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Message-ID: <b839f83f-c8c7-4fa8-8597-bdde1b40168a@roeck-us.net>
Date: Wed, 24 Jan 2024 22:54:07 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>, groeck7@...il.com,
sudeep.holla@....com, cristian.marussi@....com, jdelvare@...e.com
Cc: linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
Peng Fan <peng.fan@....com>
Subject: Re: [PATCH V3] hwmon: scmi-hwmon: implement change_mode for thermal
zones
On 1/24/24 22:44, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
>
> The thermal sensors maybe disabled before kernel boot, so add change_mode
> for thermal zones to support configuring the thermal sensor to enabled
> state. If reading the temperature when the sensor is disabled, there will
> be error reported.
>
> The cost is an extra config_get all to SCMI firmware to get the status
> of the thermal sensor. No function level impact.
>
> Reviewed-by: Cristian Marussi <cristian.marussi@....com>
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>
> V3:
> Update commit log to show it only applys to thermal
> Add comments in code
> Add R-b from Cristian
>
You didn't address my question regarding the behavior of hwmon
attributes if a sensor is disabled.
> Guenter, I Cced linux@...ck-us.net when sending V1/V2
> Let me Cc Guenter Roeck <groeck7@...il.com> in V3, hope you not mind
>
This time I received it twice ;-).
> V2:
> Use SCMI_SENS_CFG_IS_ENABLED & clear BIT[31:9] before update config(Thanks Cristian)
>
> drivers/hwmon/scmi-hwmon.c | 39 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
> index 364199b332c0..af2267fea5f0 100644
> --- a/drivers/hwmon/scmi-hwmon.c
> +++ b/drivers/hwmon/scmi-hwmon.c
> @@ -151,7 +151,46 @@ 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;
> +
> + /*
> + * Per SENSOR_CONFIG_SET sensor_config description:
> + * BIT[31:11] should be set to 0 if the sensor update interval does
> + * not need to be updated, so clear them.
> + * And SENSOR_CONFIG_GET does not return round up/down, so also clear
> + * BIT[10:9] round up/down.
What does "clear" mean ? Is it going to round up ? Round down ? And why would it
be necessary to clear those bits if SENSOR_CONFIG_GET does not return the
current setting in the first place ?
Thanks,
Guenter
> + */
> + 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);
> +}
> +
> static const struct thermal_zone_device_ops scmi_hwmon_thermal_ops = {
> + .change_mode = scmi_hwmon_thermal_change_mode,
> .get_temp = scmi_hwmon_thermal_get_temp,
> };
>
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