[PATCH v7 0/8] iio: accel: adxl345: Add spi-3wire feature

[PATCH v7 0/8] iio: accel: adxl345: Add spi-3wire feature

[Lothar Rubusch]

Pass a function setup() as pointer from SPI/I2C specific modules to the
core module. Implement setup() to pass the spi-3wire bus option, if
declared in the device-tree.

In the core module then update data_format register configuration bits
instead of overwriting it. The changes allow to remove a data_range field.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
V1 -> V2: Split into spi-3wire and refactoring
V2 -> V3: Split further, focus on needed changesets
V3 -> V4: Drop "Remove single info instances";
          split "Group bus configuration" into separat
          comment patch; reorder patch set
V4 -> V5: Refrase comments; Align comments to 75; rebuild FORMAT_MASK by
          available flags; fix indention
V5 -> V6: Remove FORMAT_MASK by a local variable on call site;
          Refrase comments;
          Remove unneeded include
V6 -> V7: Restructure optional passing the setup() to core's probe()
          Guarantee that initially a regmap_write() was called to init
          all bits to a defined state
          - When a setup() e.g. for 3wire is passed, then call
            regmap_write() inside the setup(). In the following
            core's probe() has to call regmap_update()
          - When NULL is passed, then call regmap_write() in core's
            probe()
          - Refactoring: remove obvious comments and simplify code

Lothar Rubusch (8):
  iio: accel: adxl345: Make data_range obsolete
  iio: accel: adxl345: Group bus configuration
  iio: accel: adxl345: Move defines to header
  dt-bindings: iio: accel: adxl345: Add spi-3wire
  iio: accel: adxl345: Pass function pointer to core
  iio: accel: adxl345: Reorder probe initialization
  iio: accel: adxl345: Add comment to probe
  iio: accel: adxl345: Add spi-3wire option

 .../bindings/iio/accel/adi,adxl345.yaml       |  2 +
 drivers/iio/accel/adxl345.h                   | 36 +++++++-
 drivers/iio/accel/adxl345_core.c              | 92 ++++++++++---------
 drivers/iio/accel/adxl345_i2c.c               |  2 +-
 drivers/iio/accel/adxl345_spi.c               | 10 +-
 5 files changed, 94 insertions(+), 48 deletions(-)

-- 
2.25.1

[PATCH v7 1/8] iio: accel: adxl345: Make data_range obsolete

[Lothar Rubusch]

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 | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 8bd30a23e..ff89215e9 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 +205,10 @@ 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 = (ADXL345_DATA_FORMAT_RANGE |
+					 ADXL345_DATA_FORMAT_JUSTIFY |
+					 ADXL345_DATA_FORMAT_FULL_RES |
+					 ADXL345_DATA_FORMAT_SELF_TEST);
 	int ret;
 
 	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
@@ -218,15 +225,14 @@ 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)
+	/* 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

[PATCH v7 2/8] iio: accel: adxl345: Group bus configuration

[Lothar Rubusch]

Group the indio_dev initialization and bus configuration for improved
readability.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index ff89215e9..e4afc6d2a 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -229,18 +229,18 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap)
 	if (!data->info)
 		return -ENODEV;
 
-	/* 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;
 	indio_dev->info = &adxl345_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	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)
-- 
2.25.1

[PATCH v7 3/8] iio: accel: adxl345: Move defines to header

[Lothar Rubusch]

Move defines from core to the header file. Keep the defines block together
in one location.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345.h      | 32 ++++++++++++++++++++++++++++++++
 drivers/iio/accel/adxl345_core.c | 32 --------------------------------
 2 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
index 284bd387c..732820d34 100644
--- a/drivers/iio/accel/adxl345.h
+++ b/drivers/iio/accel/adxl345.h
@@ -8,6 +8,38 @@
 #ifndef _ADXL345_H_
 #define _ADXL345_H_
 
+#define ADXL345_REG_DEVID		0x00
+#define ADXL345_REG_OFSX		0x1E
+#define ADXL345_REG_OFSY		0x1F
+#define ADXL345_REG_OFSZ		0x20
+#define ADXL345_REG_OFS_AXIS(index)	(ADXL345_REG_OFSX + (index))
+#define ADXL345_REG_BW_RATE		0x2C
+#define ADXL345_REG_POWER_CTL		0x2D
+#define ADXL345_REG_DATA_FORMAT		0x31
+#define ADXL345_REG_DATAX0		0x32
+#define ADXL345_REG_DATAY0		0x34
+#define ADXL345_REG_DATAZ0		0x36
+#define ADXL345_REG_DATA_AXIS(index)	\
+	(ADXL345_REG_DATAX0 + (index) * sizeof(__le16))
+
+#define ADXL345_BW_RATE			GENMASK(3, 0)
+#define ADXL345_BASE_RATE_NANO_HZ	97656250LL
+
+#define ADXL345_POWER_CTL_MEASURE	BIT(3)
+#define ADXL345_POWER_CTL_STANDBY	0x00
+
+#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
+#define ADXL345_DATA_FORMAT_16G		3
+
+#define ADXL345_DEVID			0xE5
+
 /*
  * In full-resolution mode, scale factor is maintained at ~4 mg/LSB
  * in all g ranges.
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index e4afc6d2a..f875a6275 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -17,38 +17,6 @@
 
 #include "adxl345.h"
 
-#define ADXL345_REG_DEVID		0x00
-#define ADXL345_REG_OFSX		0x1e
-#define ADXL345_REG_OFSY		0x1f
-#define ADXL345_REG_OFSZ		0x20
-#define ADXL345_REG_OFS_AXIS(index)	(ADXL345_REG_OFSX + (index))
-#define ADXL345_REG_BW_RATE		0x2C
-#define ADXL345_REG_POWER_CTL		0x2D
-#define ADXL345_REG_DATA_FORMAT		0x31
-#define ADXL345_REG_DATAX0		0x32
-#define ADXL345_REG_DATAY0		0x34
-#define ADXL345_REG_DATAZ0		0x36
-#define ADXL345_REG_DATA_AXIS(index)	\
-	(ADXL345_REG_DATAX0 + (index) * sizeof(__le16))
-
-#define ADXL345_BW_RATE			GENMASK(3, 0)
-#define ADXL345_BASE_RATE_NANO_HZ	97656250LL
-
-#define ADXL345_POWER_CTL_MEASURE	BIT(3)
-#define ADXL345_POWER_CTL_STANDBY	0x00
-
-#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
-#define ADXL345_DATA_FORMAT_16G		3
-
-#define ADXL345_DEVID			0xE5
-
 struct adxl345_data {
 	const struct adxl345_chip_info *info;
 	struct regmap *regmap;
-- 
2.25.1

[PATCH v7 4/8] dt-bindings: iio: accel: adxl345: Add spi-3wire

[Lothar Rubusch]

Add spi-3wire because the device allows to be configured for spi 3-wire
communication.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
index 07cacc3f6..280ed479e 100644
--- a/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
+++ b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
@@ -32,6 +32,8 @@ properties:
 
   spi-cpol: true
 
+  spi-3wire: true
+
   interrupts:
     maxItems: 1
 
-- 
2.25.1

[PATCH v7 5/8] iio: accel: adxl345: Pass function pointer to core

[Lothar Rubusch]

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>
---
 drivers/iio/accel/adxl345.h      |  3 ++-
 drivers/iio/accel/adxl345_core.c | 32 +++++++++++++++++++++++++-------
 drivers/iio/accel/adxl345_i2c.c  |  2 +-
 drivers/iio/accel/adxl345_spi.c  |  2 +-
 4 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
index 732820d34..e859c01d4 100644
--- a/drivers/iio/accel/adxl345.h
+++ b/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_ */
diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index f875a6275..8d4a66d8c 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/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)
diff --git a/drivers/iio/accel/adxl345_i2c.c b/drivers/iio/accel/adxl345_i2c.c
index a3084b0a8..4065b8f7c 100644
--- a/drivers/iio/accel/adxl345_i2c.c
+++ b/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 = {
diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
index 93ca349f1..1c0513bd3 100644
--- a/drivers/iio/accel/adxl345_spi.c
+++ b/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 = {
-- 
2.25.1

[PATCH v7 6/8] iio: accel: adxl345: Reorder probe initialization

[Lothar Rubusch]

Bring indio_dev, setup() and data initialization to begin of the probe()
function to increase readability. Access members through data
pointer to assure implicitely the driver's data instance is correctly
initialized and functional.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 40 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 8d4a66d8c..5d0f3243e 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -180,14 +180,30 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 					 ADXL345_DATA_FORMAT_SELF_TEST);
 	int ret;
 
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->regmap = regmap;
+	data->info = device_get_match_data(dev);
+	if (!data->info)
+		return -ENODEV;
+
+	indio_dev->name = data->info->name;
+	indio_dev->info = &adxl345_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = adxl345_channels;
+	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
+
 	if (setup) {
 		/* Perform optional initial bus specific configuration */
-		ret = setup(dev, regmap);
+		ret = setup(dev, data->regmap);
 		if (ret)
 			return ret;
 
 		/* Enable full-resolution mode */
-		ret = regmap_update_bits(regmap, ADXL345_REG_DATA_FORMAT,
+		ret = regmap_update_bits(data->regmap, ADXL345_REG_DATA_FORMAT,
 					 data_format_mask,
 					 ADXL345_DATA_FORMAT_FULL_RES);
 		if (ret)
@@ -196,14 +212,14 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 
 	} else {
 		/* Enable full-resolution mode (init all data_format bits) */
-		ret = regmap_write(regmap, ADXL345_REG_DATA_FORMAT,
+		ret = regmap_write(data->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);
+	ret = regmap_read(data->regmap, ADXL345_REG_DEVID, &regval);
 	if (ret < 0)
 		return dev_err_probe(dev, ret, "Error reading device ID\n");
 
@@ -211,22 +227,6 @@ int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 		return dev_err_probe(dev, -ENODEV, "Invalid device ID: %x, expected %x\n",
 				     regval, ADXL345_DEVID);
 
-	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
-	if (!indio_dev)
-		return -ENOMEM;
-
-	data = iio_priv(indio_dev);
-	data->regmap = regmap;
-	data->info = device_get_match_data(dev);
-	if (!data->info)
-		return -ENODEV;
-
-	indio_dev->name = data->info->name;
-	indio_dev->info = &adxl345_info;
-	indio_dev->modes = INDIO_DIRECT_MODE;
-	indio_dev->channels = adxl345_channels;
-	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
-
 	/* Enable measurement mode */
 	ret = adxl345_powerup(data->regmap);
 	if (ret < 0)
-- 
2.25.1

[PATCH v7 7/8] iio: accel: adxl345: Add comment to probe

[Lothar Rubusch]

Add a comment to the probe() function to describe the passed function
pointer argument in particular.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345_core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
index 5d0f3243e..006ce66c0 100644
--- a/drivers/iio/accel/adxl345_core.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -168,6 +168,16 @@ static void adxl345_powerdown(void *regmap)
 	regmap_write(regmap, ADXL345_REG_POWER_CTL, ADXL345_POWER_CTL_STANDBY);
 }
 
+/**
+ * adxl345_core_probe() - probe and setup for the adxl345 accelerometer,
+ *                        also covers the adlx375 accelerometer
+ * @dev:	Driver model representation of the device
+ * @regmap:	Regmap instance for the device
+ * @setup:	Setup routine to be executed right before the standard device
+ *		setup
+ *
+ * Return: 0 on success, negative errno on error
+ */
 int adxl345_core_probe(struct device *dev, struct regmap *regmap,
 		       int (*setup)(struct device*, struct regmap*))
 {
-- 
2.25.1

[PATCH v7 8/8] iio: accel: adxl345: Add spi-3wire option

[Lothar Rubusch]

Add a setup function implementation to the spi module to enable spi-3wire
when specified in the device-tree. If spi-3wire is not specified in the
device-tree, NULL is returned as bus pre-initialization. This behavior
is identical to the i2c initialization, hence the default initialization.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
 drivers/iio/accel/adxl345.h     |  1 +
 drivers/iio/accel/adxl345_spi.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
index e859c01d4..3d5c8719d 100644
--- a/drivers/iio/accel/adxl345.h
+++ b/drivers/iio/accel/adxl345.h
@@ -31,6 +31,7 @@
 #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_SPI_3WIRE	BIT(6)	/* 3-wire SPI mode */
 #define ADXL345_DATA_FORMAT_SELF_TEST	BIT(7)	/* Enable a self test */
 
 #define ADXL345_DATA_FORMAT_2G		0
diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
index 1c0513bd3..57e16b441 100644
--- a/drivers/iio/accel/adxl345_spi.c
+++ b/drivers/iio/accel/adxl345_spi.c
@@ -20,6 +20,11 @@ static const struct regmap_config adxl345_spi_regmap_config = {
 	.read_flag_mask = BIT(7) | BIT(6),
 };
 
+static int adxl345_spi_setup(struct device *dev, struct regmap *regmap)
+{
+	return regmap_write(regmap, ADXL345_REG_DATA_FORMAT, ADXL345_DATA_FORMAT_SPI_3WIRE);
+}
+
 static int adxl345_spi_probe(struct spi_device *spi)
 {
 	struct regmap *regmap;
@@ -33,7 +38,10 @@ 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, NULL);
+	if (spi->mode & SPI_3WIRE)
+		return adxl345_core_probe(&spi->dev, regmap, adxl345_spi_setup);
+	else
+		return adxl345_core_probe(&spi->dev, regmap, NULL);
 }
 
 static const struct adxl345_chip_info adxl345_spi_info = {
-- 
2.25.1

Re: [PATCH v7 0/8] iio: accel: adxl345: Add spi-3wire feature

[Jonathan Cameron]

On Mon,  1 Apr 2024 19:48:58 +0000
Lothar Rubusch <l.rubusch@gmail.com> wrote:

> Pass a function setup() as pointer from SPI/I2C specific modules to the
> core module. Implement setup() to pass the spi-3wire bus option, if
> declared in the device-tree.
> 
> In the core module then update data_format register configuration bits
> instead of overwriting it. The changes allow to remove a data_range field.
> 
> Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Series applied to the togreg branch of iio.git and pushed out initially
as testing to let 0-day work it's magic (find build issues for us!)

I'll push it out for linux-next to pick up sometime in next week (ish)

Jonathan

> ---
> V1 -> V2: Split into spi-3wire and refactoring
> V2 -> V3: Split further, focus on needed changesets
> V3 -> V4: Drop "Remove single info instances";
>           split "Group bus configuration" into separat
>           comment patch; reorder patch set
> V4 -> V5: Refrase comments; Align comments to 75; rebuild FORMAT_MASK by
>           available flags; fix indention
> V5 -> V6: Remove FORMAT_MASK by a local variable on call site;
>           Refrase comments;
>           Remove unneeded include
> V6 -> V7: Restructure optional passing the setup() to core's probe()
>           Guarantee that initially a regmap_write() was called to init
>           all bits to a defined state
>           - When a setup() e.g. for 3wire is passed, then call
>             regmap_write() inside the setup(). In the following
>             core's probe() has to call regmap_update()
>           - When NULL is passed, then call regmap_write() in core's
>             probe()
>           - Refactoring: remove obvious comments and simplify code
> 
> Lothar Rubusch (8):
>   iio: accel: adxl345: Make data_range obsolete
>   iio: accel: adxl345: Group bus configuration
>   iio: accel: adxl345: Move defines to header
>   dt-bindings: iio: accel: adxl345: Add spi-3wire
>   iio: accel: adxl345: Pass function pointer to core
>   iio: accel: adxl345: Reorder probe initialization
>   iio: accel: adxl345: Add comment to probe
>   iio: accel: adxl345: Add spi-3wire option
> 
>  .../bindings/iio/accel/adi,adxl345.yaml       |  2 +
>  drivers/iio/accel/adxl345.h                   | 36 +++++++-
>  drivers/iio/accel/adxl345_core.c              | 92 ++++++++++---------
>  drivers/iio/accel/adxl345_i2c.c               |  2 +-
>  drivers/iio/accel/adxl345_spi.c               | 10 +-
>  5 files changed, 94 insertions(+), 48 deletions(-)
>