linux-kernel - Re: [PATCH v2 6/6] platform/x86: ayaneo-ec: Add suspend hook

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Message-ID: <de1f9cd3-183e-7b01-72aa-23fa4d30334e@linux.intel.com>
Date: Wed, 15 Oct 2025 12:11:40 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Antheas Kapenekakis <lkml@...heas.dev>
cc: platform-driver-x86@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>, 
    linux-hwmon@...r.kernel.org, Hans de Goede <hansg@...nel.org>, 
    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 v2 6/6] platform/x86: ayaneo-ec: Add suspend hook

On Wed, 15 Oct 2025, Antheas Kapenekakis wrote:

> 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 | 42 ++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
> index 73e9dd39c703..8529f6f8dc69 100644
> --- a/drivers/platform/x86/ayaneo-ec.c
> +++ b/drivers/platform/x86/ayaneo-ec.c
> @@ -37,6 +37,8 @@
>  #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;
> @@ -47,6 +49,8 @@ struct ayaneo_ec_platform_data {
>  	struct platform_device *pdev;
>  	struct ayaneo_ec_quirk *quirks;
>  	struct acpi_battery_hook battery_hook;
> +
> +	u8 cache[AYANEO_CACHE_LEN];
>  };
>  
>  static const struct ayaneo_ec_quirk quirk_fan = {
> @@ -464,10 +468,48 @@ 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, i = 0;
> +
> +	if (data->quirks->has_charge_control) {
> +		ret = ec_read(AYANEO_CHARGE_REG, &data->cache[i]);
> +		if (ret)
> +			return ret;
> +		i++;

What is this for?

> +	}
> +
> +	return 0;
> +}
> +
> +static int ayaneo_thaw(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct ayaneo_ec_platform_data *data = platform_get_drvdata(pdev);
> +	int ret, i = 0;
> +
> +	if (data->quirks->has_charge_control) {
> +		ret = ec_write(AYANEO_CHARGE_REG, data->cache[i]);
> +		if (ret)
> +			return ret;
> +		i++;

Same question here.

> +	}
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops ayaneo_pm_ops = {
> +	.freeze = ayaneo_freeze,
> +	.thaw = ayaneo_thaw,
> +};
> +
>  static struct platform_driver ayaneo_platform_driver = {
>  	.driver = {
>  		.name = "ayaneo-ec",
>  		.dev_groups = ayaneo_ec_groups,
> +		.pm = &ayaneo_pm_ops,
>  	},
>  	.probe = ayaneo_ec_probe,
>  };
> 

-- 
 i.