> +
>> +	return PTR_ERR_OR_ZERO(hdev);
>> +}
>> --
>> 2.39.2
>>
Guenter Roeck April 12, 2024, 9:01 p.m. UTC | #3
On Fri, Apr 12, 2024 at 10:27:56PM +0200, Armin Wolf wrote:
> > > +		case hwmon_fan_fault:
> > > +			*val = (fst.speed == FAN_SPEED_UNAVAILABLE);
> > Is it documented that this is indeed a fault (broken fan) ?
> > 
> Hi,
> 
> it actually means that the fan does not support speed reporting.
> 
> > > +			return 0;
> > > +		default:
> > > +			break;
> > > +		}
> > > +		break;
> > > +	case hwmon_power:
> > > +		fps = acpi_fan_get_current_fps(fan, fst.control);
> > > +		if (!fps)
> > > +			return -ENODATA;
> > > +
> > > +		switch (attr) {
> > > +		case hwmon_power_input:
> > > +			if (fps->power == FAN_POWER_UNAVAILABLE)
> > > +				return -ENODATA;
> > > +
> > > +			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
> > > +				return -EOVERFLOW;
> > > +
> > > +			*val = fps->power * MICROWATT_PER_MILLIWATT;
> > > +			return 0;
> > > +		case hwmon_power_fault:
> > > +			*val = (fps->power == FAN_POWER_UNAVAILABLE);
> > Is it documented that this is indeed a power supply failure ?
> > What if the value is simply not reported ? "UNAVAILABLE" is not
> > commonly associated with a "fault".
> > 
> > Guenter
> > 
> FAN_POWER_UNAVAILABLE signals that the power value is not supported.
> Would it be more suitable to drop the fault attributes and just return -ENODATA in such a case?
> 

There should be no fault attributes unless a real fault
is reported, and if power reporting is not supported the
hwmon_power_input attribute should not even be created.

The same really applies to the fan speed atribute: If reading
the fan speed is not supported, the attribute should not even
exist.

Guenter
Armin Wolf April 12, 2024, 11:18 p.m. UTC | #4
Am 12.04.24 um 23:01 schrieb Guenter Roeck:

> On Fri, Apr 12, 2024 at 10:27:56PM +0200, Armin Wolf wrote:
>>>> +		case hwmon_fan_fault:
>>>> +			*val = (fst.speed == FAN_SPEED_UNAVAILABLE);
>>> Is it documented that this is indeed a fault (broken fan) ?
>>>
>> Hi,
>>
>> it actually means that the fan does not support speed reporting.
>>
>>>> +			return 0;
>>>> +		default:
>>>> +			break;
>>>> +		}
>>>> +		break;
>>>> +	case hwmon_power:
>>>> +		fps = acpi_fan_get_current_fps(fan, fst.control);
>>>> +		if (!fps)
>>>> +			return -ENODATA;
>>>> +
>>>> +		switch (attr) {
>>>> +		case hwmon_power_input:
>>>> +			if (fps->power == FAN_POWER_UNAVAILABLE)
>>>> +				return -ENODATA;
>>>> +
>>>> +			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
>>>> +				return -EOVERFLOW;
>>>> +
>>>> +			*val = fps->power * MICROWATT_PER_MILLIWATT;
>>>> +			return 0;
>>>> +		case hwmon_power_fault:
>>>> +			*val = (fps->power == FAN_POWER_UNAVAILABLE);
>>> Is it documented that this is indeed a power supply failure ?
>>> What if the value is simply not reported ? "UNAVAILABLE" is not
>>> commonly associated with a "fault".
>>>
>>> Guenter
>>>
>> FAN_POWER_UNAVAILABLE signals that the power value is not supported.
>> Would it be more suitable to drop the fault attributes and just return -ENODATA in such a case?
>>
> There should be no fault attributes unless a real fault
> is reported, and if power reporting is not supported the
> hwmon_power_input attribute should not even be created.
>
> The same really applies to the fan speed atribute: If reading
> the fan speed is not supported, the attribute should not even
> exist.
>
> Guenter
>
I see, however it seems that some ACPI implementations also return a fan speed of 0xffffffff
to signal an error, so we cannot use this value to check if the BIOS supports fan speed
reporting.

I will send a v4 patch witch will drop the fault attributes. When encountering a fan speed
of 0xffffffff, returning -ENODATA should be ok i think.

Thanks,
Armin Wolf
diff mbox series

Patch

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 39ea5cfa8326..61ca4afe83dc 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -77,6 +77,7 @@  obj-$(CONFIG_ACPI_TINY_POWER_BUTTON)	+= tiny-power-button.o
 obj-$(CONFIG_ACPI_FAN)		+= fan.o
 fan-objs			:= fan_core.o
 fan-objs			+= fan_attr.o
+fan-$(CONFIG_HWMON)		+= fan_hwmon.o

 obj-$(CONFIG_ACPI_VIDEO)	+= video.o
 obj-$(CONFIG_ACPI_TAD)		+= acpi_tad.o
diff --git a/drivers/acpi/fan.h b/drivers/acpi/fan.h
index f89d19c922dc..db25a3898af7 100644
--- a/drivers/acpi/fan.h
+++ b/drivers/acpi/fan.h
@@ -10,6 +10,8 @@ 
 #ifndef _ACPI_FAN_H_
 #define _ACPI_FAN_H_

+#include <linux/kconfig.h>
+
 #define ACPI_FAN_DEVICE_IDS	\
 	{"INT3404", }, /* Fan */ \
 	{"INTC1044", }, /* Fan for Tiger Lake generation */ \
@@ -57,4 +59,11 @@  struct acpi_fan {
 int acpi_fan_get_fst(struct acpi_device *device, struct acpi_fan_fst *fst);
 int acpi_fan_create_attributes(struct acpi_device *device);
 void acpi_fan_delete_attributes(struct acpi_device *device);
+
+#if IS_REACHABLE(CONFIG_HWMON)
+int devm_acpi_fan_create_hwmon(struct acpi_device *device);
+#else
+static inline int devm_acpi_fan_create_hwmon(struct acpi_device *device) { return 0; };
+#endif
+
 #endif
diff --git a/drivers/acpi/fan_core.c b/drivers/acpi/fan_core.c
index ff72e4ef8738..7cea4495f19b 100644
--- a/drivers/acpi/fan_core.c
+++ b/drivers/acpi/fan_core.c
@@ -336,6 +336,10 @@  static int acpi_fan_probe(struct platform_device *pdev)
 		if (result)
 			return result;

+		result = devm_acpi_fan_create_hwmon(device);
+		if (result)
+			return result;
+
 		result = acpi_fan_create_attributes(device);
 		if (result)
 			return result;
diff --git a/drivers/acpi/fan_hwmon.c b/drivers/acpi/fan_hwmon.c
new file mode 100644
index 000000000000..57216ba872db
--- /dev/null
+++ b/drivers/acpi/fan_hwmon.c
@@ -0,0 +1,148 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * fan_hwmon.c - hwmon interface for the ACPI Fan driver
+ *
+ * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de>
+ */
+
+#include <linux/acpi.h>
+#include <linux/hwmon.h>
+#include <linux/limits.h>
+#include <linux/units.h>
+
+#include "fan.h"
+
+/* Returned when the ACPI fan does not support speed reporting */
+#define FAN_SPEED_UNAVAILABLE	0xffffffff
+#define FAN_POWER_UNAVAILABLE	0xffffffff
+
+static struct acpi_fan_fps *acpi_fan_get_current_fps(struct acpi_fan *fan, u64 control)
+{
+	int i;
+
+	for (i = 0; i < fan->fps_count; i++) {
+		if (fan->fps[i].control == control)
+			return &fan->fps[i];
+	}
+
+	return NULL;
+}
+
+static umode_t acpi_fan_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
+				   int channel)
+{
+	return 0444;
+}
+
+static int acpi_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
+			 long *val)
+{
+	struct acpi_device *adev = dev_get_drvdata(dev);
+	struct acpi_fan *fan = acpi_driver_data(adev);
+	struct acpi_fan_fps *fps;
+	struct acpi_fan_fst fst;
+	int ret;
+
+	ret = acpi_fan_get_fst(adev, &fst);
+	if (ret < 0)
+		return ret;
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			if (fst.speed == FAN_SPEED_UNAVAILABLE)
+				return -ENODATA;
+
+			if (fst.speed > LONG_MAX)
+				return -EOVERFLOW;
+
+			*val = fst.speed;
+			return 0;
+		case hwmon_fan_target:
+			fps = acpi_fan_get_current_fps(fan, fst.control);
+			if (!fps)
+				return -ENODATA;
+
+			*val = fps->speed;
+			return 0;
+		case hwmon_fan_fault:
+			*val = (fst.speed == FAN_SPEED_UNAVAILABLE);
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_power:
+		fps = acpi_fan_get_current_fps(fan, fst.control);
+		if (!fps)
+			return -ENODATA;
+
+		switch (attr) {
+		case hwmon_power_input:
+			if (fps->power == FAN_POWER_UNAVAILABLE)
+				return -ENODATA;
+
+			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
+				return -EOVERFLOW;
+
+			*val = fps->power * MICROWATT_PER_MILLIWATT;
+			return 0;
+		case hwmon_power_fault:
+			*val = (fps->power == FAN_POWER_UNAVAILABLE);
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops acpi_fan_ops = {
+	.is_visible = acpi_fan_is_visible,
+	.read = acpi_fan_read,
+};
+
+static const struct hwmon_channel_info * const acpi_fan_info[] = {
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET |  HWMON_F_FAULT),
+	HWMON_CHANNEL_INFO(power, HWMON_P_INPUT | HWMON_P_FAULT),
+	NULL
+};
+
+static const struct hwmon_chip_info acpi_fan_chip_info = {
+	.ops = &acpi_fan_ops,
+	.info = acpi_fan_info,
+};
+
+static const struct hwmon_channel_info * const acpi_fan_fine_grain_info[] = {
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT),
+	NULL
+};
+
+static const struct hwmon_chip_info acpi_fan_fine_grain_chip_info = {
+	.ops = &acpi_fan_ops,
+	.info = acpi_fan_fine_grain_info,
+};
+
+int devm_acpi_fan_create_hwmon(struct acpi_device *device)
+{
+	struct acpi_fan *fan = acpi_driver_data(device);
+	const struct hwmon_chip_info *info;
+	struct device *hdev;
+
+	/* When in fine grain control mode, not every fan control value
+	 * has an associated fan performance state.
+	 */
+	if (fan->fif.fine_grain_ctrl)
+		info = &acpi_fan_fine_grain_chip_info;
+	else
+		info = &acpi_fan_chip_info;
+
+	hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", device, info, NULL);
+
+	return PTR_ERR_OR_ZERO(hdev);
+}