[PATCH v6 1/7] iio: accel: adxl345: Make data_range obsolete

[Lothar Rubusch <l.rubusch@gmail.com>]

Replace write() data_format by regmap_update_bits() to keep bus specific
pre-configuration which might have happened before on the same register.
The bus specific bits in data_format register then need to be masked out,

Remove the data_range field from the struct adxl345_data, because it is
not used anymore.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 8bd30a23e..f4dec5ff1 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -37,7 +37,11 @@
 #define ADXL345_POWER_CTL_MEASURE	BIT(3)
 #define ADXL345_POWER_CTL_STANDBY	0x00
 
-#define ADXL345_DATA_FORMAT_FULL_RES	BIT(3) /* Up to 13-bits resolution */
+#define ADXL345_DATA_FORMAT_RANGE	GENMASK(1, 0)	/* Set the g range */
+#define ADXL345_DATA_FORMAT_JUSTIFY	BIT(2)	/* Left-justified (MSB) mode */
+#define ADXL345_DATA_FORMAT_FULL_RES	BIT(3)	/* Up to 13-bits resolution */
+#define ADXL345_DATA_FORMAT_SELF_TEST	BIT(7)	/* Enable a self test */
+
 #define ADXL345_DATA_FORMAT_2G		0
 #define ADXL345_DATA_FORMAT_4G		1
 #define ADXL345_DATA_FORMAT_8G		2
@@ -48,7 +52,6 @@
 struct adxl345_data {
 	const struct adxl345_chip_info *info;
 	struct regmap *regmap;
-	u8 data_range;
 };
 
 #define ADXL345_CHANNEL(index, axis) {					\
@@ -202,6 +205,7 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
 	struct adxl345_data *data;
 	struct iio_dev *indio_dev;
 	u32 regval;
+	unsigned int data_format_mask;
 	int ret;
 
 	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
@@ -218,15 +222,23 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
 
 	data = iio_priv(indio_dev);
 	data->regmap = regmap;
-	/* Enable full-resolution mode */
-	data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
 	data->info = device_get_match_data(dev);
 	if (!data->info)
 		return -ENODEV;
 
-	ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
-			   data->data_range);
-	if (ret < 0)
+	/*
+	 * Only allow updates of bus independent bits to the data_format
+	 * register. Keep the bus specific pre-configuration.
+	 */
+	data_format_mask = (ADXL345_DATA_FORMAT_RANGE |
+				  ADXL345_DATA_FORMAT_JUSTIFY |
+				  ADXL345_DATA_FORMAT_FULL_RES |
+				  ADXL345_DATA_FORMAT_SELF_TEST);
+
+	/* 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");
 
 	indio_dev->name = data->info->name;
-- 
2.25.1