linux-kernel - Re: [PATCH v6 11/14] platform/x86: oxpec: Adhere to sysfs-class-hwmon and enable pwm on 2

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Message-ID: <96d19837-167a-43d6-93ea-cd24844cff7f@t-8ch.de>
Date: Sat, 22 Mar 2025 09:23:49 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Antheas Kapenekakis <lkml@...heas.dev>
Cc: platform-driver-x86@...r.kernel.org, linux-hwmon@...r.kernel.org, 
	linux-doc@...r.kernel.org, linux-pm@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>, 
	Jean Delvare <jdelvare@...e.com>, Jonathan Corbet <corbet@....net>, 
	Joaquin Ignacio Aramendia <samsagax@...il.com>, Derek J Clark <derekjohn.clark@...il.com>, 
	Kevin Greenberg <kdgreenberg234@...tonmail.com>, Joshua Tam <csinaction@...me>, 
	Parth Menon <parthasarathymenon@...il.com>, Eileen <eileen@...-netbook.com>, linux-kernel@...r.kernel.org, 
	sre@...nel.org, ilpo.jarvinen@...ux.intel.com, hdegoede@...hat.com, 
	mario.limonciello@....com
Subject: Re: [PATCH v6 11/14] platform/x86: oxpec: Adhere to
 sysfs-class-hwmon and enable pwm on 2

On 2025-03-19 18:55:06+0100, Antheas Kapenekakis wrote:
> Currently, the driver does not adhere to the sysfs-class-hwmon
> specification: 0 is used for auto fan control and 1 is used for manual
> control. However, it is expected that 0 sets the fan to full speed,
> 1 sets the fan to manual, and then 2 is used for automatic control.
> 
> Therefore, change the sysfs API to reflect this and enable pwm on 2.
> 
> As we are breaking the ABI for this driver, rename oxpec to oxp_ec,
> reflecting the naming convention used by other drivers, to allow for
> a smooth migration in current userspace programs.

Where is the renaming being done?

> Closes: https://lore.kernel.org/linux-hwmon/20241027174836.8588-1-derekjohn.clark@gmail.com/
> Reviewed-by: Derek J. Clark <derekjohn.clark@...il.com>
> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> ---
>  drivers/platform/x86/oxpec.c | 35 ++++++++++++++++++++++++++++++++---
>  1 file changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/oxpec.c b/drivers/platform/x86/oxpec.c
> index e84afc5f53379..680fa537babf6 100644
> --- a/drivers/platform/x86/oxpec.c
> +++ b/drivers/platform/x86/oxpec.c
> @@ -731,7 +731,27 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
>  		case hwmon_pwm_input:
>  			return oxp_pwm_input_read(val);
>  		case hwmon_pwm_enable:
> -			return oxp_pwm_read(val);
> +			ret = oxp_pwm_read(val);
> +			if (ret)
> +				return ret;
> +
> +			/* Check for auto and return 2 */
> +			if (!*val) {
> +				*val = 2;
> +				return 0;
> +			}
> +
> +			/* Return 0 if at full fan speed, 1 otherwise */
> +			ret = oxp_pwm_fan_speed(val);
> +			if (ret)
> +				return ret;
> +
> +			if (*val == 255)
> +				*val = 0;
> +			else
> +				*val = 1;
> +
> +			return 0;
>  		default:
>  			break;
>  		}
> @@ -745,15 +765,24 @@ static int oxp_platform_read(struct device *dev, enum hwmon_sensor_types type,
>  static int oxp_platform_write(struct device *dev, enum hwmon_sensor_types type,
>  			      u32 attr, int channel, long val)
>  {
> +	int ret;
> +
>  	switch (type) {
>  	case hwmon_pwm:
>  		switch (attr) {
>  		case hwmon_pwm_enable:
>  			if (val == 1)
>  				return oxp_pwm_enable();
> -			else if (val == 0)
> +			else if (val == 2)
>  				return oxp_pwm_disable();
> -			return -EINVAL;
> +			else if (val != 0)
> +				return -EINVAL;
> +
> +			/* Enable PWM and set to max speed */
> +			ret = oxp_pwm_enable();
> +			if (ret)
> +				return ret;
> +			return oxp_pwm_input_write(255);
>  		case hwmon_pwm_input:
>  			return oxp_pwm_input_write(val);
>  		default:
> -- 
> 2.48.1
>