Re: [PATCH v2] iio: temperature: ltc2983: pass leak detector type explicitly

[nuno . sa]

On Fri, Oct 02, 2026 at 11:44:50AM -0500, Carlos Casadiego via B4 Relay wrote:
> From: Carlos Casadiego <cdcp206@xxxxxxxxx>
> 
> __ltc2983_custom_sensor_new() uses propname both to select the firmware
> property to read and to determine whether the custom sensor is a leak
> detector.
> 
> Pass this information explicitly from the caller instead of deriving
> the sensor type from the firmware property name. This keeps propname
> limited to identifying the property and preserves the existing
> conversion behavior.
> 
> As a side effect, this also avoids the -Wstring-compare warning reported
> by the kernel test robot for callers where GCC can determine that the
> property name cannot match "adi,custom-leak-detector".
> 
> Fixes: 3dd0c048409e ("iio: temperature: ltc2983: Add support for ADT7604")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202609120045.OxEsKLIn-lkp@xxxxxxxxx/
> Signed-off-by: Carlos Casadiego <cdcp206@xxxxxxxxx>
> ---

Looks to me this is the one to apply. So:

Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>

> Changes in v2:
> - Reframe the change around passing the leak detector type explicitly,
>   with the compiler warning as a side effect.
> - Drop const qualifiers from bool parameters as suggested by Andy
>   Shevchenko.
> - Link to v1: https://patch.msgid.link/20260929-iio-ltc2983-fix-string-compare-v1-1-d67d612d6ddd@xxxxxxxxx
> 
> To: Nuno Sá <nuno.sa@xxxxxxxxxx>
> To: Jonathan Cameron <jic23@xxxxxxxxxx>
> To: David Lechner <dlechner@xxxxxxxxxxxx>
> To: Andy Shevchenko <andy@xxxxxxxxxx>
> To: Liviu Stan <liviu.stan@xxxxxxxxxx>
> Cc: linux-iio@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
>  drivers/iio/temperature/ltc2983.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
> index 6efb5252a773..6abaf64c8498 100644
> --- a/drivers/iio/temperature/ltc2983.c
> +++ b/drivers/iio/temperature/ltc2983.c
> @@ -471,8 +471,9 @@ static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
>  
>  static struct ltc2983_custom_sensor *
>  __ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle *fn,
> -			    const char *propname, const bool is_steinhart,
> -			    const u32 resolution, const bool has_signed)
> +			    const char *propname, bool is_steinhart,
> +			    const u32 resolution, bool has_signed,
> +			    bool is_leak_detector)
>  {
>  	struct ltc2983_custom_sensor *new_custom;
>  	struct device *dev = &st->spi->dev;
> @@ -545,7 +546,7 @@ __ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle
>  			 * to µK so __convert_to_raw() produces the correct hardware
>  			 * encoding: P + 273.15 K.
>  			 */
> -			if ((index % 2) != 0 && !strcmp(propname, "adi,custom-leak-detector"))
> +			if ((index % 2) != 0 && is_leak_detector)
>  				temp = temp * 1000000 + 273150000;
>  
>  			if ((index % 2) != 0)
> @@ -836,7 +837,7 @@ ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data
>  
>  		thermo->custom = __ltc2983_custom_sensor_new(st, child,
>  							     propname, false,
> -							     16384, true);
> +							     16384, true, false);
>  		if (IS_ERR(thermo->custom))
>  			return ERR_CAST(thermo->custom);
>  	}
> @@ -950,7 +951,8 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
>  	if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
>  		rtd->custom = __ltc2983_custom_sensor_new(st, child,
>  							  "adi,custom-rtd",
> -							  false, 2048, false);
> +							  false, 2048, false,
> +							  false);
>  		if (IS_ERR(rtd->custom))
>  			return ERR_CAST(rtd->custom);
>  	}
> @@ -1068,7 +1070,7 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
>  		thermistor->custom = __ltc2983_custom_sensor_new(st, child,
>  								 propname,
>  								 steinhart,
> -								 64, false);
> +								 64, false, false);
>  		if (IS_ERR(thermistor->custom))
>  			return ERR_CAST(thermistor->custom);
>  	}
> @@ -1184,7 +1186,7 @@ ltc2983_copper_trace_new(const struct fwnode_handle *child, struct ltc2983_data
>  						 "adi,custom-copper-trace is required for >1 ohm copper trace\n");
>  
>  		ct->custom = __ltc2983_custom_sensor_new(st, child, "adi,custom-copper-trace",
> -							 false, 2048, false);
> +							 false, 2048, false, false);
>  		if (IS_ERR(ct->custom))
>  			return ERR_CAST(ct->custom);
>  
> @@ -1275,7 +1277,7 @@ ltc2983_leak_detector_new(const struct fwnode_handle *child, struct ltc2983_data
>  					 "adi,custom-leak-detector is required for leak detectors\n");
>  
>  	ld->custom = __ltc2983_custom_sensor_new(st, child, "adi,custom-leak-detector",
> -						 false, 16, false);
> +						 false, 16, false, true);
>  	if (IS_ERR(ld->custom))
>  		return ERR_CAST(ld->custom);
>  
> @@ -1488,7 +1490,7 @@ static struct ltc2983_sensor *ltc2983_temp_new(struct fwnode_handle *child,
>  					 sensor->chan);
>  
>  	temp->custom = __ltc2983_custom_sensor_new(st, child, "adi,custom-temp",
> -						   false, 4096, true);
> +						   false, 4096, true, false);
>  	if (IS_ERR(temp->custom))
>  		return ERR_CAST(temp->custom);
>  
> 
> ---
> base-commit: d2f2868d2f487b418f68db2ef5bd7cf41722ee68
> change-id: 20260929-iio-ltc2983-fix-string-compare-c919244f019d
> 
> Best regards,
> --  
> Carlos Casadiego <cdcp206@xxxxxxxxx>
> 
>