[PATCH] iio: temperature: ltc2983: avoid string comparison for leak detector

[Carlos Casadiego via B4 Relay]

From: Carlos Casadiego <cdcp206@xxxxxxxxx>

GCC can determine at compile time that propname cannot match
"adi,custom-leak-detector" when __ltc2983_custom_sensor_new() is
inlined for some callers, triggering a -Wstring-compare warning.

Pass an explicit flag for leak detectors instead of deriving the sensor
type from the firmware property name. This preserves the existing
conversion behavior and avoids the constant string comparison.

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>
---
 drivers/iio/temperature/ltc2983.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index 6efb5252a773..38c5e81f5f88 100644
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -472,7 +472,8 @@ 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 u32 resolution, const bool has_signed,
+			    const 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>