[PATCH v4 0/4] iio: accel: adxl345: Split driver into core and I2C then add SPI support

[PATCH v4 0/4] iio: accel: adxl345: Split driver into core and I2C then add SPI support

[Eva Rachel Retuya]

This patchset modifies the adxl345 to use regmap. In doing so, we can
easily introduce SPI support and let regmap handle the rest.

Recap of basic features: read_raw for x, y and z axes, scale. After
applying this series, driver now supports the SPI protocol and enumeration
of device via device tree.

Changes from v3:
[PATCH 1/4] Documentation: dt-bindings: Document ADXL345 accelerometer binding
* None
[PATCH 2/4] iio: accel: adxl345: Use I2C regmap instead of direct I2C access
* Keep intact I2C client structure which was deleted from v3
* Make use of regmap_get_device to retrieve struct device, use these for
  debugging prints instead of &client->dev.
[PATCH 3/4] iio: accel: adxl345: Split driver into core and I2C
 and
[PATCH 4/4] iio: accel: adxl345: Add SPI support
* Revert to explicit and separate I2C and SPI configuration
* Add OF match table, make it enumerable in ACPI environment (Andy's suggestion)

Changes from v2:
* Drop PATCH 4 iio: accel: adxl345: Add ACPI support
* Add OF match table on both I2C and SPI files and document them

Changes from v1:
[PATCH 1/4]
* Move other deletions from patch 2 in here -- make it clear what got deleted
  and/or modified that is hard to see previously
* Introduce the driver header file "adxl345.h" here instead of doing it in the
  next patch
* Completely omit traces of i2c_client and let this file (adxl345.c) mirror the
  core file on the next patch.
* Improve debugging print about invalid device ID in probe.
[PATCH 2/4]
* Update Kconfig to Jonathan's preferred style
* Improve similarity index from 78% to 100% (rename detection)
[PATCH 4/4]
* Correct acpi_device_id: ADX0345 -> ADS0345

Eva Rachel Retuya (4):
  Documentation: dt-bindings: Document ADXL345 accelerometer binding
  iio: accel: adxl345: Use I2C regmap instead of direct I2C access
  iio: accel: adxl345: Split driver into core and I2C
  iio: accel: adxl345: Add SPI support

 .../devicetree/bindings/iio/accel/adxl345.txt      | 38 +++++++++
 drivers/iio/accel/Kconfig                          | 26 ++++++-
 drivers/iio/accel/Makefile                         |  4 +-
 drivers/iio/accel/adxl345.h                        | 18 +++++
 drivers/iio/accel/{adxl345.c => adxl345_core.c}    | 89 +++++++++-------------
 drivers/iio/accel/adxl345_i2c.c                    | 78 +++++++++++++++++++
 drivers/iio/accel/adxl345_spi.c                    | 83 ++++++++++++++++++++
 7 files changed, 281 insertions(+), 55 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/adxl345.txt
 create mode 100644 drivers/iio/accel/adxl345.h
 rename drivers/iio/accel/{adxl345.c => adxl345_core.c} (62%)
 create mode 100644 drivers/iio/accel/adxl345_i2c.c
 create mode 100644 drivers/iio/accel/adxl345_spi.c

-- 
2.7.4

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[PATCH v4 1/4] Documentation: dt-bindings: Document ADXL345 accelerometer binding

[Eva Rachel Retuya]

Add the device tree binding documentation for the ADXL345 3-axis digital
accelerometer.

Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com>
---
 .../devicetree/bindings/iio/accel/adxl345.txt      | 38 ++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/accel/adxl345.txt

diff --git a/Documentation/devicetree/bindings/iio/accel/adxl345.txt b/Documentation/devicetree/bindings/iio/accel/adxl345.txt
new file mode 100644
index 0000000..e623f4a
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/accel/adxl345.txt
@@ -0,0 +1,38 @@
+Analog Devices ADXL345 3-Axis, +/-(2g/4g/8g/16g) Digital Accelerometer
+
+http://www.analog.com/en/products/mems/accelerometers/adxl345.html
+
+Required properties:
+ - compatible : should be "adi,adxl345"
+ - reg : the I2C address or SPI chip select number of the sensor
+
+Required properties for SPI bus usage:
+ - spi-max-frequency : set maximum clock frequency, must be 5000000
+ - spi-cpol and spi-cpha : must be defined for adxl345 to enable SPI mode 3
+
+Optional properties:
+ - interrupt-parent : phandle to the parent interrupt controller as documented
+   in Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+ - interrupts: interrupt mapping for IRQ as documented in
+   Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
+
+Example for a I2C device node:
+
+	adxl345@2a {
+		compatible = "adi,adxl345";
+		reg = <0x53>;
+		interrupt-parent = <&gpio1>;
+		interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
+	};
+
+Example for a SPI device node:
+
+	adxl345@0 {
+		compatible = "adi,adxl345";
+		reg = <0>;
+		spi-max-frequency = <5000000>;
+		spi-cpol;
+		spi-cpha;
+		interrupt-parent = <&gpio1>;
+		interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
+	};
-- 
2.7.4

Re: [PATCH v4 1/4] Documentation: dt-bindings: Document ADXL345 accelerometer binding

[Rob Herring]

On Sun, Feb 26, 2017 at 09:45:04PM +0800, Eva Rachel Retuya wrote:
> Add the device tree binding documentation for the ADXL345 3-axis digital
> accelerometer.

Use "dt-bindings: iio: accel: ..." for the subject prefix.

> 
> Signed-off-by: Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  .../devicetree/bindings/iio/accel/adxl345.txt      | 38 ++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/accel/adxl345.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/accel/adxl345.txt b/Documentation/devicetree/bindings/iio/accel/adxl345.txt
> new file mode 100644
> index 0000000..e623f4a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/accel/adxl345.txt
> @@ -0,0 +1,38 @@
> +Analog Devices ADXL345 3-Axis, +/-(2g/4g/8g/16g) Digital Accelerometer
> +
> +http://www.analog.com/en/products/mems/accelerometers/adxl345.html
> +
> +Required properties:
> + - compatible : should be "adi,adxl345"
> + - reg : the I2C address or SPI chip select number of the sensor
> +
> +Required properties for SPI bus usage:
> + - spi-max-frequency : set maximum clock frequency, must be 5000000
> + - spi-cpol and spi-cpha : must be defined for adxl345 to enable SPI mode 3
> +
> +Optional properties:
> + - interrupt-parent : phandle to the parent interrupt controller as documented
> +   in Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
> + - interrupts: interrupt mapping for IRQ as documented in
> +   Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
> +
> +Example for a I2C device node:
> +
> +	adxl345@2a {

accelerometer@2a

> +		compatible = "adi,adxl345";
> +		reg = <0x53>;
> +		interrupt-parent = <&gpio1>;
> +		interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
> +	};
> +
> +Example for a SPI device node:
> +
> +	adxl345@0 {

Same here.

> +		compatible = "adi,adxl345";
> +		reg = <0>;
> +		spi-max-frequency = <5000000>;
> +		spi-cpol;
> +		spi-cpha;
> +		interrupt-parent = <&gpio1>;
> +		interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
> +	};
> -- 
> 2.7.4
> 

[PATCH v4 2/4] iio: accel: adxl345: Use I2C regmap instead of direct I2C access

[Eva Rachel Retuya]

Convert the driver to use regmap instead of I2C-specific functions. This
is done in preparation for splitting this driver into core and
I2C-specific code as well as introduction of SPI driver.

Signed-off-by: Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Changes from v3:
* Keep intact I2C client structure which was deleted from v3
* Make use of regmap_get_device to retrieve struct device, use these for
  debugging prints instead of &client->dev.

 drivers/iio/accel/Kconfig   |  1 +
 drivers/iio/accel/adxl345.c | 66 +++++++++++++++++++++++++++++----------------
 2 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 2308bac..26b8614 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -9,6 +9,7 @@ config ADXL345
 	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer Driver"
 	depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m)
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  Say Y here if you want to build support for the Analog Devices
 	  ADXL345 3-axis digital accelerometer.
diff --git a/drivers/iio/accel/adxl345.c b/drivers/iio/accel/adxl345.c
index c34991f..bec8bec 100644
--- a/drivers/iio/accel/adxl345.c
+++ b/drivers/iio/accel/adxl345.c
@@ -14,6 +14,7 @@
 
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/regmap.h>
 
 #include <linux/iio/iio.h>
 
@@ -45,10 +46,15 @@
 static const int adxl345_uscale = 38300;
 
 struct adxl345_data {
-	struct i2c_client *client;
+	struct regmap *regmap;
 	u8 data_range;
 };
 
+static const struct regmap_config adxl345_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
 #define ADXL345_CHANNEL(reg, axis) {					\
 	.type = IIO_ACCEL,						\
 	.modified = 1,							\
@@ -70,6 +76,7 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 {
 	struct adxl345_data *data = iio_priv(indio_dev);
 	int ret;
+	__le16 regval;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
@@ -78,11 +85,12 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
 		 * ADXL345_REG_DATA(X0/Y0/Z0) contain the least significant byte
 		 * and ADXL345_REG_DATA(X0/Y0/Z0) + 1 the most significant byte
 		 */
-		ret = i2c_smbus_read_word_data(data->client, chan->address);
+		ret = regmap_bulk_read(data->regmap, chan->address, &regval,
+				       sizeof(regval));
 		if (ret < 0)
 			return ret;
 
-		*val = sign_extend32(ret, 12);
+		*val = sign_extend32(le16_to_cpu(regval), 12);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*val = 0;
@@ -104,37 +112,50 @@ static int adxl345_probe(struct i2c_client *client,
 {
 	struct adxl345_data *data;
 	struct iio_dev *indio_dev;
+	struct device *dev;
+	struct regmap *regmap;
 	int ret;
+	u32 regval;
+
+	regmap = devm_regmap_init_i2c(client, &adxl345_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Error initializing regmap: %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	dev = regmap_get_device(regmap);
 
-	ret = i2c_smbus_read_byte_data(client, ADXL345_REG_DEVID);
+	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
 	if (ret < 0) {
-		dev_err(&client->dev, "Error reading device ID: %d\n", ret);
+		dev_err(dev, "Error reading device ID: %d\n", ret);
 		return ret;
 	}
 
-	if (ret != ADXL345_DEVID) {
-		dev_err(&client->dev, "Invalid device ID: %d\n", ret);
+	if (regval != ADXL345_DEVID) {
+		dev_err(dev, "Invalid device ID: %x, expected %x\n",
+			regval, ADXL345_DEVID);
 		return -ENODEV;
 	}
 
-	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
 
 	data = iio_priv(indio_dev);
-	i2c_set_clientdata(client, indio_dev);
-	data->client = client;
+	dev_set_drvdata(dev, indio_dev);
+	data->regmap = regmap;
 	/* Enable full-resolution mode */
 	data->data_range = ADXL345_DATA_FORMAT_FULL_RES;
 
-	ret = i2c_smbus_write_byte_data(data->client, ADXL345_REG_DATA_FORMAT,
-					data->data_range);
+	ret = regmap_write(data->regmap, ADXL345_REG_DATA_FORMAT,
+			   data->data_range);
 	if (ret < 0) {
-		dev_err(&client->dev, "Failed to set data range: %d\n", ret);
+		dev_err(dev, "Failed to set data range: %d\n", ret);
 		return ret;
 	}
 
-	indio_dev->dev.parent = &client->dev;
+	indio_dev->dev.parent = dev;
 	indio_dev->name = id->name;
 	indio_dev->info = &adxl345_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -142,19 +163,18 @@ static int adxl345_probe(struct i2c_client *client,
 	indio_dev->num_channels = ARRAY_SIZE(adxl345_channels);
 
 	/* Enable measurement mode */
-	ret = i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,
-					ADXL345_POWER_CTL_MEASURE);
+	ret = regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
+			   ADXL345_POWER_CTL_MEASURE);
 	if (ret < 0) {
-		dev_err(&client->dev, "Failed to enable measurement mode: %d\n",
-			ret);
+		dev_err(dev, "Failed to enable measurement mode: %d\n", ret);
 		return ret;
 	}
 
 	ret = iio_device_register(indio_dev);
 	if (ret < 0) {
-		dev_err(&client->dev, "iio_device_register failed: %d\n", ret);
-		i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,
-					  ADXL345_POWER_CTL_STANDBY);
+		dev_err(dev, "iio_device_register failed: %d\n", ret);
+		regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
+			     ADXL345_POWER_CTL_STANDBY);
 	}
 
 	return ret;
@@ -167,8 +187,8 @@ static int adxl345_remove(struct i2c_client *client)
 
 	iio_device_unregister(indio_dev);
 
-	return i2c_smbus_write_byte_data(data->client, ADXL345_REG_POWER_CTL,
-					 ADXL345_POWER_CTL_STANDBY);
+	return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
+			    ADXL345_POWER_CTL_STANDBY);
 }
 
 static const struct i2c_device_id adxl345_i2c_id[] = {
-- 
2.7.4

[PATCH v4 3/4] iio: accel: adxl345: Split driver into core and I2C

[Eva Rachel Retuya]

Move I2C-specific code into its own file and rely on regmap to access
registers. The core code provides access to x, y, z and scale readings.

Signed-off-by: Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Changes from v3:
* Revert to explicit and separate I2C and SPI configuration
* Add OF match table, make it enumerable in ACPI environment (Andy's suggestion)

 drivers/iio/accel/Kconfig                       | 11 +++-
 drivers/iio/accel/Makefile                      |  3 +-
 drivers/iio/accel/adxl345.h                     | 18 ++++++
 drivers/iio/accel/{adxl345.c => adxl345_core.c} | 55 ++++-------------
 drivers/iio/accel/adxl345_i2c.c                 | 78 +++++++++++++++++++++++++
 5 files changed, 117 insertions(+), 48 deletions(-)
 create mode 100644 drivers/iio/accel/adxl345.h
 rename drivers/iio/accel/{adxl345.c => adxl345_core.c} (78%)
 create mode 100644 drivers/iio/accel/adxl345_i2c.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 26b8614..9f5a889 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -6,16 +6,21 @@
 menu "Accelerometers"
 
 config ADXL345
-	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer Driver"
+	tristate
+
+config ADXL345_I2C
+	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer I2C Driver"
 	depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m)
 	depends on I2C
+	select ADXL345
 	select REGMAP_I2C
 	help
 	  Say Y here if you want to build support for the Analog Devices
 	  ADXL345 3-axis digital accelerometer.
 
-	  To compile this driver as a module, choose M here: the
-	  module will be called adxl345.
+	  To compile this driver as a module, choose M here: the module
+	  will be called adxl345_i2c and you will also get adxl345_core
+	  for the core module.
 
 config BMA180
 	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 618488d..3f4a6d6 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -3,7 +3,8 @@
 #
 
 # When adding new entries keep the list in alphabetical order
-obj-$(CONFIG_ADXL345) += adxl345.o
+obj-$(CONFIG_ADXL345) += adxl345_core.o
+obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMA220) += bma220_spi.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
diff --git a/drivers/iio/accel/adxl345.h b/drivers/iio/accel/adxl345.h
new file mode 100644
index 0000000..fca3e25
--- /dev/null
+++ b/drivers/iio/accel/adxl345.h
@@ -0,0 +1,18 @@
+/*
+ * ADXL345 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2017 Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ */
+
+#ifndef _ADXL345_H_
+#define _ADXL345_H_
+
+int adxl345_common_probe(struct device *dev, struct regmap *regmap,
+			 const char *name);
+int adxl345_common_remove(struct device *dev);
+
+#endif /* _ADXL345_H_ */
diff --git a/drivers/iio/accel/adxl345.c b/drivers/iio/accel/adxl345_core.c
similarity index 78%
rename from drivers/iio/accel/adxl345.c
rename to drivers/iio/accel/adxl345_core.c
index bec8bec..9dea6a5 100644
--- a/drivers/iio/accel/adxl345.c
+++ b/drivers/iio/accel/adxl345_core.c
@@ -7,17 +7,16 @@
  * the GNU General Public License. See the file COPYING in the main
  * directory of this archive for more details.
  *
- * IIO driver for ADXL345
- * 7-bit I2C slave address: 0x1D (ALT ADDRESS pin tied to VDDIO) or
- * 0x53 (ALT ADDRESS pin grounded)
+ * IIO core driver for ADXL345
  */
 
-#include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
 
 #include <linux/iio/iio.h>
 
+#include "adxl345.h"
+
 #define ADXL345_REG_DEVID		0x00
 #define ADXL345_REG_POWER_CTL		0x2D
 #define ADXL345_REG_DATA_FORMAT		0x31
@@ -50,11 +49,6 @@ struct adxl345_data {
 	u8 data_range;
 };
 
-static const struct regmap_config adxl345_regmap_config = {
-	.reg_bits = 8,
-	.val_bits = 8,
-};
-
 #define ADXL345_CHANNEL(reg, axis) {					\
 	.type = IIO_ACCEL,						\
 	.modified = 1,							\
@@ -107,25 +101,14 @@ static const struct iio_info adxl345_info = {
 	.read_raw	= adxl345_read_raw,
 };
 
-static int adxl345_probe(struct i2c_client *client,
-			 const struct i2c_device_id *id)
+int adxl345_common_probe(struct device *dev, struct regmap *regmap,
+			 const char *name)
 {
 	struct adxl345_data *data;
 	struct iio_dev *indio_dev;
-	struct device *dev;
-	struct regmap *regmap;
 	int ret;
 	u32 regval;
 
-	regmap = devm_regmap_init_i2c(client, &adxl345_regmap_config);
-	if (IS_ERR(regmap)) {
-		dev_err(&client->dev, "Error initializing regmap: %d\n",
-			(int)PTR_ERR(regmap));
-		return PTR_ERR(regmap);
-	}
-
-	dev = regmap_get_device(regmap);
-
 	ret = regmap_read(regmap, ADXL345_REG_DEVID, &regval);
 	if (ret < 0) {
 		dev_err(dev, "Error reading device ID: %d\n", ret);
@@ -156,7 +139,7 @@ static int adxl345_probe(struct i2c_client *client,
 	}
 
 	indio_dev->dev.parent = dev;
-	indio_dev->name = id->name;
+	indio_dev->name = name;
 	indio_dev->info = &adxl345_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = adxl345_channels;
@@ -179,10 +162,11 @@ static int adxl345_probe(struct i2c_client *client,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(adxl345_common_probe);
 
-static int adxl345_remove(struct i2c_client *client)
+int adxl345_common_remove(struct device *dev)
 {
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct adxl345_data *data = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
@@ -190,25 +174,8 @@ static int adxl345_remove(struct i2c_client *client)
 	return regmap_write(data->regmap, ADXL345_REG_POWER_CTL,
 			    ADXL345_POWER_CTL_STANDBY);
 }
-
-static const struct i2c_device_id adxl345_i2c_id[] = {
-	{ "adxl345", 0 },
-	{ }
-};
-
-MODULE_DEVICE_TABLE(i2c, adxl345_i2c_id);
-
-static struct i2c_driver adxl345_driver = {
-	.driver = {
-		.name	= "adxl345",
-	},
-	.probe		= adxl345_probe,
-	.remove		= adxl345_remove,
-	.id_table	= adxl345_i2c_id,
-};
-
-module_i2c_driver(adxl345_driver);
+EXPORT_SYMBOL_GPL(adxl345_common_remove);
 
 MODULE_AUTHOR("Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
-MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer driver");
+MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer core driver");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/accel/adxl345_i2c.c b/drivers/iio/accel/adxl345_i2c.c
new file mode 100644
index 0000000..19053be
--- /dev/null
+++ b/drivers/iio/accel/adxl345_i2c.c
@@ -0,0 +1,78 @@
+/*
+ * ADXL345 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2017 Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * I2C driver for ADXL345
+ * 7-bit I2C slave address: 0x1D (ALT ADDRESS pin tied to VDDIO) or
+ * 0x53 (ALT ADDRESS pin grounded)
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "adxl345.h"
+
+static const struct regmap_config adxl345_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int adxl345_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct regmap *regmap;
+	const char *name = NULL;
+
+	regmap = devm_regmap_init_i2c(client, &adxl345_i2c_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Error initializing i2c regmap: %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	if (id)
+		name = id->name;
+
+	return adxl345_common_probe(&client->dev, regmap, name);
+}
+
+static int adxl345_i2c_remove(struct i2c_client *client)
+{
+	return adxl345_common_remove(&client->dev);
+}
+
+static const struct i2c_device_id adxl345_i2c_id[] = {
+	{ "adxl345", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, adxl345_i2c_id);
+
+static const struct of_device_id adxl345_of_match[] = {
+	{ .compatible = "adi,adxl345" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, adxl345_of_match);
+
+static struct i2c_driver adxl345_i2c_driver = {
+	.driver = {
+		.name	= "adxl345_i2c",
+		.of_match_table = adxl345_of_match,
+	},
+	.probe		= adxl345_i2c_probe,
+	.remove		= adxl345_i2c_remove,
+	.id_table	= adxl345_i2c_id,
+};
+
+module_i2c_driver(adxl345_i2c_driver);
+
+MODULE_AUTHOR("Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
+MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer I2C driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH v4 4/4] iio: accel: adxl345: Add SPI support

[Eva Rachel Retuya]

Add SPI driver that initializes SPI regmap for the adxl345 core driver.
The driver supports the same functionality as I2C namely the x, y, z and
scale readings.

Signed-off-by: Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Changes from v3:
* Revert to explicit and separate I2C and SPI configuration
* Add OF match table, make it enumerable in ACPI environment (Andy's suggestion)

 drivers/iio/accel/Kconfig       | 14 +++++++
 drivers/iio/accel/Makefile      |  1 +
 drivers/iio/accel/adxl345_spi.c | 83 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 drivers/iio/accel/adxl345_spi.c

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 9f5a889..8994175 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -22,6 +22,20 @@ config ADXL345_I2C
 	  will be called adxl345_i2c and you will also get adxl345_core
 	  for the core module.
 
+config ADXL345_SPI
+	tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer SPI Driver"
+	depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m)
+	depends on SPI
+	select ADXL345
+	select REGMAP_SPI
+	help
+	  Say Y here if you want to build support for the Analog Devices
+	  ADXL345 3-axis digital accelerometer.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called adxl345_spi and you will also get adxl345_core
+	  for the core module.
+
 config BMA180
 	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"
 	depends on I2C
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index 3f4a6d6..31fba19 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -5,6 +5,7 @@
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_ADXL345) += adxl345_core.o
 obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
+obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMA220) += bma220_spi.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
diff --git a/drivers/iio/accel/adxl345_spi.c b/drivers/iio/accel/adxl345_spi.c
new file mode 100644
index 0000000..b7c2e7f
--- /dev/null
+++ b/drivers/iio/accel/adxl345_spi.c
@@ -0,0 +1,83 @@
+/*
+ * ADXL345 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2017 Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * SPI driver for ADXL345
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "adxl345.h"
+
+#define ADXL345_MAX_SPI_FREQ_HZ		5000000
+
+static const struct regmap_config adxl345_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	 /* Setting bits 7 and 6 enables multiple-byte read */
+	.read_flag_mask = BIT(7) | BIT(6),
+};
+
+static int adxl345_spi_probe(struct spi_device *spi)
+{
+	struct regmap *regmap;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+
+	/* Bail out if max_speed_hz exceeds 5 MHz */
+	if (spi->max_speed_hz > ADXL345_MAX_SPI_FREQ_HZ) {
+		dev_err(&spi->dev, "SPI CLK, %d Hz exceeds 5 MHz\n",
+			spi->max_speed_hz);
+		return -EINVAL;
+	}
+
+	regmap = devm_regmap_init_spi(spi, &adxl345_spi_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&spi->dev, "Error initializing spi regmap: %d\n",
+			(int)PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+
+	return adxl345_common_probe(&spi->dev, regmap, id->name);
+}
+
+static int adxl345_spi_remove(struct spi_device *spi)
+{
+	return adxl345_common_remove(&spi->dev);
+}
+
+static const struct spi_device_id adxl345_spi_id[] = {
+	{ "adxl345", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(spi, adxl345_spi_id);
+
+static const struct of_device_id adxl345_of_match[] = {
+	{ .compatible = "adi,adxl345" },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, adxl345_of_match);
+
+static struct spi_driver adxl345_spi_driver = {
+	.driver = {
+		.name	= "adxl345_spi",
+		.of_match_table = adxl345_of_match,
+	},
+	.probe		= adxl345_spi_probe,
+	.remove		= adxl345_spi_remove,
+	.id_table	= adxl345_spi_id,
+};
+
+module_spi_driver(adxl345_spi_driver);
+
+MODULE_AUTHOR("Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
+MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer SPI driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: [PATCH v4 0/4] iio: accel: adxl345: Split driver into core and I2C then add SPI support

[Andy Shevchenko]

On Sun, Feb 26, 2017 at 3:45 PM, Eva Rachel Retuya <eraretuya-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> This patchset modifies the adxl345 to use regmap. In doing so, we can
> easily introduce SPI support and let regmap handle the rest.
>
> Recap of basic features: read_raw for x, y and z axes, scale. After
> applying this series, driver now supports the SPI protocol and enumeration
> of device via device tree.

I did couple of rounds of review and found no major issues with the
series (though, I would amend some style there and minor things). So,
for moving forward FWIW:

Reviewed-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

>
> Changes from v3:
> [PATCH 1/4] Documentation: dt-bindings: Document ADXL345 accelerometer binding
> * None
> [PATCH 2/4] iio: accel: adxl345: Use I2C regmap instead of direct I2C access
> * Keep intact I2C client structure which was deleted from v3
> * Make use of regmap_get_device to retrieve struct device, use these for
>   debugging prints instead of &client->dev.
> [PATCH 3/4] iio: accel: adxl345: Split driver into core and I2C
>  and
> [PATCH 4/4] iio: accel: adxl345: Add SPI support
> * Revert to explicit and separate I2C and SPI configuration
> * Add OF match table, make it enumerable in ACPI environment (Andy's suggestion)
>
> Changes from v2:
> * Drop PATCH 4 iio: accel: adxl345: Add ACPI support
> * Add OF match table on both I2C and SPI files and document them
>
> Changes from v1:
> [PATCH 1/4]
> * Move other deletions from patch 2 in here -- make it clear what got deleted
>   and/or modified that is hard to see previously
> * Introduce the driver header file "adxl345.h" here instead of doing it in the
>   next patch
> * Completely omit traces of i2c_client and let this file (adxl345.c) mirror the
>   core file on the next patch.
> * Improve debugging print about invalid device ID in probe.
> [PATCH 2/4]
> * Update Kconfig to Jonathan's preferred style
> * Improve similarity index from 78% to 100% (rename detection)
> [PATCH 4/4]
> * Correct acpi_device_id: ADX0345 -> ADS0345
>
> Eva Rachel Retuya (4):
>   Documentation: dt-bindings: Document ADXL345 accelerometer binding
>   iio: accel: adxl345: Use I2C regmap instead of direct I2C access
>   iio: accel: adxl345: Split driver into core and I2C
>   iio: accel: adxl345: Add SPI support
>
>  .../devicetree/bindings/iio/accel/adxl345.txt      | 38 +++++++++
>  drivers/iio/accel/Kconfig                          | 26 ++++++-
>  drivers/iio/accel/Makefile                         |  4 +-
>  drivers/iio/accel/adxl345.h                        | 18 +++++
>  drivers/iio/accel/{adxl345.c => adxl345_core.c}    | 89 +++++++++-------------
>  drivers/iio/accel/adxl345_i2c.c                    | 78 +++++++++++++++++++
>  drivers/iio/accel/adxl345_spi.c                    | 83 ++++++++++++++++++++
>  7 files changed, 281 insertions(+), 55 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/iio/accel/adxl345.txt
>  create mode 100644 drivers/iio/accel/adxl345.h
>  rename drivers/iio/accel/{adxl345.c => adxl345_core.c} (62%)
>  create mode 100644 drivers/iio/accel/adxl345_i2c.c
>  create mode 100644 drivers/iio/accel/adxl345_spi.c
>
> --
> 2.7.4
>



-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 0/4] iio: accel: adxl345: Split driver into core and I2C then add SPI support

[Eva Rachel Retuya]

On Tue, Feb 28, 2017 at 12:41:50AM +0200, Andy Shevchenko wrote:
[...]
> I did couple of rounds of review and found no major issues with the
> series (though, I would amend some style there and minor things). So,
> for moving forward FWIW:
> 
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Hello Andy, thank you for the previous feedback and for reviewing this series.

Eva

[...]