iio/accel/dmard09.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * IIO driver for the 3-axis accelerometer Domintech DMARD09.
0004  *
0005  * Copyright (c) 2016, Jelle van der Waa <jelle@vdwaa.nl>
0006  */
0007
0008 #include <asm/unaligned.h>
0009 #include <linux/module.h>
0010 #include <linux/i2c.h>
0011 #include <linux/iio/iio.h>
0012
0013 #define DMARD09_DRV_NAME    "dmard09"
0014
0015 #define DMARD09_REG_CHIPID      0x18
0016 #define DMARD09_REG_STAT    0x0A
0017 #define DMARD09_REG_X       0x0C
0018 #define DMARD09_REG_Y       0x0E
0019 #define DMARD09_REG_Z       0x10
0020 #define DMARD09_CHIPID      0x95
0021
0022 #define DMARD09_BUF_LEN 8
0023 #define DMARD09_AXIS_X 0
0024 #define DMARD09_AXIS_Y 1
0025 #define DMARD09_AXIS_Z 2
0026 #define DMARD09_AXIS_X_OFFSET ((DMARD09_AXIS_X + 1) * 2)
0027 #define DMARD09_AXIS_Y_OFFSET ((DMARD09_AXIS_Y + 1) * 2)
0028 #define DMARD09_AXIS_Z_OFFSET ((DMARD09_AXIS_Z + 1) * 2)
0029
0030 struct dmard09_data {
0031     struct i2c_client *client;
0032 };
0033
0034 #define DMARD09_CHANNEL(_axis, offset) {            \
0035     .type = IIO_ACCEL,                  \
0036     .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),       \
0037     .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
0038     .modified = 1,                      \
0039     .address = offset,                  \
0040     .channel2 = IIO_MOD_##_axis,                \
0041 }
0042
0043 static const struct iio_chan_spec dmard09_channels[] = {
0044     DMARD09_CHANNEL(X, DMARD09_AXIS_X_OFFSET),
0045     DMARD09_CHANNEL(Y, DMARD09_AXIS_Y_OFFSET),
0046     DMARD09_CHANNEL(Z, DMARD09_AXIS_Z_OFFSET),
0047 };
0048
0049 static int dmard09_read_raw(struct iio_dev *indio_dev,
0050                 struct iio_chan_spec const *chan,
0051                 int *val, int *val2, long mask)
0052 {
0053     struct dmard09_data *data = iio_priv(indio_dev);
0054     u8 buf[DMARD09_BUF_LEN];
0055     int ret;
0056     s16 accel;
0057
0058     switch (mask) {
0059     case IIO_CHAN_INFO_RAW:
0060         /*
0061          * Read from the DMAR09_REG_STAT register, since the chip
0062          * caches reads from the individual X, Y, Z registers.
0063          */
0064         ret = i2c_smbus_read_i2c_block_data(data->client,
0065                             DMARD09_REG_STAT,
0066                             DMARD09_BUF_LEN, buf);
0067         if (ret < 0) {
0068             dev_err(&data->client->dev, "Error reading reg %d\n",
0069                 DMARD09_REG_STAT);
0070             return ret;
0071         }
0072
0073         accel = get_unaligned_le16(&buf[chan->address]);
0074
0075         /* Remove lower 3 bits and sign extend */
0076         accel <<= 4;
0077         accel >>= 7;
0078
0079         *val = accel;
0080
0081         return IIO_VAL_INT;
0082     default:
0083         return -EINVAL;
0084     }
0085 }
0086
0087 static const struct iio_info dmard09_info = {
0088     .read_raw   = dmard09_read_raw,
0089 };
0090
0091 static int dmard09_probe(struct i2c_client *client,
0092             const struct i2c_device_id *id)
0093 {
0094     int ret;
0095     struct iio_dev *indio_dev;
0096     struct dmard09_data *data;
0097
0098     indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
0099     if (!indio_dev) {
0100         dev_err(&client->dev, "iio allocation failed\n");
0101         return -ENOMEM;
0102     }
0103
0104     data = iio_priv(indio_dev);
0105     data->client = client;
0106
0107     ret = i2c_smbus_read_byte_data(data->client, DMARD09_REG_CHIPID);
0108     if (ret < 0) {
0109         dev_err(&client->dev, "Error reading chip id %d\n", ret);
0110         return ret;
0111     }
0112
0113     if (ret != DMARD09_CHIPID) {
0114         dev_err(&client->dev, "Invalid chip id %d\n", ret);
0115         return -ENODEV;
0116     }
0117
0118     i2c_set_clientdata(client, indio_dev);
0119     indio_dev->name = DMARD09_DRV_NAME;
0120     indio_dev->modes = INDIO_DIRECT_MODE;
0121     indio_dev->channels = dmard09_channels;
0122     indio_dev->num_channels = ARRAY_SIZE(dmard09_channels);
0123     indio_dev->info = &dmard09_info;
0124
0125     return devm_iio_device_register(&client->dev, indio_dev);
0126 }
0127
0128 static const struct i2c_device_id dmard09_id[] = {
0129     { "dmard09", 0 },
0130     { },
0131 };
0132
0133 MODULE_DEVICE_TABLE(i2c, dmard09_id);
0134
0135 static struct i2c_driver dmard09_driver = {
0136     .driver = {
0137         .name = DMARD09_DRV_NAME
0138     },
0139     .probe = dmard09_probe,
0140     .id_table = dmard09_id,
0141 };
0142
0143 module_i2c_driver(dmard09_driver);
0144
0145 MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
0146 MODULE_DESCRIPTION("DMARD09 3-axis accelerometer driver");
0147 MODULE_LICENSE("GPL");