Re: [PATCH V2] hwmon: scmi-hwmon: implement change_mode

[Cristian Marussi <cristian.marussi@arm.com>]

On Tue, Jan 23, 2024 at 11:05:26PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> The sensor maybe disabled before kernel boot, so add change_mode
> to support configuring the sensor to enabled state.
> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---

In general LGTM.
It would be better clearly explaining in the commit message that this
change is around HWMON thermal zones and also add a comment down below
to justify why we have decided to clear out those config bits.

> 
> V2:
>  Use SCMI_SENS_CFG_IS_ENABLED & clear BIT[31:9] before update config(Thanks Cristian)
> 
>  drivers/hwmon/scmi-hwmon.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
> index 364199b332c0..913acd1b137b 100644
> --- a/drivers/hwmon/scmi-hwmon.c
> +++ b/drivers/hwmon/scmi-hwmon.c
> @@ -151,7 +151,39 @@ static int scmi_hwmon_thermal_get_temp(struct thermal_zone_device *tz,
>  	return ret;
>  }
>  
> +static int scmi_hwmon_thermal_change_mode(struct thermal_zone_device *tz,
> +					  enum thermal_device_mode new_mode)
> +{
> +	int ret;
> +	u32 config;
> +	enum thermal_device_mode cur_mode = THERMAL_DEVICE_DISABLED;
> +	struct scmi_thermal_sensor *th_sensor = thermal_zone_device_priv(tz);
> +
> +	ret = sensor_ops->config_get(th_sensor->ph, th_sensor->info->id,
> +				     &config);
> +	if (ret)
> +		return ret;
> +
> +	if (SCMI_SENS_CFG_IS_ENABLED(config))
> +		cur_mode = THERMAL_DEVICE_ENABLED;
> +
> +	if (cur_mode == new_mode)
> +		return 0;
> +

This config bits_clearing is worth an explanation in a comment (like we
did in the mail thread...)

> +	config &= ~(SCMI_SENS_CFG_UPDATE_SECS_MASK |
> +		    SCMI_SENS_CFG_UPDATE_EXP_MASK |
> +		    SCMI_SENS_CFG_ROUND_MASK);
> +	if (new_mode == THERMAL_DEVICE_ENABLED)
> +		config |= SCMI_SENS_CFG_SENSOR_ENABLED_MASK;
> +	else
> +		config &= ~SCMI_SENS_CFG_SENSOR_ENABLED_MASK;
> +
> +	return sensor_ops->config_set(th_sensor->ph, th_sensor->info->id,
> +				      config);
> +}
> +

Other than this,

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Thanks,
Cristian