Re: [PATCH 2/2] hwmon: lm75: Add support for label

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

On Wed, Mar 11, 2026 at 12:58:08PM +0200, Flaviu Nistor wrote:
> Add support for label sysfs attribute similar to other hwmon devices.
> This is particularly useful for systems with multiple sensors on the
> same board, where identifying individual sensors is much easier since
> labels can be defined via device tree.
> 
> Signed-off-by: Flaviu Nistor <flaviu.nistor@gmail.com>
> ---
>  drivers/hwmon/lm75.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index eda93a8c23c9..66178ac63e4f 100644
> --- a/drivers/hwmon/lm75.c
> +++ b/drivers/hwmon/lm75.c
> @@ -108,6 +108,7 @@ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
>  #define PCT2075_REG_IDLE	0x04
>  
>  struct lm75_data {
> +	const char *label;
>  	struct regmap			*regmap;
>  	u16				orig_conf;
>  	u8				resolution;	/* In bits, 9 to 16 */
> @@ -363,6 +364,16 @@ static irqreturn_t lm75_alarm_handler(int irq, void *private)
>  	return IRQ_HANDLED;
>  }
>  
> +static int lm75_read_string(struct device *dev, enum hwmon_sensor_types type,
> +			    u32 attr, int channel, const char **str)
> +{
> +	struct lm75_data *data = dev_get_drvdata(dev);
> +
> +	*str = data->label;
> +
> +	return 0;
> +}
> +
>  static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
>  		     u32 attr, int channel, long *val)
>  {
> @@ -534,6 +545,9 @@ static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
>  		switch (attr) {
>  		case hwmon_temp_input:
>  			return 0444;
> +		case hwmon_temp_label:
> +		/* Hide label node if label is not provided */
> +			return (config_data->label) ? 0444 : 0;

Unnecessary ()

>  		case hwmon_temp_max:
>  		case hwmon_temp_max_hyst:
>  			return 0644;
> @@ -553,13 +567,14 @@ static const struct hwmon_channel_info * const lm75_info[] = {
>  	HWMON_CHANNEL_INFO(chip,
>  			   HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
>  	HWMON_CHANNEL_INFO(temp,
> -			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST |
> +			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_MAX | HWMON_T_MAX_HYST |
>  			   HWMON_T_ALARM),
>  	NULL
>  };
>  
>  static const struct hwmon_ops lm75_hwmon_ops = {
>  	.is_visible = lm75_is_visible,
> +	.read_string = lm75_read_string,
>  	.read = lm75_read,
>  	.write = lm75_write,
>  };
> @@ -721,6 +736,9 @@ static int lm75_generic_probe(struct device *dev, const char *name,
>  	/* needed by custom regmap callbacks */
>  	dev_set_drvdata(dev, data);
>  
> +	/* Save the connected input label if available */
> +	of_property_read_string(dev->of_node, "label", &data->label);

Please use device_property_read_string().

Thanks,
Guenter

> +
>  	data->kind = kind;
>  	data->regmap = regmap;
>