[PATCH v2 1/4] iio: accel: adxl345: Use I2C regmap instead of direct I2C access

From: Eva Rachel Retuya
Date: Mon Feb 20 2017 - 04:26:29 EST

Convert the driver to use regmap instead of I2C-specific functions.
Also, introduce the header file "adxl345.h" and export the probe and
remove 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@xxxxxxxxx>
---
Changes from v1:
* 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.

drivers/iio/accel/Kconfig | 1 +
drivers/iio/accel/adxl345.c | 88 ++++++++++++++++++++-------------------------
drivers/iio/accel/adxl345.h | 18 ++++++++++
3 files changed, 57 insertions(+), 50 deletions(-)
create mode 100644 drivers/iio/accel/adxl345.h

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..a3bd711 100644
--- a/drivers/iio/accel/adxl345.c
+++ b/drivers/iio/accel/adxl345.c
@@ -7,16 +7,17 @@
* 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
@@ -45,7 +46,7 @@
static const int adxl345_uscale = 38300;

struct adxl345_data {
- struct i2c_client *client;
+ struct regmap *regmap;
u8 data_range;
};

@@ -70,6 +71,7 @@ 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 +80,12 @@ 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;
@@ -99,96 +102,81 @@ 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;
int ret;
+ u32 regval;

- 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->name = id->name;
+ indio_dev->dev.parent = dev;
+ indio_dev->name = 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 = 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;
}
+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);

- 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[] = {
- { "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@xxxxxxxxx>");
-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.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@xxxxxxxxx>
+ *
+ * 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_ */
--
2.7.4