Re: [PATCH v3 1/2] hwmon: (dell-smm) Add support for fanX_min, fanX_max and fanX_target

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Sep 27, 2021 at 12:10:43AM +0200, W_Armin@gmx.de wrote:
> From: Armin Wolf <W_Armin@gmx.de>
> 
> The nominal speed of each fan can be obtained with
> i8k_get_fan_nominal_speed(), however the result is not available
> from userspace.
> Change that by adding fanX_min, fanX_max and fanX_target attributes.
> All are RO since fan control happens over pwm.
> 
> Tested on a Dell Inspiron 3505 and a Dell Latitude C600.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> Reviewed-by: Pali Rohár <pali@kernel.org>

Applied.

Thanks,
Guenter

> ---
>  Documentation/hwmon/dell-smm-hwmon.rst |  3 ++
>  drivers/hwmon/dell-smm-hwmon.c         | 61 +++++++++++++++++++++++---
>  2 files changed, 58 insertions(+), 6 deletions(-)
> 
> --
> 2.20.1
> 
> diff --git a/Documentation/hwmon/dell-smm-hwmon.rst b/Documentation/hwmon/dell-smm-hwmon.rst
> index 3bf77a5df995..beec88491171 100644
> --- a/Documentation/hwmon/dell-smm-hwmon.rst
> +++ b/Documentation/hwmon/dell-smm-hwmon.rst
> @@ -34,6 +34,9 @@ Name				Perm	Description
>  =============================== ======= =======================================
>  fan[1-3]_input                  RO      Fan speed in RPM.
>  fan[1-3]_label                  RO      Fan label.
> +fan[1-3]_min                    RO      Minimal Fan speed in RPM
> +fan[1-3]_max                    RO      Maximal Fan speed in RPM
> +fan[1-3]_target                 RO      Expected Fan speed in RPM
>  pwm[1-3]                        RW      Control the fan PWM duty-cycle.
>  pwm1_enable                     WO      Enable or disable automatic BIOS fan
>                                          control (not supported on all laptops,
> diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
> index 774c1b0715d9..476f2a74bd8c 100644
> --- a/drivers/hwmon/dell-smm-hwmon.c
> +++ b/drivers/hwmon/dell-smm-hwmon.c
> @@ -76,6 +76,7 @@ struct dell_smm_data {
>  	int temp_type[DELL_SMM_NO_TEMP];
>  	bool fan[DELL_SMM_NO_FANS];
>  	int fan_type[DELL_SMM_NO_FANS];
> +	int *fan_nominal_speed[DELL_SMM_NO_FANS];
>  };
> 
>  MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
> @@ -673,6 +674,13 @@ static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types
>  			if (data->fan[channel] && !data->disallow_fan_type_call)
>  				return 0444;
> 
> +			break;
> +		case hwmon_fan_min:
> +		case hwmon_fan_max:
> +		case hwmon_fan_target:
> +			if (data->fan_nominal_speed[channel])
> +				return 0444;
> +
>  			break;
>  		default:
>  			break;
> @@ -740,6 +748,25 @@ static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 a
> 
>  			*val = ret;
> 
> +			return 0;
> +		case hwmon_fan_min:
> +			*val = data->fan_nominal_speed[channel][0];
> +
> +			return 0;
> +		case hwmon_fan_max:
> +			*val = data->fan_nominal_speed[channel][data->i8k_fan_max];
> +
> +			return 0;
> +		case hwmon_fan_target:
> +			ret = i8k_get_fan_status(data, channel);
> +			if (ret < 0)
> +				return ret;
> +
> +			if (ret > data->i8k_fan_max)
> +				ret = data->i8k_fan_max;
> +
> +			*val = data->fan_nominal_speed[channel][ret];
> +
>  			return 0;
>  		default:
>  			break;
> @@ -889,9 +916,12 @@ static const struct hwmon_channel_info *dell_smm_info[] = {
>  			   HWMON_T_INPUT | HWMON_T_LABEL
>  			   ),
>  	HWMON_CHANNEL_INFO(fan,
> -			   HWMON_F_INPUT | HWMON_F_LABEL,
> -			   HWMON_F_INPUT | HWMON_F_LABEL,
> -			   HWMON_F_INPUT | HWMON_F_LABEL
> +			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
> +			   HWMON_F_TARGET,
> +			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
> +			   HWMON_F_TARGET,
> +			   HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
> +			   HWMON_F_TARGET
>  			   ),
>  	HWMON_CHANNEL_INFO(pwm,
>  			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
> @@ -910,7 +940,7 @@ static int __init dell_smm_init_hwmon(struct device *dev)
>  {
>  	struct dell_smm_data *data = dev_get_drvdata(dev);
>  	struct device *dell_smm_hwmon_dev;
> -	int i, err;
> +	int i, state, err;
> 
>  	for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
>  		data->temp_type[i] = i8k_get_temp_type(i);
> @@ -926,8 +956,27 @@ static int __init dell_smm_init_hwmon(struct device *dev)
>  		err = i8k_get_fan_status(data, i);
>  		if (err < 0)
>  			err = i8k_get_fan_type(data, i);
> -		if (err >= 0)
> -			data->fan[i] = true;
> +
> +		if (err < 0)
> +			continue;
> +
> +		data->fan[i] = true;
> +		data->fan_nominal_speed[i] = devm_kmalloc_array(dev, data->i8k_fan_max + 1,
> +								sizeof(*data->fan_nominal_speed[i]),
> +								GFP_KERNEL);
> +		if (!data->fan_nominal_speed[i])
> +			continue;
> +
> +		for (state = 0; state <= data->i8k_fan_max; state++) {
> +			err = i8k_get_fan_nominal_speed(data, i, state);
> +			if (err < 0) {
> +				/* Mark nominal speed table as invalid in case of error */
> +				devm_kfree(dev, data->fan_nominal_speed[i]);
> +				data->fan_nominal_speed[i] = NULL;
> +				break;
> +			}
> +			data->fan_nominal_speed[i][state] = err;
> +		}
>  	}
> 
>  	dell_smm_hwmon_dev = devm_hwmon_device_register_with_info(dev, "dell_smm", data,