[PATCH v4 6/9] iio: temperature: ltc2983: Use fwnode_property_present() for optional properties
From: Liviu Stan
Date: Mon May 25 2026 - 12:44:40 EST
Checking fwnode_property_read_u32() return value with if (!ret)
silently swallows meaningful error codes when a property is present
but malformed. Use fwnode_property_present() first so that absence
uses the default while a present but unreadable property returns
a proper error.
Signed-off-by: Liviu Stan <liviu.stan@xxxxxxxxxx>
---
Changes in v4:
- No changes
drivers/iio/temperature/ltc2983.c | 84 +++++++++++++++++++++----------
1 file changed, 58 insertions(+), 26 deletions(-)
diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index fc904c0a42b4..130ab7fddc2f 100644
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -668,8 +668,14 @@ ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data
if (fwnode_property_read_bool(child, "adi,single-ended"))
thermo->sensor_config = LTC2983_THERMOCOUPLE_SGL(1);
- ret = fwnode_property_read_u32(child, "adi,sensor-oc-current-microamp", &oc_current);
- if (!ret) {
+ if (fwnode_property_present(child, "adi,sensor-oc-current-microamp")) {
+ ret = fwnode_property_read_u32(child,
+ "adi,sensor-oc-current-microamp",
+ &oc_current);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,sensor-oc-current-microamp\n");
+
switch (oc_current) {
case 10:
thermo->sensor_config |=
@@ -759,8 +765,12 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
return dev_err_ptr_probe(dev, ret,
"Property reg must be given\n");
- ret = fwnode_property_read_u32(child, "adi,number-of-wires", &n_wires);
- if (!ret) {
+ if (fwnode_property_present(child, "adi,number-of-wires")) {
+ ret = fwnode_property_read_u32(child, "adi,number-of-wires", &n_wires);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,number-of-wires\n");
+
switch (n_wires) {
case 2:
rtd->sensor_config = LTC2983_RTD_N_WIRES(0);
@@ -842,12 +852,13 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
rtd->sensor.fault_handler = ltc2983_common_fault_handler;
rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
- ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
- &excitation_current);
- if (ret) {
- /* default to 5uA */
- rtd->excitation_current = 1;
- } else {
+ if (fwnode_property_present(child, "adi,excitation-current-microamp")) {
+ ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
+ &excitation_current);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,excitation-current-microamp\n");
+
switch (excitation_current) {
case 5:
rtd->excitation_current = 0x01;
@@ -878,9 +889,17 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
"Invalid value for excitation current(%u)\n",
excitation_current);
}
+ } else {
+ /* default to 5uA */
+ rtd->excitation_current = 1;
}
- fwnode_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
+ if (fwnode_property_present(child, "adi,rtd-curve")) {
+ ret = fwnode_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,rtd-curve\n");
+ }
return &rtd->sensor;
}
@@ -950,17 +969,13 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
thermistor->sensor.fault_handler = ltc2983_common_fault_handler;
thermistor->sensor.assign_chan = ltc2983_thermistor_assign_chan;
- ret = fwnode_property_read_u32(child, "adi,excitation-current-nanoamp",
- &excitation_current);
- if (ret) {
- /* Auto range is not allowed for custom sensors */
- if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
- /* default to 1uA */
- thermistor->excitation_current = 0x03;
- else
- /* default to auto-range */
- thermistor->excitation_current = 0x0c;
- } else {
+ if (fwnode_property_present(child, "adi,excitation-current-nanoamp")) {
+ ret = fwnode_property_read_u32(child, "adi,excitation-current-nanoamp",
+ &excitation_current);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,excitation-current-nanoamp\n");
+
switch (excitation_current) {
case 0:
/* auto range */
@@ -1008,6 +1023,14 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
"Invalid value for excitation current(%u)\n",
excitation_current);
}
+ } else {
+ /* Auto range is not allowed for custom sensors */
+ if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
+ /* default to 1uA */
+ thermistor->excitation_current = 0x03;
+ else
+ /* default to auto-range */
+ thermistor->excitation_current = 0x0c;
}
return &thermistor->sensor;
@@ -1046,9 +1069,13 @@ ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *
diode->sensor.fault_handler = ltc2983_common_fault_handler;
diode->sensor.assign_chan = ltc2983_diode_assign_chan;
- ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
- &excitation_current);
- if (!ret) {
+ if (fwnode_property_present(child, "adi,excitation-current-microamp")) {
+ ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
+ &excitation_current);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,excitation-current-microamp\n");
+
switch (excitation_current) {
case 10:
diode->excitation_current = 0x00;
@@ -1069,7 +1096,12 @@ ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *
}
}
- fwnode_property_read_u32(child, "adi,ideal-factor-value", &temp);
+ if (fwnode_property_present(child, "adi,ideal-factor-value")) {
+ ret = fwnode_property_read_u32(child, "adi,ideal-factor-value", &temp);
+ if (ret)
+ return dev_err_ptr_probe(dev, ret,
+ "Failed to read adi,ideal-factor-value\n");
+ }
/* 2^20 resolution */
diode->ideal_factor_value = __convert_to_raw(temp, 1048576);
--
2.43.0