LXR linux/drivers/iio/accel/dmard09.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * IIO driver for the 3-axis accelerometer Domintech DMARD09.
   4 *
   5 * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
   6 */
   7
   8#include <asm/unaligned.h>
   9#include <linux/module.h>
  10#include <linux/i2c.h>
  11#include <linux/iio/iio.h>
  12
  13#define DMARD09_DRV_NAME        "dmard09"
  14
  15#define DMARD09_REG_CHIPID      0x18
  16#define DMARD09_REG_STAT        0x0A
  17#define DMARD09_REG_X           0x0C
  18#define DMARD09_REG_Y           0x0E
  19#define DMARD09_REG_Z           0x10
  20#define DMARD09_CHIPID          0x95
  21
  22#define DMARD09_BUF_LEN 8
  23#define DMARD09_AXIS_X 0
  24#define DMARD09_AXIS_Y 1
  25#define DMARD09_AXIS_Z 2
  26#define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
  27#define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1 )* 2)
  28#define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
  29
  30struct dmard09_data {
  31        struct i2c_client *client;
  32};
  33
  34#define DMARD09_CHANNEL(_axis, offset) {                        \
  35        .type = IIO_ACCEL,                                      \
  36        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  37        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  38        .modified = 1,                                          \
  39        .address = offset,                                      \
  40        .channel2 = IIO_MOD_##_axis,                            \
  41}
  42
  43static const struct iio_chan_spec dmard09_channels[] = {
  44        DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
  45        DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
  46        DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
  47};
  48
  49static int dmard09_read_raw(struct iio_dev *indio_dev,
  50                            struct iio_chan_spec const *chan,
  51                            int *val, int *val2, long mask)
  52{
  53        struct dmard09_data *data = iio_priv(indio_dev);
  54        u8 buf[DMARD09_BUF_LEN];
  55        int ret;
  56        s16 accel;
  57
  58        switch (mask) {
  59        case IIO_CHAN_INFO_RAW:
  60                /*
  61                 * Read from the DMAR09_REG_STAT register, since the chip
  62                 * caches reads from the individual X, Y, Z registers.
  63                 */
  64                ret = i2c_smbus_read_i2c_block_data(data->client,
  65                                                    DMARD09_REG_STAT,
  66                                                    DMARD09_BUF_LEN, buf);
  67                if (ret < 0) {
  68                        dev_err(&data->client->dev, "Error reading reg %d\n",
  69                                DMARD09_REG_STAT);
  70                        return ret;
  71                }
  72
  73                accel = get_unaligned_le16(&buf[chan->address]);
  74
  75                /* Remove lower 3 bits and sign extend */
  76                accel <<= 4;
  77                accel >>= 7;
  78
  79                *val = accel;
  80
  81                return IIO_VAL_INT;
  82        default:
  83                return -EINVAL;
  84        }
  85}
  86
  87static const struct iio_info dmard09_info = {
  88        .read_raw       = dmard09_read_raw,
  89};
  90
  91static int dmard09_probe(struct i2c_client *client,
  92                        const struct i2c_device_id *id)
  93{
  94        int ret;
  95        struct iio_dev *indio_dev;
  96        struct dmard09_data *data;
  97
  98        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
  99        if (!indio_dev) {
 100                dev_err(&client->dev, "iio allocation failed\n");
 101                return -ENOMEM;
 102        }
 103
 104        data = iio_priv(indio_dev);
 105        data->client = client;
 106
 107        ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
 108        if (ret < 0) {
 109                dev_err(&client->dev, "Error reading chip id %d\n", ret);
 110                return ret;
 111        }
 112
 113        if (ret != DMARD09_CHIPID) {
 114                dev_err(&client->dev, "Invalid chip id %d\n", ret);
 115                return -ENODEV;
 116        }
 117
 118        i2c_set_clientdata(client, indio_dev);
 119        indio_dev->name = DMARD09_DRV_NAME;
 120        indio_dev->modes = INDIO_DIRECT_MODE;
 121        indio_dev->channels = dmard09_channels;
 122        indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
 123        indio_dev->info = &dmard09_info;
 124
 125        return devm_iio_device_register(&client->dev, indio_dev);
 126}
 127
 128static const struct i2c_device_id dmard09_id[] = {
 129        { "dmard09", 0 },
 130        { },
 131};
 132
 133MODULE_DEVICE_TABLE(i2c, dmard09_id);
 134
 135static struct i2c_driver dmard09_driver = {
 136        .driver = {
 137                .name = DMARD09_DRV_NAME
 138        },
 139        .probe = dmard09_probe,
 140        .id_table = dmard09_id,
 141};
 142
 143module_i2c_driver(dmard09_driver);
 144
 145MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
 146MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
 147MODULE_LICENSE("GPL");
 148