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Date: Wed, 22 May 2024 22:02:26 +0200
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Subject: Re: [PATCH v8] ACPI: fan: Add hwmon support
From: Armin Wolf <W_Armin@gmx.de>
To: mlj@danelec.com, rafael.j.wysocki@intel.com, lenb@kernel.org
Cc: jdelvare@suse.com, andy.shevchenko@gmail.com, linux@roeck-us.net,
 linux@weissschuh.net, ilpo.jarvinen@linux.intel.com,
 linux-acpi@vger.kernel.org, linux-hwmon@vger.kernel.org,
 linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org
References: <20240510201242.3886-1-W_Armin@gmx.de>
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Am 10.05.24 um 22:12 schrieb Armin Wolf:

> Currently, the driver does only support a custom sysfs
> interface 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".
>
> Reviewed-by: Andy Shevchenko <andy@kernel.org>
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Hi,

what is the current status of this?

Thanks,
Armin Wolf

> ---
> Tested witha custom ACPI SSDT, available here:
> https://github.com/Wer-Wolf/acpi-fan-ssdt
>
> Changes since v7:
> - add Reviewed-by tag
> - spelling fixes
> - add missing types.h include
>
> Changes since v6:
> - add "hwmon" to the names of functions and variables
> related to hwmon
> - replace -ENODATA with -EIO/-ENODEV
>
> Changes since v5:
> - fix coding style issues
> - replace double break with return
> - add missing includes
>
> Changes since v4:
> - fix spelling issues
> - check power values for overflow condition too
>
> Changes since v3:
> - drop fault attrs
> - rework initialization
>
> 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
> ---
>   drivers/acpi/Makefile    |   1 +
>   drivers/acpi/fan.h       |   9 +++
>   drivers/acpi/fan_core.c  |   4 +
>   drivers/acpi/fan_hwmon.c | 170 +++++++++++++++++++++++++++++++++++++++
>   4 files changed, 184 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..bd0d31a398fa
> --- /dev/null
> +++ b/drivers/acpi/fan_hwmon.c
> @@ -0,0 +1,170 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * hwmon interface for the ACPI Fan driver.
> + *
> + * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/limits.h>
> +#include <linux/types.h>
> +#include <linux/units.h>
> +
> +#include "fan.h"
> +
> +/* Returned when the ACPI fan does not support speed reporting */
> +#define FAN_SPEED_UNAVAILABLE	U32_MAX
> +#define FAN_POWER_UNAVAILABLE	U32_MAX
> +
> +static struct acpi_fan_fps *acpi_fan_get_current_fps(struct acpi_fan *fan, u64 control)
> +{
> +	unsigned 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_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
> +					 u32 attr, int channel)
> +{
> +	const struct acpi_fan *fan = drvdata;
> +	unsigned int i;
> +
> +	switch (type) {
> +	case hwmon_fan:
> +		switch (attr) {
> +		case hwmon_fan_input:
> +			return 0444;
> +		case hwmon_fan_target:
> +			/*
> +			 * When in fine grain control mode, not every fan control value
> +			 * has an associated fan performance state.
> +			 */
> +			if (fan->fif.fine_grain_ctrl)
> +				return 0;
> +
> +			return 0444;
> +		default:
> +			return 0;
> +		}
> +	case hwmon_power:
> +		switch (attr) {
> +		case hwmon_power_input:
> +			/*
> +			 * When in fine grain control mode, not every fan control value
> +			 * has an associated fan performance state.
> +			 */
> +			if (fan->fif.fine_grain_ctrl)
> +				return 0;
> +
> +			/*
> +			 * When all fan performance states contain no valid power data,
> +			 * when the associated attribute should not be created.
> +			 */
> +			for (i = 0; i < fan->fps_count; i++) {
> +				if (fan->fps[i].power != FAN_POWER_UNAVAILABLE)
> +					return 0444;
> +			}
> +
> +			return 0;
> +		default:
> +			return 0;
> +		}
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static int acpi_fan_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> +			       int channel, long *val)
> +{
> +	struct acpi_device *adev = to_acpi_device(dev->parent);
> +	struct acpi_fan *fan = dev_get_drvdata(dev);
> +	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 -ENODEV;
> +
> +			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 -EIO;
> +
> +			if (fps->speed > LONG_MAX)
> +				return -EOVERFLOW;
> +
> +			*val = fps->speed;
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	case hwmon_power:
> +		switch (attr) {
> +		case hwmon_power_input:
> +			fps = acpi_fan_get_current_fps(fan, fst.control);
> +			if (!fps)
> +				return -EIO;
> +
> +			if (fps->power == FAN_POWER_UNAVAILABLE)
> +				return -ENODEV;
> +
> +			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
> +				return -EOVERFLOW;
> +
> +			*val = fps->power * MICROWATT_PER_MILLIWATT;
> +			return 0;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static const struct hwmon_ops acpi_fan_hwmon_ops = {
> +	.is_visible = acpi_fan_hwmon_is_visible,
> +	.read = acpi_fan_hwmon_read,
> +};
> +
> +static const struct hwmon_channel_info * const acpi_fan_hwmon_info[] = {
> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET),
> +	HWMON_CHANNEL_INFO(power, HWMON_P_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info acpi_fan_hwmon_chip_info = {
> +	.ops = &acpi_fan_hwmon_ops,
> +	.info = acpi_fan_hwmon_info,
> +};
> +
> +int devm_acpi_fan_create_hwmon(struct acpi_device *device)
> +{
> +	struct acpi_fan *fan = acpi_driver_data(device);
> +	struct device *hdev;
> +
> +	hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", fan,
> +						    &acpi_fan_hwmon_chip_info, NULL);
> +	return PTR_ERR_OR_ZERO(hdev);
> +}
> --
> 2.39.2
>
>