linux-kernel - Re: [PATCH v3 6/6] platform/x86: ayaneo-ec: Add suspend hook

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Message-ID: <83b004ce-b34e-41a4-b35d-1f24056ac60a@gmx.de>
Date: Sun, 2 Nov 2025 19:35:12 +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 v3 6/6] platform/x86: ayaneo-ec: Add suspend hook

Am 31.10.25 um 17:36 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.

Please update the patch description.

>
> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> ---
>   drivers/platform/x86/ayaneo-ec.c | 73 ++++++++++++++++++++++++++++++++
>   1 file changed, 73 insertions(+)
>
> diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
> index 9548e3d22093..e1ad5968d3b4 100644
> --- a/drivers/platform/x86/ayaneo-ec.c
> +++ b/drivers/platform/x86/ayaneo-ec.c
> @@ -41,6 +41,8 @@
>   #define AYANEO_MODULE_LEFT	BIT(0)
>   #define AYANEO_MODULE_RIGHT	BIT(1)
>   
> +#define AYANEO_CACHE_LEN	1
> +
>   struct ayaneo_ec_quirk {
>   	bool has_fan_control;
>   	bool has_charge_control;
> @@ -51,6 +53,9 @@ struct ayaneo_ec_platform_data {
>   	struct platform_device *pdev;
>   	struct ayaneo_ec_quirk *quirks;
>   	struct acpi_battery_hook battery_hook;
> +
> +	bool restore_charge_limit;
> +	bool restore_pwm;
>   };
>   
>   static const struct ayaneo_ec_quirk quirk_fan = {
> @@ -207,10 +212,14 @@ 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 = platform_get_drvdata(
> +		to_platform_device(dev));
> +	int ret;
>   	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,
> @@ -224,6 +233,15 @@ 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;

I suspect that you need to use a mutex to protect the restore sequence.

Thanks,
Armin Wolf

> +			}
>   			return ec_write(AYANEO_PWM_REG, (val * 100) / 255);
>   		default:
>   			break;
> @@ -474,10 +492,65 @@ 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,
>   	},
>   	.probe = ayaneo_ec_probe,
>   };