Add basic IIO support for the Analog Devices ADXL345 3-axis accelerometer. The datasheet can be found here: http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf Signed-off-by: Eva Rachel Retuya <eraretuya@xxxxxxxxx> Cc: Michael Hennerich <michael.hennerich@xxxxxxxxxx> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx> Cc: Alison Schofield <amsfield22@xxxxxxxxx> --- v1 Mailing list discussion: https://marc.info/?l=linux-iio&m=148533644407371&w=2 Changes since v1: * Switch tag from RFC to PATCH >From Jonathan's Review * Kconfig: add input driver's (adxl34x) selection state as dependency. >From Peter's Review * Implement full-resolution mode scale. * Add comment stating FULL_RES is up to 13-bits in resolution. * Drop newline and le16_to_cpu usage in read_raw. * Allow the sensor to return to standby mode if iio_device_register fails. drivers/iio/accel/Kconfig | 11 +++ drivers/iio/accel/Makefile | 1 + drivers/iio/accel/adxl345.c | 194 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 206 insertions(+) create mode 100644 drivers/iio/accel/adxl345.c diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig index ef8401a..2308bac 100644 --- a/drivers/iio/accel/Kconfig +++ b/drivers/iio/accel/Kconfig @@ -5,6 +5,17 @@ menu "Accelerometers" +config ADXL345 + tristate "Analog Devices ADXL345 3-Axis Digital Accelerometer Driver" + depends on !(INPUT_ADXL34X=y || INPUT_ADXL34X=m) + depends on 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. + 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 69fe8ed..618488d 100644 --- a/drivers/iio/accel/Makefile +++ b/drivers/iio/accel/Makefile @@ -3,6 +3,7 @@ # # When adding new entries keep the list in alphabetical order +obj-$(CONFIG_ADXL345) += adxl345.o obj-$(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.c b/drivers/iio/accel/adxl345.c new file mode 100644 index 0000000..c34991f --- /dev/null +++ b/drivers/iio/accel/adxl345.c @@ -0,0 +1,194 @@ +/* + * 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. + * + * IIO 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/iio/iio.h> + +#define ADXL345_REG_DEVID 0x00 +#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_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_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. + * + * At +/- 16g with 13-bit resolution, scale is computed as: + * (16 + 16) * 9.81 / (2^13 - 1) = 0.0383 + */ +static const int adxl345_uscale = 38300; + +struct adxl345_data { + struct i2c_client *client; + u8 data_range; +}; + +#define ADXL345_CHANNEL(reg, axis) { \ + .type = IIO_ACCEL, \ + .modified = 1, \ + .channel2 = IIO_MOD_##axis, \ + .address = reg, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +static const struct iio_chan_spec adxl345_channels[] = { + ADXL345_CHANNEL(ADXL345_REG_DATAX0, X), + ADXL345_CHANNEL(ADXL345_REG_DATAY0, Y), + ADXL345_CHANNEL(ADXL345_REG_DATAZ0, Z), +}; + +static int adxl345_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct adxl345_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + /* + * Data is stored in adjacent registers: + * 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); + if (ret < 0) + return ret; + + *val = sign_extend32(ret, 12); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = adxl345_uscale; + + return IIO_VAL_INT_PLUS_MICRO; + } + + return -EINVAL; +} + +static const struct iio_info adxl345_info = { + .driver_module = THIS_MODULE, + .read_raw = adxl345_read_raw, +}; + +static int adxl345_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct adxl345_data *data; + struct iio_dev *indio_dev; + int ret; + + ret = i2c_smbus_read_byte_data(client, ADXL345_REG_DEVID); + if (ret < 0) { + dev_err(&client->dev, "Error reading device ID: %d\n", ret); + return ret; + } + + if (ret != ADXL345_DEVID) { + dev_err(&client->dev, "Invalid device ID: %d\n", ret); + return -ENODEV; + } + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + /* 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); + if (ret < 0) { + dev_err(&client->dev, "Failed to set data range: %d\n", ret); + return ret; + } + + indio_dev->dev.parent = &client->dev; + indio_dev->name = id->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); + if (ret < 0) { + dev_err(&client->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); + } + + return ret; +} + +static int adxl345_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + 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); +} + +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); + +MODULE_AUTHOR("Eva Rachel Retuya <eraretuya@xxxxxxxxx>"); +MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer driver"); +MODULE_LICENSE("GPL v2"); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
