Re: [PATCH v1 1/3] drivers/platform: lenovo-t14s-ec: Add hwmon support for temperatures and fan speed

[Konrad Dybcio]

On 6/24/26 11:08 PM, Daniel Lezcano wrote:
> Expose the Lenovo ThinkPad T14s EC environmental sensors through
> the hwmon subsystem.
> 
> The driver now registers a hwmon device providing access to six EC
> temperature sensors corresponding to the SoC, keyboard area, base
> cover, PMIC/charging circuitry, QTM module and SSD. Sensor labels
> are exported to allow user space to identify each measurement.
> 
> Additionally, expose the system fan speed by reading the fan RPM
> registers from the embedded controller.
> 
> This allows standard monitoring tools such as lm-sensors to report
> platform temperatures and fan speed.
> 
> Signed-off-by: Daniel Lezcano daniel.lezcano@xxxxxxxxxxxxxxxx
> ---

[...]

> +	case hwmon_fan:
> +		if (attr == hwmon_fan_input) {
> +			int lsb, msb;
> +			ret = t14s_ec_read(ec, T14S_EC_FAN_RPM_LSB, &lsb);
> +			if (ret)
> +				return ret;
> +
> +			ret = t14s_ec_read(ec, T14S_EC_FAN_RPM_MSB, &msb);
> +			if (ret)
> +				return ret;
> +
> +			*val = 0;
> +			*val = lsb + (msb << 8);

'+' looks funny here.. although t14s_ec_read() only reads a
single byte and assigns a u8 value to the u32 that's being passed
to it, so it never *actually* breaks..
 
[...]

> +static const struct hwmon_channel_info *t14s_ec_hwmon_info[] = {
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT | HWMON_T_LABEL,
> +			   HWMON_T_INPUT | HWMON_T_LABEL,
> +			   HWMON_T_INPUT | HWMON_T_LABEL,
> +			   HWMON_T_INPUT | HWMON_T_LABEL,
> +			   HWMON_T_INPUT | HWMON_T_LABEL,
> +			   HWMON_T_INPUT | HWMON_T_LABEL),
> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
> +	NULL
> +};
> +
> +static const struct hwmon_chip_info t14s_ec_chip_info = {
> +	.ops = &t14s_ec_hwmon_ops,
> +	.info = t14s_ec_hwmon_info,
> +};
> +
> +static int t14s_ec_hwmon_probe(struct t14s_ec *ec)
> +{
> +	struct device *dev;
> +	struct t14s_ec_hwmon_sys_thermx sys_thermx[] = {
> +		{ T14S_EC_SYS_THERM0, "soc" },
> +		{ T14S_EC_SYS_THERM1, "keyboard" },
> +		{ T14S_EC_SYS_THERM2, "base" },
> +		{ T14S_EC_SYS_THERM3, "pmbm" },
> +		{ T14S_EC_SYS_THERM6, "qtm" },
> +		{ T14S_EC_SYS_THERM7, "ssd" },

Makes one wonder what happened to THERM4/5 - may they be dedicated to
the 5G modem, perhaps?

Konrad