Re: [PATCH v4 04/10] hwmon: (tmp421) support disabling channels from DT

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

On 10/12/21 2:27 AM, Krzysztof Adamski wrote:
> The previous patch introduced per channel subnodes in DT that let us
> specify some channel specific properties. This built a ground for easily
> disabling individual channels of the sensor that may not be connected to
> any external diode and thus are not returning any meaningful data.
> 
> This patch adds support for parsing the "status" property of channels DT
> subnodes and makes sure the -ENODATA is returned when disabled channels
> value is read.
> 
> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>

For my reference:

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   drivers/hwmon/tmp421.c | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
> index ab64d9825ca4..fffffd671e34 100644
> --- a/drivers/hwmon/tmp421.c
> +++ b/drivers/hwmon/tmp421.c
> @@ -89,6 +89,7 @@ MODULE_DEVICE_TABLE(of, tmp421_of_match);
>   
>   struct tmp421_channel {
>   	const char *label;
> +	bool enabled;
>   	s16 temp;
>   };
>   
> @@ -170,6 +171,9 @@ static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
>   	if (ret)
>   		return ret;
>   
> +	if (!tmp421->channel[channel].enabled)
> +		return -ENODATA;
> +
>   	switch (attr) {
>   	case hwmon_temp_input:
>   		*val = temp_from_raw(tmp421->channel[channel].temp,
> @@ -323,6 +327,8 @@ static int tmp421_probe_child_from_dt(struct i2c_client *client,
>   	if (data->channel[i].label)
>   		data->temp_config[i] |= HWMON_T_LABEL;
>   
> +	data->channel[i].enabled = of_device_is_available(child);
> +
>   	return 0;
>   }
>   
> @@ -371,8 +377,10 @@ static int tmp421_probe(struct i2c_client *client)
>   	if (err)
>   		return err;
>   
> -	for (i = 0; i < data->channels; i++)
> +	for (i = 0; i < data->channels; i++) {
>   		data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
> +		data->channel[i].enabled = true;
> +	}
>   
>   	err = tmp421_probe_from_dt(client, data);
>   	if (err)
>