--- /dev/null
+/*
+ * ADXL345 3-Axis Digital Accelerometer
+ *
+ * Copyright (c) 2017 Eva Rachel Retuya <eraretuya@gmail.com>
+ *
+ * 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@gmail.com>");
+MODULE_DESCRIPTION("ADXL345 3-Axis Digital Accelerometer driver");
+MODULE_LICENSE("GPL v2");
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff