157 lines
3.9 KiB
C
Executable file
157 lines
3.9 KiB
C
Executable file
/*
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* IIO driver for the 3-axis accelerometer Domintech DMARD09.
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*
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* Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <asm/unaligned.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#define DMARD09_DRV_NAME "dmard09"
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#define DMARD09_REG_CHIPID 0x18
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#define DMARD09_REG_STAT 0x0A
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#define DMARD09_REG_X 0x0C
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#define DMARD09_REG_Y 0x0E
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#define DMARD09_REG_Z 0x10
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#define DMARD09_CHIPID 0x95
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#define DMARD09_BUF_LEN 8
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#define DMARD09_AXIS_X 0
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#define DMARD09_AXIS_Y 1
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#define DMARD09_AXIS_Z 2
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#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
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#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2)
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#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
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struct dmard09_data {
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struct i2c_client *client;
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};
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#define DMARD09_CHANNEL(_axis, offset) { \
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.type = IIO_ACCEL, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
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.modified = 1, \
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.address = offset, \
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.channel2 = IIO_MOD_##_axis, \
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}
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static const struct iio_chan_spec dmard09_channels[] = {
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DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
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DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
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DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
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};
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static int dmard09_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct dmard09_data *data = iio_priv(indio_dev);
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u8 buf[DMARD09_BUF_LEN];
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int ret;
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s16 accel;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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/*
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* Read from the DMAR09_REG_STAT register, since the chip
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* caches reads from the individual X, Y, Z registers.
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*/
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ret = i2c_smbus_read_i2c_block_data(data->client,
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DMARD09_REG_STAT,
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DMARD09_BUF_LEN, buf);
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if (ret < 0) {
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dev_err(&data->client->dev, "Error reading reg %d\n",
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DMARD09_REG_STAT);
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return ret;
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}
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accel = get_unaligned_le16(&buf[chan->address]);
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/* Remove lower 3 bits and sign extend */
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accel <<= 4;
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accel >>= 7;
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*val = accel;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info dmard09_info = {
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.read_raw = dmard09_read_raw,
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};
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static int dmard09_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int ret;
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struct iio_dev *indio_dev;
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struct dmard09_data *data;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev) {
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dev_err(&client->dev, "iio allocation failed\n");
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return -ENOMEM;
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}
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data = iio_priv(indio_dev);
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data->client = client;
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ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
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if (ret < 0) {
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dev_err(&client->dev, "Error reading chip id %d\n", ret);
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return ret;
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}
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if (ret != DMARD09_CHIPID) {
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dev_err(&client->dev, "Invalid chip id %d\n", ret);
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return -ENODEV;
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}
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i2c_set_clientdata(client, indio_dev);
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indio_dev->dev.parent = &client->dev;
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indio_dev->name = DMARD09_DRV_NAME;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = dmard09_channels;
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indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
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indio_dev->info = &dmard09_info;
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return devm_iio_device_register(&client->dev, indio_dev);
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}
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static const struct i2c_device_id dmard09_id[] = {
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{ "dmard09", 0},
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, dmard09_id);
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static struct i2c_driver dmard09_driver = {
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.driver = {
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.name = DMARD09_DRV_NAME
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},
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.probe = dmard09_probe,
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.id_table = dmard09_id,
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};
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module_i2c_driver(dmard09_driver);
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MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
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MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
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MODULE_LICENSE("GPL");
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