[PATCH v3 0/3] iio: temperature: ltc2983: small improvements

[PATCH v3 0/3] iio: temperature: ltc2983: small improvements

[Nuno Sa via B4 Relay]

Hi Jonathan,

The quick v3 is only to fix the error in the bindings patch...

v1:
 * https://lore.kernel.org/all/20240222-ltc2983-misc-improv-v1-0-cf7d4457e98c@analog.com/

v2:
 * https://lore.kernel.org/all/20240229-ltc2983-misc-improv-v2-0-cc6f03da2529@analog.com/

v3:
 - Patch 2
   * Added vdd-supply to the dts example;

---
Nuno Sa (3):
      iio: temperature: ltc2983: convert to dev_err_probe()
      dt-bindings: iio: temperature: ltc2983: document power supply
      iio: temperature: ltc2983: support vdd regulator

 .../bindings/iio/temperature/adi,ltc2983.yaml      |   4 +
 drivers/iio/temperature/ltc2983.c                  | 267 ++++++++++-----------
 2 files changed, 131 insertions(+), 140 deletions(-)
---
base-commit: 74744b27ba8cb8c265263aa0ff0693350a8cbc19
change-id: 20240227-ltc2983-misc-improv-d9c4a3819b1f
--

Thanks!
- Nuno Sá

[PATCH v3 1/3] iio: temperature: ltc2983: convert to dev_err_probe()

[Nuno Sa via B4 Relay]

From: Nuno Sa <nuno.sa@analog.com>

Use dev_err_probe() in the probe() path. While at it, made some simple
improvements:
 * Declare a struct device *dev helper. This also makes the style more
   consistent (some places the helper was used and not in other places);
 * Explicitly included the err.h and errno.h headers;
 * Removed an useless else if();
 * Removed some unnecessary line breaks.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
 drivers/iio/temperature/ltc2983.c | 262 ++++++++++++++++++--------------------
 1 file changed, 122 insertions(+), 140 deletions(-)

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index 3c4524d57b8e..592887097117 100644
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -8,6 +8,8 @@
 #include <linux/bitfield.h>
 #include <linux/completion.h>
 #include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/iio/iio.h>
 #include <linux/interrupt.h>
@@ -206,6 +208,13 @@ enum {
 #define to_temp(_sensor) \
 		container_of(_sensor, struct ltc2983_temp, sensor)
 
+/* Helper macro for returning error pointers in probe() paths. */
+#define ltc2983_errp_probe(dev, ret, fmt, ...)	({			\
+	int ___ret = dev_err_probe(dev, ret, fmt, ##__VA_ARGS__);	\
+									\
+	ERR_PTR(___ret);						\
+})
+
 struct ltc2983_chip_info {
 	const char *name;
 	unsigned int max_channels_nr;
@@ -657,10 +666,11 @@ ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data
 			 const struct ltc2983_sensor *sensor)
 {
 	struct ltc2983_thermocouple *thermo;
+	struct device *dev = &st->spi->dev;
 	u32 oc_current;
 	int ret;
 
-	thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo), GFP_KERNEL);
+	thermo = devm_kzalloc(dev, sizeof(*thermo), GFP_KERNEL);
 	if (!thermo)
 		return ERR_PTR(-ENOMEM);
 
@@ -687,21 +697,19 @@ ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data
 					LTC2983_THERMOCOUPLE_OC_CURR(3);
 			break;
 		default:
-			dev_err(&st->spi->dev,
-				"Invalid open circuit current:%u", oc_current);
-			return ERR_PTR(-EINVAL);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid open circuit current:%u",
+						  oc_current);
 		}
 
 		thermo->sensor_config |= LTC2983_THERMOCOUPLE_OC_CHECK(1);
 	}
 	/* validate channel index */
 	if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK) &&
-	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev,
-			"Invalid chann:%d for differential thermocouple",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chann:%d for differential thermocouple",
+					  sensor->chan);
 
 	struct fwnode_handle *ref __free(fwnode_handle) =
 		fwnode_find_reference(child, "adi,cold-junction-handle", 0);
@@ -709,14 +717,13 @@ ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data
 		ref = NULL;
 	} else {
 		ret = fwnode_property_read_u32(ref, "reg", &thermo->cold_junction_chan);
-		if (ret) {
+		if (ret)
 			/*
 			 * This would be catched later but we can just return
 			 * the error right away.
 			 */
-			dev_err(&st->spi->dev, "Property reg must be given\n");
-			return ERR_PTR(ret);
-		}
+			return ltc2983_errp_probe(dev, ret,
+						  "Property reg must be given\n");
 	}
 
 	/* check custom sensor */
@@ -752,16 +759,14 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
 
 	struct fwnode_handle *ref __free(fwnode_handle) =
 		fwnode_find_reference(child, "adi,rsense-handle", 0);
-	if (IS_ERR(ref)) {
-		dev_err(dev, "Property adi,rsense-handle missing or invalid");
-		return ERR_CAST(ref);
-	}
+	if (IS_ERR(ref))
+		return ltc2983_errp_probe(dev, PTR_ERR(ref),
+					  "Property adi,rsense-handle missing or invalid");
 
 	ret = fwnode_property_read_u32(ref, "reg", &rtd->r_sense_chan);
-	if (ret) {
-		dev_err(dev, "Property reg must be given\n");
-		return ERR_PTR(ret);
-	}
+	if (ret)
+		return ltc2983_errp_probe(dev, ret,
+					  "Property reg must be given\n");
 
 	ret = fwnode_property_read_u32(child, "adi,number-of-wires", &n_wires);
 	if (!ret) {
@@ -780,19 +785,19 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
 			rtd->sensor_config = LTC2983_RTD_N_WIRES(3);
 			break;
 		default:
-			dev_err(dev, "Invalid number of wires:%u\n", n_wires);
-			return ERR_PTR(-EINVAL);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid number of wires:%u\n",
+						  n_wires);
 		}
 	}
 
 	if (fwnode_property_read_bool(child, "adi,rsense-share")) {
 		/* Current rotation is only available with rsense sharing */
 		if (fwnode_property_read_bool(child, "adi,current-rotate")) {
-			if (n_wires == 2 || n_wires == 3) {
-				dev_err(dev,
-					"Rotation not allowed for 2/3 Wire RTDs");
-				return ERR_PTR(-EINVAL);
-			}
+			if (n_wires == 2 || n_wires == 3)
+				return ltc2983_errp_probe(dev, -EINVAL,
+							  "Rotation not allowed for 2/3 Wire RTDs");
+
 			rtd->sensor_config |= LTC2983_RTD_C_ROTATE(1);
 		} else {
 			rtd->sensor_config |= LTC2983_RTD_R_SHARE(1);
@@ -815,29 +820,22 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
 
 		if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
 		     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
-		    (rtd->r_sense_chan <=  min)) {
+		    (rtd->r_sense_chan <=  min))
 			/* kelvin rsense*/
-			dev_err(dev,
-				"Invalid rsense chann:%d to use in kelvin rsense",
-				rtd->r_sense_chan);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid rsense chann:%d to use in kelvin rsense",
+						  rtd->r_sense_chan);
 
-			return ERR_PTR(-EINVAL);
-		}
-
-		if (sensor->chan < min || sensor->chan > max) {
-			dev_err(dev, "Invalid chann:%d for the rtd config",
-				sensor->chan);
-
-			return ERR_PTR(-EINVAL);
-		}
+		if (sensor->chan < min || sensor->chan > max)
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid chann:%d for the rtd config",
+						  sensor->chan);
 	} else {
 		/* same as differential case */
-		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-			dev_err(&st->spi->dev,
-				"Invalid chann:%d for RTD", sensor->chan);
-
-			return ERR_PTR(-EINVAL);
-		}
+		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid chann:%d for RTD",
+						  sensor->chan);
 	}
 
 	/* check custom sensor */
@@ -885,10 +883,9 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
 			rtd->excitation_current = 0x08;
 			break;
 		default:
-			dev_err(&st->spi->dev,
-				"Invalid value for excitation current(%u)",
-				excitation_current);
-			return ERR_PTR(-EINVAL);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid value for excitation current(%u)",
+						  excitation_current);
 		}
 	}
 
@@ -912,16 +909,14 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
 
 	struct fwnode_handle *ref __free(fwnode_handle) =
 		fwnode_find_reference(child, "adi,rsense-handle", 0);
-	if (IS_ERR(ref)) {
-		dev_err(dev, "Property adi,rsense-handle missing or invalid");
-		return ERR_CAST(ref);
-	}
+	if (IS_ERR(ref))
+		return ltc2983_errp_probe(dev, PTR_ERR(ref),
+					  "Property adi,rsense-handle missing or invalid");
 
 	ret = fwnode_property_read_u32(ref, "reg", &thermistor->r_sense_chan);
-	if (ret) {
-		dev_err(dev, "rsense channel must be configured...\n");
-		return ERR_PTR(ret);
-	}
+	if (ret)
+		return ltc2983_errp_probe(dev, ret,
+					  "rsense channel must be configured...\n");
 
 	if (fwnode_property_read_bool(child, "adi,single-ended")) {
 		thermistor->sensor_config = LTC2983_THERMISTOR_SGL(1);
@@ -936,12 +931,10 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
 	}
 	/* validate channel index */
 	if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK) &&
-	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev,
-			"Invalid chann:%d for differential thermistor",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chann:%d for differential thermistor",
+					  sensor->chan);
 
 	/* check custom sensor */
 	if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
@@ -980,12 +973,10 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
 		switch (excitation_current) {
 		case 0:
 			/* auto range */
-			if (sensor->type >=
-			    LTC2983_SENSOR_THERMISTOR_STEINHART) {
-				dev_err(&st->spi->dev,
-					"Auto Range not allowed for custom sensors\n");
-				return ERR_PTR(-EINVAL);
-			}
+			if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
+				return ltc2983_errp_probe(dev, -EINVAL,
+							  "Auto Range not allowed for custom sensors\n");
+
 			thermistor->excitation_current = 0x0c;
 			break;
 		case 250:
@@ -1022,10 +1013,9 @@ ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *s
 			thermistor->excitation_current = 0x0b;
 			break;
 		default:
-			dev_err(&st->spi->dev,
-				"Invalid value for excitation current(%u)",
-				excitation_current);
-			return ERR_PTR(-EINVAL);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid value for excitation current(%u)",
+						  excitation_current);
 		}
 	}
 
@@ -1036,11 +1026,12 @@ static struct ltc2983_sensor *
 ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *st,
 		  const struct ltc2983_sensor *sensor)
 {
+	struct device *dev = &st->spi->dev;
 	struct ltc2983_diode *diode;
 	u32 temp = 0, excitation_current = 0;
 	int ret;
 
-	diode = devm_kzalloc(&st->spi->dev, sizeof(*diode), GFP_KERNEL);
+	diode = devm_kzalloc(dev, sizeof(*diode), GFP_KERNEL);
 	if (!diode)
 		return ERR_PTR(-ENOMEM);
 
@@ -1055,12 +1046,11 @@ ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *
 
 	/* validate channel index */
 	if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
-	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev,
-			"Invalid chann:%d for differential thermistor",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chann:%d for differential thermistor",
+					  sensor->chan);
+
 	/* set common parameters */
 	diode->sensor.fault_handler = ltc2983_common_fault_handler;
 	diode->sensor.assign_chan = ltc2983_diode_assign_chan;
@@ -1082,10 +1072,9 @@ ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *
 			diode->excitation_current = 0x03;
 			break;
 		default:
-			dev_err(&st->spi->dev,
-				"Invalid value for excitation current(%u)",
-				excitation_current);
-			return ERR_PTR(-EINVAL);
+			return ltc2983_errp_probe(dev, -EINVAL,
+						  "Invalid value for excitation current(%u)",
+						  excitation_current);
 		}
 	}
 
@@ -1101,26 +1090,26 @@ static struct ltc2983_sensor *ltc2983_r_sense_new(struct fwnode_handle *child,
 					struct ltc2983_data *st,
 					const struct ltc2983_sensor *sensor)
 {
+	struct device *dev = &st->spi->dev;
 	struct ltc2983_rsense *rsense;
 	int ret;
 	u32 temp;
 
-	rsense = devm_kzalloc(&st->spi->dev, sizeof(*rsense), GFP_KERNEL);
+	rsense = devm_kzalloc(dev, sizeof(*rsense), GFP_KERNEL);
 	if (!rsense)
 		return ERR_PTR(-ENOMEM);
 
 	/* validate channel index */
-	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chann:%d for r_sense",
+					  sensor->chan);
 
 	ret = fwnode_property_read_u32(child, "adi,rsense-val-milli-ohms", &temp);
-	if (ret) {
-		dev_err(&st->spi->dev, "Property adi,rsense-val-milli-ohms missing\n");
-		return ERR_PTR(-EINVAL);
-	}
+	if (ret)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Property adi,rsense-val-milli-ohms missing\n");
+
 	/*
 	 * Times 1000 because we have milli-ohms and __convert_to_raw
 	 * expects scales of 1000000 which are used for all other
@@ -1139,21 +1128,21 @@ static struct ltc2983_sensor *ltc2983_adc_new(struct fwnode_handle *child,
 					 struct ltc2983_data *st,
 					 const struct ltc2983_sensor *sensor)
 {
+	struct device *dev = &st->spi->dev;
 	struct ltc2983_adc *adc;
 
-	adc = devm_kzalloc(&st->spi->dev, sizeof(*adc), GFP_KERNEL);
+	adc = devm_kzalloc(dev, sizeof(*adc), GFP_KERNEL);
 	if (!adc)
 		return ERR_PTR(-ENOMEM);
 
 	if (fwnode_property_read_bool(child, "adi,single-ended"))
 		adc->single_ended = true;
 
-	if (!adc->single_ended &&
-	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev, "Invalid chan:%d for differential adc\n",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	if (!adc->single_ended && sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chan:%d for differential adc\n",
+					  sensor->chan);
+
 	/* set common parameters */
 	adc->sensor.assign_chan = ltc2983_adc_assign_chan;
 	adc->sensor.fault_handler = ltc2983_common_fault_handler;
@@ -1165,21 +1154,20 @@ static struct ltc2983_sensor *ltc2983_temp_new(struct fwnode_handle *child,
 					       struct ltc2983_data *st,
 					       const struct ltc2983_sensor *sensor)
 {
+	struct device *dev = &st->spi->dev;
 	struct ltc2983_temp *temp;
 
-	temp = devm_kzalloc(&st->spi->dev, sizeof(*temp), GFP_KERNEL);
+	temp = devm_kzalloc(dev, sizeof(*temp), GFP_KERNEL);
 	if (!temp)
 		return ERR_PTR(-ENOMEM);
 
 	if (fwnode_property_read_bool(child, "adi,single-ended"))
 		temp->single_ended = true;
 
-	if (!temp->single_ended &&
-	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
-		dev_err(&st->spi->dev, "Invalid chan:%d for differential temp\n",
-			sensor->chan);
-		return ERR_PTR(-EINVAL);
-	}
+	if (!temp->single_ended && sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN)
+		return ltc2983_errp_probe(dev, -EINVAL,
+					  "Invalid chan:%d for differential temp\n",
+					  sensor->chan);
 
 	temp->custom = __ltc2983_custom_sensor_new(st, child, "adi,custom-temp",
 						   false, 4096, true);
@@ -1329,10 +1317,9 @@ static int ltc2983_parse_fw(struct ltc2983_data *st)
 	device_property_read_u32(dev, "adi,filter-notch-freq", &st->filter_notch_freq);
 
 	st->num_channels = device_get_child_node_count(dev);
-	if (!st->num_channels) {
-		dev_err(&st->spi->dev, "At least one channel must be given!");
-		return -EINVAL;
-	}
+	if (!st->num_channels)
+		return dev_err_probe(dev, -EINVAL,
+				     "At least one channel must be given!");
 
 	st->sensors = devm_kcalloc(dev, st->num_channels, sizeof(*st->sensors),
 				   GFP_KERNEL);
@@ -1419,6 +1406,7 @@ static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
 			      unsigned int wait_time, unsigned int status_reg,
 			      unsigned long status_fail_mask)
 {
+	struct device *dev = &st->spi->dev;
 	unsigned long time;
 	unsigned int val;
 	int ret;
@@ -1437,19 +1425,16 @@ static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
 
 	time = wait_for_completion_timeout(&st->completion,
 					   msecs_to_jiffies(wait_time));
-	if (!time) {
-		dev_err(&st->spi->dev, "EEPROM command timed out\n");
-		return -ETIMEDOUT;
-	}
+	if (!time)
+		return dev_err_probe(dev, -ETIMEDOUT, "EEPROM command timed out\n");
 
 	ret = regmap_read(st->regmap, status_reg, &val);
 	if (ret)
 		return ret;
 
-	if (val & status_fail_mask) {
-		dev_err(&st->spi->dev, "EEPROM command failed: 0x%02X\n", val);
-		return -EINVAL;
-	}
+	if (val & status_fail_mask)
+		return dev_err_probe(dev, -EINVAL,
+				     "EEPROM command failed: 0x%02X\n", val);
 
 	return 0;
 }
@@ -1457,16 +1442,15 @@ static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
 static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
 {
 	u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0, status;
+	struct device *dev = &st->spi->dev;
 	int ret;
 
 	/* make sure the device is up: start bit (7) is 0 and done bit (6) is 1 */
 	ret = regmap_read_poll_timeout(st->regmap, LTC2983_STATUS_REG, status,
 				       LTC2983_STATUS_UP(status) == 1, 25000,
 				       25000 * 10);
-	if (ret) {
-		dev_err(&st->spi->dev, "Device startup timed out\n");
-		return ret;
-	}
+	if (ret)
+		return dev_err_probe(dev, ret, "Device startup timed out\n");
 
 	ret = regmap_update_bits(st->regmap, LTC2983_GLOBAL_CONFIG_REG,
 				 LTC2983_NOTCH_FREQ_MASK,
@@ -1566,12 +1550,13 @@ static const struct  iio_info ltc2983_iio_info = {
 
 static int ltc2983_probe(struct spi_device *spi)
 {
+	struct device *dev = &spi->dev;
 	struct ltc2983_data *st;
 	struct iio_dev *indio_dev;
 	struct gpio_desc *gpio;
 	int ret;
 
-	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;
 
@@ -1582,10 +1567,9 @@ static int ltc2983_probe(struct spi_device *spi)
 		return -ENODEV;
 
 	st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
-	if (IS_ERR(st->regmap)) {
-		dev_err(&spi->dev, "Failed to initialize regmap\n");
-		return PTR_ERR(st->regmap);
-	}
+	if (IS_ERR(st->regmap))
+		return dev_err_probe(dev, PTR_ERR(st->regmap),
+				     "Failed to initialize regmap\n");
 
 	mutex_init(&st->lock);
 	init_completion(&st->completion);
@@ -1597,7 +1581,7 @@ static int ltc2983_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
-	gpio = devm_gpiod_get_optional(&st->spi->dev, "reset", GPIOD_OUT_HIGH);
+	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(gpio))
 		return PTR_ERR(gpio);
 
@@ -1607,7 +1591,7 @@ static int ltc2983_probe(struct spi_device *spi)
 		gpiod_set_value_cansleep(gpio, 0);
 	}
 
-	st->iio_chan = devm_kzalloc(&spi->dev,
+	st->iio_chan = devm_kzalloc(dev,
 				    st->iio_channels * sizeof(*st->iio_chan),
 				    GFP_KERNEL);
 	if (!st->iio_chan)
@@ -1617,12 +1601,10 @@ static int ltc2983_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
-	ret = devm_request_irq(&spi->dev, spi->irq, ltc2983_irq_handler,
+	ret = devm_request_irq(dev, spi->irq, ltc2983_irq_handler,
 			       IRQF_TRIGGER_RISING, st->info->name, st);
-	if (ret) {
-		dev_err(&spi->dev, "failed to request an irq, %d", ret);
-		return ret;
-	}
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request an irq\n");
 
 	if (st->info->has_eeprom) {
 		ret = ltc2983_eeprom_cmd(st, LTC2983_EEPROM_WRITE_CMD,
@@ -1639,7 +1621,7 @@ static int ltc2983_probe(struct spi_device *spi)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &ltc2983_iio_info;
 
-	return devm_iio_device_register(&spi->dev, indio_dev);
+	return devm_iio_device_register(dev, indio_dev);
 }
 
 static int ltc2983_resume(struct device *dev)

-- 
2.43.2

Re: [PATCH v3 1/3] iio: temperature: ltc2983: convert to dev_err_probe()

[Jonathan Cameron]

On Fri, 01 Mar 2024 18:14:50 +0100
Nuno Sa via B4 Relay <devnull+nuno.sa.analog.com@kernel.org> wrote:

> From: Nuno Sa <nuno.sa@analog.com>
> 
> Use dev_err_probe() in the probe() path. While at it, made some simple
> improvements:
>  * Declare a struct device *dev helper. This also makes the style more
>    consistent (some places the helper was used and not in other places);
>  * Explicitly included the err.h and errno.h headers;
>  * Removed an useless else if();
>  * Removed some unnecessary line breaks.
> 
> Signed-off-by: Nuno Sa <nuno.sa@analog.com>

I'd rather see a proposal for dev_errp_probe() than a local solution.
We can fallback to local solution if it doesn't meet with approval!

Not that many uses in IIO so far, but seems some potential elsewhere.
There are already a few return ERR_PTR(dev_err_probe()) cases in tree
for low hanging fruit + looks like scmi_iio could benefit as another case
in IIO.

> ---
>  drivers/iio/temperature/ltc2983.c | 262 ++++++++++++++++++--------------------
>  1 file changed, 122 insertions(+), 140 deletions(-)
> 
> diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
> index 3c4524d57b8e..592887097117 100644
> --- a/drivers/iio/temperature/ltc2983.c
> +++ b/drivers/iio/temperature/ltc2983.c
> @@ -8,6 +8,8 @@
>  #include <linux/bitfield.h>
>  #include <linux/completion.h>
>  #include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
>  #include <linux/kernel.h>
>  #include <linux/iio/iio.h>
>  #include <linux/interrupt.h>
> @@ -206,6 +208,13 @@ enum {
>  #define to_temp(_sensor) \
>  		container_of(_sensor, struct ltc2983_temp, sensor)
>  
> +/* Helper macro for returning error pointers in probe() paths. */
> +#define ltc2983_errp_probe(dev, ret, fmt, ...)	({			\
> +	int ___ret = dev_err_probe(dev, ret, fmt, ##__VA_ARGS__);	\
> +									\
> +	ERR_PTR(___ret);						\

Given it's all wrapped up in a macro, I'd avoid the need for the ___ to try
and prevent shadowing an existing variable by just going with
	ERR_PTR(dev_err_probe(dev, ret, fmt, ##__VA_ARGS__))
and no ({ complexities.

If you really need to use a local variable, just through the hoops to make it unique
like the cleanup.h macros do.

> +})
> +

Re: [PATCH v3 1/3] iio: temperature: ltc2983: convert to dev_err_probe()

[Nuno Sá]

On Sun, 2024-03-03 at 12:16 +0000, Jonathan Cameron wrote:
> On Fri, 01 Mar 2024 18:14:50 +0100
> Nuno Sa via B4 Relay <devnull+nuno.sa.analog.com@kernel.org> wrote:
> 
> > From: Nuno Sa <nuno.sa@analog.com>
> > 
> > Use dev_err_probe() in the probe() path. While at it, made some simple
> > improvements:
> >  * Declare a struct device *dev helper. This also makes the style more
> >    consistent (some places the helper was used and not in other places);
> >  * Explicitly included the err.h and errno.h headers;
> >  * Removed an useless else if();
> >  * Removed some unnecessary line breaks.
> > 
> > Signed-off-by: Nuno Sa <nuno.sa@analog.com>
> 
> I'd rather see a proposal for dev_errp_probe() than a local solution.
> We can fallback to local solution if it doesn't meet with approval!
> 

I was kind of expecting that already :). I'll propose that for device.h. I guess
a simple macro should be enough...

- Nuno Sá

[PATCH v3 2/3] dt-bindings: iio: temperature: ltc2983: document power supply

[Nuno Sa via B4 Relay]

From: Nuno Sa <nuno.sa@analog.com>

Add a property for the VDD power supply regulator.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
 Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
index dbb85135fd668..312febeeb3bba 100644
--- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
+++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
@@ -57,6 +57,8 @@ properties:
   interrupts:
     maxItems: 1
 
+  vdd-supply: true
+
   adi,mux-delay-config-us:
     description: |
       Extra delay prior to each conversion, in addition to the internal 1ms
@@ -460,6 +462,7 @@ required:
   - compatible
   - reg
   - interrupts
+  - vdd-supply
 
 additionalProperties: false
 
@@ -489,6 +492,7 @@ examples:
             #address-cells = <1>;
             #size-cells = <0>;
 
+            vdd-supply = <&supply>;
             interrupts = <20 IRQ_TYPE_EDGE_RISING>;
             interrupt-parent = <&gpio>;
 

-- 
2.43.2

Re: [PATCH v3 2/3] dt-bindings: iio: temperature: ltc2983: document power supply

[Krzysztof Kozlowski]

On 01/03/2024 18:14, Nuno Sa via B4 Relay wrote:
> From: Nuno Sa <nuno.sa@analog.com>
> 
> Add a property for the VDD power supply regulator.
> 
> Signed-off-by: Nuno Sa <nuno.sa@analog.com>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v3 3/3] iio: temperature: ltc2983: support vdd regulator

[Nuno Sa via B4 Relay]

From: Nuno Sa <nuno.sa@analog.com>

Add support for the power supply regulator.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
 drivers/iio/temperature/ltc2983.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index 592887097117..9fb547417536 100644
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
 
 #include <asm/byteorder.h>
@@ -1581,6 +1582,10 @@ static int ltc2983_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
+	ret = devm_regulator_get_enable(&spi->dev, "vdd");
+	if (ret)
+		return ret;
+
 	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(gpio))
 		return PTR_ERR(gpio);

-- 
2.43.2