iio: accel: adxl345: Pass function pointer to core

Provide a way for bus specific pre-configuration by adding a function
pointer argument to the driver core's probe() function, and keep
the driver core implementation bus independent.

In case NULL was passed, a regmap_write() shall initialize all bits of
the data_format register, else regmap_update() is used. In this way
spi and i2c are covered.
Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Link: https://lore.kernel.org/r/20240401194906.56810-6-l.rubusch@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/adxl345.h

@@ -60,6 +60,7 @@ struct adxl345_chip_info {
 	int uscale;
 };
 
-int adxl345_core_probe(struct device *dev, struct regmap *regmap);
+int adxl345_core_probe(struct device *dev, struct regmap *regmap,
+		       int (*setup)(struct device*, struct regmap*));
 
 #endif /* _ADXL345_H_ */

drivers/iio/accel/adxl345_core.c

@@ -168,7 +168,8 @@ static void adxl345_powerdown(void *regmap)
 	regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
 }
 
-int adxl345_core_probe(struct device *dev, struct regmap *regmap)
+int adxl345_core_probe(struct device *dev, struct regmap *regmap,
+		       int (*setup)(struct device*, struct regmap*))
 {
 	struct adxl345_data *data;
 	struct iio_dev *indio_dev;
@@ -179,6 +180,29 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
 					 ADXL345_DATA_FORMAT_SELF_TEST);
 	int ret;
 
+	if (setup) {
+		/* Perform optional initial bus specific configuration */
+		ret = setup(dev, regmap);
+		if (ret)
+			return ret;
+
+		/* Enable full-resolution mode */
+		ret = regmap_update_bits(regmap, ADXL345_REG_DATA_FORMAT,
+					 data_format_mask,
+					 ADXL345_DATA_FORMAT_FULL_RES);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to set data range\n");
+
+	} else {
+		/* Enable full-resolution mode (init all data_format bits) */
+		ret = regmap_write(regmap, ADXL345_REG_DATA_FORMAT,
+				   ADXL345_DATA_FORMAT_FULL_RES);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to set data range\n");
+	}
+
 	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "Error reading device ID\n");
@@ -203,12 +227,6 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
 	indio_dev->channels = adxl345_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
 
-	/* Enable full-resolution mode */
-	ret = regmap_update_bits(regmap, ADXL345_REG_DATA_FORMAT,
-			data_format_mask, ADXL345_DATA_FORMAT_FULL_RES);
-	if (ret)
-		return dev_err_probe(dev, ret, "Failed to set data range\n");
-
 	/* Enable measurement mode */
 	ret = adxl345_powerup(data->regmap);
 	if (ret < 0)

drivers/iio/accel/adxl345_i2c.c

@@ -27,7 +27,7 @@ static int adxl345_i2c_probe(struct i2c_client *client)
 	if (IS_ERR(regmap))
 		return dev_err_probe(&client->dev, PTR_ERR(regmap), "Error initializing regmap\n");
 
-	return adxl345_core_probe(&client->dev, regmap);
+	return adxl345_core_probe(&client->dev, regmap, NULL);
 }
 
 static const struct adxl345_chip_info adxl345_i2c_info = {

drivers/iio/accel/adxl345_spi.c

@@ -33,7 +33,7 @@ static int adxl345_spi_probe(struct spi_device *spi)
 	if (IS_ERR(regmap))
 		return dev_err_probe(&spi->dev, PTR_ERR(regmap), "Error initializing regmap\n");
 
-	return adxl345_core_probe(&spi->dev, regmap);
+	return adxl345_core_probe(&spi->dev, regmap, NULL);
 }
 
 static const struct adxl345_chip_info adxl345_spi_info = {