linux-kernel - Re: [PATCH v5 6/6] platform/x86: ayaneo-ec: Add suspend hook

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Message-ID: <c329d8c7-1dfd-4168-a267-cc7fcc66aeb7@gmx.de>
Date: Sun, 16 Nov 2025 17:05:31 +0100
From: Armin Wolf <W_Armin@....de>
To: Antheas Kapenekakis <lkml@...heas.dev>,
 platform-driver-x86@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
 Hans de Goede <hansg@...nel.org>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 Derek John Clark <derekjohn.clark@...il.com>,
 Joaquín Ignacio Aramendía <samsagax@...il.com>,
 Jean Delvare <jdelvare@...e.com>, Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v5 6/6] platform/x86: ayaneo-ec: Add suspend hook

Am 13.11.25 um 22:22 schrieb Antheas Kapenekakis:

> The Ayaneo EC resets after hibernation, losing the charge control state.
> Add a small PM hook to restore this state on hibernation resume.
>
> The fan speed is also lost during hibernation, but since hibernation
> failures are common with this class of devices, setting a low fan speed
> when the userspace program controlling the fan will potentially not
> take over could cause the device to overheat, so it is not restored.
>
> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> ---
>   drivers/platform/x86/ayaneo-ec.c | 84 +++++++++++++++++++++++++++++++-
>   1 file changed, 83 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
> index 814f7f028710..3f40429acbd4 100644
> --- a/drivers/platform/x86/ayaneo-ec.c
> +++ b/drivers/platform/x86/ayaneo-ec.c
> @@ -52,6 +52,11 @@ struct ayaneo_ec_platform_data {
>   	struct platform_device *pdev;
>   	struct ayaneo_ec_quirk *quirks;
>   	struct acpi_battery_hook battery_hook;
> +
> +	// Protects access to restore_pwm
> +	struct mutex hwmon_lock;
> +	bool restore_charge_limit;
> +	bool restore_pwm;
>   };
>   
>   static const struct ayaneo_ec_quirk quirk_fan = {
> @@ -208,10 +213,16 @@ static int ayaneo_ec_read(struct device *dev, enum hwmon_sensor_types type,
>   static int ayaneo_ec_write(struct device *dev, enum hwmon_sensor_types type,
>   			   u32 attr, int channel, long val)
>   {
> +	struct ayaneo_ec_platform_data *data = dev_get_drvdata(dev);
> +	int ret;
> +
> +	guard(mutex)(&data->hwmon_lock);
> +
>   	switch (type) {
>   	case hwmon_pwm:
>   		switch (attr) {
>   		case hwmon_pwm_enable:
> +			data->restore_pwm = false;
>   			switch (val) {
>   			case 1:
>   				return ec_write(AYANEO_PWM_ENABLE_REG,
> @@ -225,6 +236,17 @@ static int ayaneo_ec_write(struct device *dev, enum hwmon_sensor_types type,
>   		case hwmon_pwm_input:
>   			if (val < 0 || val > 255)
>   				return -EINVAL;
> +			if (data->restore_pwm) {
> +				/*
> +				 * Defer restoring PWM control to after
> +				 * userspace resumes successfully
> +				 */
> +				ret = ec_write(AYANEO_PWM_ENABLE_REG,
> +					       AYANEO_PWM_MODE_MANUAL);
> +				if (ret)
> +					return ret;
> +				data->restore_pwm = false;
> +			}
>   			return ec_write(AYANEO_PWM_REG, (val * 100) / 255);
>   		default:
>   			break;
> @@ -454,11 +476,14 @@ static int ayaneo_ec_probe(struct platform_device *pdev)
>   
>   	data->pdev = pdev;
>   	data->quirks = dmi_entry->driver_data;
> +	ret = devm_mutex_init(&pdev->dev, &data->hwmon_lock);
> +	if (ret)
> +		return ret;
>   	platform_set_drvdata(pdev, data);
>   
>   	if (data->quirks->has_fan_control) {
>   		hwdev = devm_hwmon_device_register_with_info(&pdev->dev,
> -			"ayaneo_ec", NULL, &ayaneo_ec_chip_info, NULL);
> +			"ayaneo_ec", data, &ayaneo_ec_chip_info, NULL);
>   		if (IS_ERR(hwdev))
>   			return PTR_ERR(hwdev);
>   	}
> @@ -475,10 +500,67 @@ static int ayaneo_ec_probe(struct platform_device *pdev)
>   	return 0;
>   }
>   
> +static int ayaneo_freeze(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ayaneo_ec_platform_data *data = platform_get_drvdata(pdev);
> +	int ret;
> +	u8 tmp;
> +
> +	if (data->quirks->has_charge_control) {
> +		ret = ec_read(AYANEO_CHARGE_REG, &tmp);
> +		if (ret)
> +			return ret;
> +
> +		data->restore_charge_limit = tmp == AYANEO_CHARGE_VAL_INHIBIT;
> +	}
> +
> +	if (data->quirks->has_fan_control) {
> +		ret = ec_read(AYANEO_PWM_ENABLE_REG, &tmp);
> +		if (ret)
> +			return ret;
> +
> +		data->restore_pwm = tmp == AYANEO_PWM_MODE_MANUAL;
> +
> +		/*
> +		 * Release the fan when entering hibernation to avoid
> +		 * overheating if hibernation fails and hangs.
> +		 */
> +		if (data->restore_pwm) {
> +			ret = ec_write(AYANEO_PWM_ENABLE_REG, AYANEO_PWM_MODE_AUTO);
> +			if (ret)
> +				return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int ayaneo_restore(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ayaneo_ec_platform_data *data = platform_get_drvdata(pdev);
> +	int ret;
> +
> +	if (data->quirks->has_charge_control && data->restore_charge_limit) {
> +		ret = ec_write(AYANEO_CHARGE_REG, AYANEO_CHARGE_VAL_INHIBIT);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ayaneo_pm_ops = {
> +	.freeze = ayaneo_freeze,
> +	.restore = ayaneo_restore,
> +};
> +
>   static struct platform_driver ayaneo_platform_driver = {
>   	.driver = {
>   		.name = "ayaneo-ec",
>   		.dev_groups = ayaneo_ec_groups,
> +		.pm = &ayaneo_pm_ops,

Maybe you should use pm_sleep_ptr() here. With that being fixed:
Reviewed-by: Armin Wolf <W_Armin@....de>

>   	},
>   	.probe = ayaneo_ec_probe,
>   };