Re: [PATCH v6 6/7] hwmon: Add Nuvoton NCT6694 HWMON support

[Vincent Mailhol <mailhol.vincent@wanadoo.fr>]

On 23/01/2025 at 18:11, Ming Yu wrote:
> This driver supports Hardware monitor functionality for NCT6694 MFD
> device based on USB interface.
> 
> Signed-off-by: Ming Yu <a0282524688@gmail.com>
> ---

(...)

> +static int nct6694_temp_write(struct device *dev, u32 attr, int channel,
> +			      long val)
> +{
> +	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
> +	struct nct6694_cmd_header cmd_hd;
> +	unsigned char temp_hyst;
> +	signed char temp_max;
> +	int ret;
> +
> +	guard(mutex)(&data->lock);
> +
> +	switch (attr) {
> +	case hwmon_temp_enable:
> +		if (val == 0)
> +			data->hwmon_en.tin_en[channel / 8] &= ~BIT(channel % 8);
> +		else if (val == 1)
> +			data->hwmon_en.tin_en[channel / 8] |= BIT(channel % 8);
> +		else
> +			return -EINVAL;
> +
> +		cmd_hd = (struct nct6694_cmd_header) {
> +			.mod = NCT6694_HWMON_MOD,
> +			.cmd = NCT6694_HWMON_CONTROL,
> +			.sel = NCT6694_HWMON_CONTROL_SEL,
> +			.len = cpu_to_le16(sizeof(data->hwmon_en))
> +		};
> +
> +		return nct6694_write_msg(data->nct6694, &cmd_hd,
> +					 &data->hwmon_en);
> +	case hwmon_temp_max:
> +		cmd_hd = (struct nct6694_cmd_header) {
> +			.mod = NCT6694_HWMON_MOD,
> +			.cmd = NCT6694_HWMON_ALARM,
> +			.sel = NCT6694_HWMON_ALARM_SEL,
> +			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
> +		};
> +		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
> +				       &data->msg->hwmon_alarm);
> +		if (ret)
> +			return ret;
> +
> +		val = clamp_val(val, -127000, 127000);
> +		data->msg->hwmon_alarm.tin_cfg[channel].hl = temp_to_reg(val);
> +
> +		return nct6694_write_msg(data->nct6694, &cmd_hd,
> +					 &data->msg->hwmon_alarm);
> +	case hwmon_temp_max_hyst:
> +		cmd_hd = (struct nct6694_cmd_header) {
> +			.mod = NCT6694_HWMON_MOD,
> +			.cmd = NCT6694_HWMON_ALARM,
> +			.sel = NCT6694_HWMON_ALARM_SEL,
> +			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
> +		};
> +		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
> +				       &data->msg->hwmon_alarm);
> +
> +		val = clamp_val(val, -127000, 127000);
> +		temp_max = data->msg->hwmon_alarm.tin_cfg[channel].hl;
> +		temp_hyst = temp_max - temp_to_reg(val);
> +		temp_hyst = clamp_val(temp_hyst, 0, 7);

temp_hyst is unsigned. It can not be smaller than zero. No need for
clamp(), using min here is sufficient.

> +		data->msg->hwmon_alarm.tin_cfg[channel].hyst =
> +			(data->msg->hwmon_alarm.tin_cfg[channel].hyst & ~NCT6694_TIN_HYST_MASK) |
> +			FIELD_PREP(NCT6694_TIN_HYST_MASK, temp_hyst);
> +
> +		return nct6694_write_msg(data->nct6694, &cmd_hd,
> +					 &data->msg->hwmon_alarm);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}

(...)

Yours sincerely,
Vincent Mailhol