iio: temperature: ltc2983: Use fwnode_property_present() for optional properties

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@analog.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index fc904c0a42b46687434cec1c01b66084e6305bed..130ab7fddc2fe9e0abf9c51fc268209caf46fc59 100644 (file)
--- 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);